Thomas Felis ¹, Kristine DeLong ², Amanda Godbold ^3
1 MARUM, University of Bremen (Bremen, Germany)
² Louisiana State University (Baton Rouge, LA, USA)
³ University of Southern California (Los Angeles, LA, USA)

This open session presents all contributions related to Theme 1, which are not covered by the below specialised sessions.

Daniel Harris¹, Jody Webster², Stephanie Duce³, Ana Vila-Concejo^2
1 The University of Queensland (Brisbane, Australia)
² The University of Sydney (Sydney, Australia)
³ James Cook University (Townsville, Australia)

In recent decades the decline in coral cover, recurrent global mass bleaching events and observations of sea level rise suggest that substantial long-term change in coral reef and coastal systems is already occurring. Predictions suggest that changes in climate and oceanographic conditions over the next 100 years will exceed the range observed during the last ≈80 years of scientific coral reef observations. This presents a substantial problem in both predicting and managing the future states of coral reef systems in a warmer world. Periods in the past may offer insights into the future trajectory of coral reef systems as they navigate a world of warming temperatures, rising sea levels, and changes in oceanographic conditions and water quality. Developing our understanding of geological reef development and the physical and environmental processes that have governed this development will provide crucial information regarding reef change over many spatio-temporal scales, from yearly to millennial, and from individual reefs to entire oceans. We seek submissions focused on understanding the environmental and physical processes that govern coral reef development, over multiple spatial and temporal scales, in order to provide some insights into the future of reef systems. Relevant fields of research include, coral reef geology and geomorphology, sea level research, climate change, tropical coastal processes and water quality, coral reef physical processes and numerical modelling.

Aaron O'Dea ¹, Erin Dillon², Loren McClenachan³, John Pandolfi ^4
1 Smithsonian Tropical Research Institute (Bocas del Toro, Panama)
² University of California Santa Barbara (Santa Barbara, CA, USA)
³ Colby College (Waterville, ME, USA)
⁴ University of Queensland (Brisbane, Australia)

To tackle the future of coral reefs it is essential to understand their ecological and environmental histories. Consequently, the use of historical data in coral reef ecology is expanding. Analytical approaches are maturing, compelling sources of data are being uncovered, and historians, paleontologists and archeologists are collaborating more fluidly with marine biologists and conservationists. This multidisciplinary session will explore how paleoecological, historical, and archeological data can reveal mechanisms of natural and human-driven change in coral reef communities to better understand how they function, both today and in the future. Submissions are welcomed on, but not limited to: incorporating spatial and temporal variation into baselines; resolving drivers of change in ecological structure; identifying legacy effects, non-analogue communities and refugia; developing emerging methods (e.g ancient DNA); and improving dialogue with reef managers, conservationists, and policymakers.

Andrea Dutton¹, Alessio Rovere ^2
1 University of Florida (Gainsville, Fl, USA)
² MARUM, University of Bremen (Bremen, Germany)

Fossil coral reefs are used by geoscientists to gather information on past sea level changes at many different time scales, from few hundred to several thousand years ago. Interdisciplinary collaborations between geoscientists and reef ecologists help to elucidate the paleo environments and the paleo water depths associated with fossil reef systems. This information is then coupled with radiometric dating of corals and geophysical models to understand the history of past sea level, land-based ice volume, and reef response. In this session, we welcome abstracts focusing on the different aspects related to the use of reefs as paleo sea level recorders, including dating and field techniques, particularly relevant sites, models of vertical land movements associated with reefs, rapid sea level changes recorded by reef environments, and reef response to past changes in sea level.

Henry C. Wu¹, Delphine Dissard², Jens Zinke³, Nathalie F. Goodkin^4,5
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² IRD-Sorbonne Universités (Paris, France)
³ University of Leicester (Leicester, United Kingdom)
⁴ Nanyang Technological University (Singapore)
⁵ American Museum of Natural History (New York, NY, USA)

Our understanding of current and future anthropogenic impacts (e.g. thermal stress and ocean acidification) on corals and coral reef ecosystems is severely limited due to the lack of reliable long-term monitoring and limited geographical coverage. Skeletal records from living and fossil, and tropical or subtropical biogenic carbonates such as surface and deep-sea corals, sclerosponges, bivalves, and foraminifera are key archives of environmental variability over historical time-scales. These records not only extend short instrumental records that started during the industrial era, but also allow for environmental reconstructions at unconstrained locations. Stable isotopes (e.g. δ¹¹B, δ¹³C, δ¹⁵N) and trace elements (e.g. B/Ca, Sr/Ca, Li/Mg, etc.) incorporated into skeletons of calcifying organisms provide an indirect tool to reconstruct variations in seawater and calcification pH, ¹³C Suess Effect, DIC and carbonate chemistry, thermal stress, sediment and riverine discharge or nutrient loading, light intensity, water mass dynamics, and coral performance in extreme environments. This session aims to present reconstructions that identify the most prevalent stressors on corals and coral reef ecosystems and assess the interaction of multiple stressors on their resilience through time. In particular, we welcome regional to global scale contributions that characterize and precisely quantify recent or historical trends of OA, coral responses to past bleaching events, biologically mediated calcification mechanisms and/or "vital effects", and their sensitivities to environmental changes. Contributors may include coral biologists and physiologists who have concerns about the fidelity and limits of proxies (e.g. calibration, analytical issues, application) or analyzing past bleaching or stress events using geochemical techniques. Ecological modelers working to increase our understanding of the impacts of OA on the calcification of corals and reef community are also encouraged.

Amanda Godbold ¹, Anna Weiss², David Bottjer^1
1 University of Southern California (Los Angeles, LA, USA)
² University of Texas at Austin (Austin, TX, USA)

Corals have been around for millions of years and have survived some of the deadliest events in Earth's history, including the "Big Five" mass extinctions. Their resiliency begs the question, how do these seemingly delicate organisms persist? This session aims to unite paleoecology and modern ecology for the purpose of understanding the extinction, survival, and recovery of corals throughout time. Each discipline offers unique insight into these important topics. The geologic record offers an abundance of time allowing natural experiments in climate and environmental change to be viewed in their entirety. Fossil reefs allow us to explore the evolutionary history of reefs in response to environmental changes as well as extinction selectivity of coral species. The modern has exceptional resolution allowing for detailed analyses. Modern reefs enhance our understanding of ecological phase shifts and the importance of connectivity in the survival of these ecosystems. Combining insights from the past with modern observations provides a powerful perspective that can be used to tackle complex concepts such as the range shifts of corals due to climate change and the development of refugia.

Kristine DeLong ¹, Diane Thompson², Thomas Felis³, Hali Kilbourne^4
1 Louisiana State University (Baton Rouge, LA, USA)
² University of Arizona (Tucson, AZ, USA)
³ MARUM, University of Bremen (Bremen, Germany)
⁴ University of Maryland (College Park, MD, USA)

The tropical oceans are uniquely positioned to serve as the pulse of climate change and climate variability since they contain warm pools that feed vast amounts of evaporation to the atmosphere driving the climate system. The lack of instrumental observations in the tropical oceans, both spatially and temporally, is a major hindrance to understanding climate variability and resolving climate model biases in the tropics. Long-lived massive corals contain records of past ocean conditions in their skeletons that can be used to understand climate variability in the recent past and in other warm periods, such as the Last Interglacial (125 ka) and Mid-Holocene (5-6 ka). One of the largest sources of climate variability is El Niño Southern Oscillation (ENSO) that occurs in the Tropical Pacific Ocean and impacts far flung regions. El Niño events during past 30 years have also driven higher reef temperatures leading to coral bleaching for large number of coral reefs. The Inter-American Seas (Gulf of Mexico and Caribbean Sea) is another prominent HotSpot for future climate change impacts including more intense tropical cyclones and droughts. Therefore, it is of foremost importance to expand our observational record, using corals as climate archives, to understand climate variability and extreme events so we can better predict future impacts of climate extremes on coral reefs. There is a strong need for a more comprehensive, end-to-end approach for climate assessments at a basin scale including better integration of paleoclimatic evidence, atmospheric and oceanic observations, physical understanding, model evaluation, and future projections. This session seeks contributions to increase our understanding of tropical climate variability in the past, present, and future using observations, coral and other marine paleoclimate proxies, and model simulations.

Götz B. Reinicke ¹, Gert Wörheide ², Iris Sampaio ^3
1 German Oceanographic Museum (Stralsund, Germany)
² LMU München (München, Germany)
³ Tel Aviv University (Tel Aviv, Israel)

This open session presents all contributions related to Theme 2, which are not covered by the below specialised sessions.

James Reimer ¹, Danwei Huang², Francesca Benzoni^3
1 University of the Ryukyus (Nishihara, Japan)
² National University of Singapore (Singapore)
³ University of Milano-Bicocca (Milan, Italy)

The myriad of life forms on the coral reef have traditionally been studied based on gross morphology, yet a wide variety of data ranging from small-scale morphology to DNA barcodes and genomic sequences have challenged the assumed order of many important reef groups. The sheer volume of data produced by these new approaches has enabled necessary revisionary work that is already impacting estimates of biodiversity at various spatial and temporal scales. In particular, geographic patterns are being updated, and extinct organisms can be studied alongside living ones, drawing a more accurate and holistic picture of coral reef biodiversity in an evolutionary perspective. This session focuses on findings from the integration of novel morphological, barcoding, genomic and transcriptomic techniques, as well as standardised sampling tools such as the Autonomous Reef Monitoring Structures, to uncover biodiversity, biogeographic and evolutionary patterns of coral reef organisms. The session will offer valuable perspectives on how modern taxonomy and evolutionary studies can contribute to the conservation of coral reefs.

Jacqueline Padilla-Gamino ¹, Yossi Loya², Saki Harii³, Elizabeth Lenz⁴, Tom Shlesinger ^2
1 University of Washington (Seattle, USA)
² Tel Aviv University (Tel Aviv, Israel)
³ Sesoko Station (Okinawa, Japan)
⁴ Hawaii Institute of Marine Biology (Kaneohe, HI, USA)

Reproduction represents the culmination of several physiological events within an individual's life, and is the first step in producing new recruits to marine ecosystems. With the aim of better understanding the factors that control the spawning synchrony and reproductive output of reef organisms, this session will bring together experts in different fields in order to share their findings on how environmental factors, and changes in the environment, can affect reproduction at the individual, population, and molecular levels. The session will highlight multidisciplinary research, including but not limited to the following topics: natural variability in reproductive cycles, parental effects, spawning synchronicity, chronobiology, phenology, gamete quality, fertilization success, larval dispersal, reproductive phenotypic plasticity, and the effects of environmental factors (light, ocean acidification, temperature, nutrients, pollutants, sedimentation) on the reproduction, settlement, and growth of new recruits. The session seeks to bring together scientists working in different coral ecosystems and from different regions of the world, to share novel insights and establish collaborations leading to an international coral-reef reproduction network that will integrate reproduction data from coral-reef organisms in different parts of the world. This will provide an immensely useful tool for the scientific community and coral-reef managers to track spawning events, generate long-term spawning time-series, and identify reproductive patterns over larger spatial and temporal scales. In turn, it will help us to better predict the effects of climate change on the reproductive success of corals, which is essential for the resilience and persistence of coral reefs and for the survival of many species in the tropical seas.

Kelly E. Speare ¹, Aaron C. Hartmann², Kristen L. Marhaver^3
1 University of California, Santa Barbara (Santa Barbara, CA, USA)
² Harvard University (Cambridge, MA, USA)
³ CARMABI Research Station (Curacao)

Anthropocene coral reefs have undergone massive changes in coral abundance and community composition, motivating ecologists to predict potential trajectories for recovery and factors that could thwart recovery. A growing body of work has identified important pathways by which corals, and the conditions they experience, influence future generations of corals and the assembly of ecosystems around them. For example, corals in denser populations produce disproportionally more larvae than corals in diffuse populations, and environmental conditions can influence the quantity and quality of coral offspring via maternal effects. Transgenerational effects can further influence coral offspring through adaptation (genetic) or acclimatization (epigenetic, microbial, or viral) to environmental change. In degraded systems, relatively weedy coral species are necessary to facilitate natural recruitment and outplant survival of more fragile species. While reefs were once thought to undergo a small number of predictable phase shifts, new datasets reveal complex path dependencies that affect community assemblage on a site-by-site basis. Finally, the re-establishment of coral populations in heavily degraded sites has produced so-called "novel ecosystems" made up of non-traditional, yet ecologically functional, species assemblages. What will coral reefs look like in the next 100 years? How will today's remnant, resilient, and recovering reefs influence these trajectories? This session will bring together ideas from across disciplines to ask the broad question: How are the corals of today influencing the coral reefs of the future? We invite contributions that address this question at all levels, from individual corals, to populations, communities, and ecosystems. This session aims to be highly interdisciplinary, bringing together work from empirical, theoretical, and applied approaches from any reef system.

Malin Pinsky ¹, Peter Buston ², Michael Berumen³, John Majoris³, Laura Gajdzik^3
1 Rutgers State University (New Brunswick, NJ, USA)
² Boston University (Boston, MA, USA)
³ KAUST (Thuwal, Saudi Arabia)

The dispersal of individuals among patchily distributed habitats connects marine populations across space, allowing recovery from disturbance, resilience in the face of chronic stressors, and even driving adaptive evolution in response to a changing environment. For this reason, understanding the causes and consequences of larval dispersal is a major goal of 21^st century marine ecology, mainly in an effort to describe the probability of larval exchange, or connectivity, among populations. Despite advances in our understanding of why dispersal varies among species, we still know stunningly little about the causes of variation in dispersal among individuals within species. Intraspecific variation sets the stage for evolution and has important consequences for population dynamics, species interactions, and conservation efforts. Understanding intraspecific variation will require a much stronger integration of oceanography, behavior, genetics, physiology, and ecology and evolution. To coordinate current research efforts and determine the state of the field, we invite submissions from scientists conducting  research on larval behavior, the genetic basis for larval dispersal traits, the physiology of dispersal, biophysical simulations of larval dispersal, the ecological consequences of dispersal kernels, the evolution of dispersal kernels, or other relevant topics. Experiments, observations, theory, simulations, field and lab studies are all welcome.

Christopher Cornwall ¹, Steeve Comeau², Guillermo Diaz-Pulido³, Maggy Nugues^4
1 Victoria University of Wellington (Wellington, New Zealand)
² Sorbonne Université (Villefranche-sur-mer, France)
³ Griffith University (Brisbane, Australia)
⁴ PSL Research University (Perpignan, France)

Coralline algae are important species on coral reefs that act as a settlement substrate, cement together and create reefs. Despite their ecological importance, we still have limited information on their ecological role, physiology, calcification and taxonomy/systematics. Additionally, understanding causes of the variability in their responses to global and local environmental changes in lacking. This session aims to bring together researchers that are working on coralline algae with a particular focus on the effects of environmental change, taxonomy, systematics and evolution, physiology and calcification, ecology, and contribution to reef accretion for these key taxa. With respects to environmental change, we welcome research that varies across scales, from mechanistic physiological and molecular effects through to larger-scale studies estimating the contribution of coralline algae to the accretion and functioning of future coral reefs. We are particularly interested in studies that go beyond the effects of a single stressor, that investigate the potential for coralline algae to acclimate and/or adapt to environmental changes, assessments of the role of phylogeny, or those that assess changes in their ecological role or function and the implications for coral reef ecology.

Andreas Haas¹, Christian Wild², Anna Woodhead ^3
1 NIOZ and Utrecht University (Texel, The Netherlands)
² University of Bremen (Bremen, Germany)
3 Lancaster University (Lancaster, UK)

This open session presents all contributions related to Theme 3, which are not covered by the below specialised sessions.

Yvonne Sawall ¹, Chiara Pisapia², Andreas Andersson^3
1 BIOS Bermuda Institute of Ocean Sciences (St. George's, Bermuda)
² California State University, Northridge (Northridge, CA, USA)
³ Scripps Institution of Oceanography (La Jolla, CA, USA)

As a result of global climate change and local anthropogenic disturbances, coral reef ecosystem functions such as net organic carbon production and net calcification are likely to change during the twenty-first century. However, to advance our understanding of the potential responses of coral reefs to environmental change, we first need to understand the natural dynamics of reef metabolism and related biogeochemical processes. While we have learned extensively about organism responses to a range of environmental parameters in lab-based experiments, we have limited understanding about organism responses in-situ where multiple environmental factors act simultaneously and on different temporal and spatial scales. Furthermore, our current understanding is even more limited in terms of how organism performance scale to community and ecosystem scales, including how species interactions and ecological feedbacks affect the net metabolism. This is important to consider because the net metabolism alters seawater chemistry, which, in turn, may affect the performance of neighboring or downstream habitats and communities. In this session, we are particularly interested in contributions that assess the dynamics of organism, community and/or ecosystem metabolism and biogeochemical processes considering (i) multiple environmental factors, (ii) species interactions, (iii) lab-based versus in-situ approaches, (iv) different spatial and temporal scales (e.g., using up-scaling approaches) and/or (v) predictive models of reef metabolic function. We also welcome introductions of new methodologies advancing our understanding on reef metabolism dynamics at present and in a future warmer and more acidic ocean.

Anna Woodhead ¹, Ruth Thurstan², Tomas Chaigneau², Susan Yee ^3
1 Lancaster University (Lancaster, UK)
² University of Exeter (Exeter, UK)
³ US Environment Protection Agency, Gulf Ecology Division

Coral reef ecosystems underpin important benefits to people, known as ecosystem services. These contribute to human wellbeing but with current and future changes to reef social-ecological systems, how have and how will ecosystem services on coral reefs change? Ecosystem services occur via interactions between social and ecological systems, hence changes in ecosystem services could arise from ecological change, social change or multiple combinations therein. These might lead to emerging services, for instance the tropicalisation of temperate areas could underpin new fisheries. Changes in the use and importance of services could also occur. For example, changes in the socio-economic circumstances of individuals can modify the processes and motivations behind service use. Biophysical, social, economic and cultural changes all affect past and future coral reef ecosystem services, thus accurately capturing and predicting these interactions will require a broad disciplinary approach. We invite abstracts from different disciplines, looking at different ecosystem service types that address one or more of the following: -Evidence of changes in coral reef ecosystem services following social and/or ecological change in tropical coastal areas. -Novel approaches to capturing ecosystem service change. This could include looking to the future (e.g. scenarios) or to the past (e.g. syntheses of historical data). -Conceptual development and future directions. This could consider the types of evidence, knowledge and values that will be needed, as well as governance and management structures of coral reef social-ecological systems. Submissions should make explicit the approach they are taking towards capturing ecosystem services (e.g. historical ecology, ecological economics, contributions to wellbeing etc.). The session discussion will summarise how each talk addressed change in coral reef social-ecological systems with view to synthesising this work in an opinion piece.

Michael Fox ¹, Kristen Davis², Jörg Wiedenmann³, Gareth Williams^4
1 Woods Hole Oceanographic Institution (Woods Hole, MA, USA)
² University of California (Irvine, CA, USA)
³ University of Southampton (Southampton, UK)
⁴ Bangor University (Bangor, UK)

Shallow water coral reefs are traditionally considered nutritionally self-sustaining systems, capable of thriving in oligotrophic waters. But coral reefs exist across a wide range of oceanic nutrient concentrations, primary production, and anthropogenic impacts. Emerging evidence reveals that many reefs receive substantial inputs of exogenous nutrients from natural processes such as upwelling, internal waves, or lagoon flushing. These inputs can significantly increase background nutrient concentrations and enhance nearshore phytoplankton biomass. Under such conditions, many reefs exhibit higher coral cover, fish biomass, and overall ecosystem productivity. In contrast, nutrients associated with anthropogenic activities enter reef systems through agricultural runoff, sewage, or groundwater discharge where they often compromise ecosystem functioning. To date, much of the focus has been on the negative effects of nutrients on reef communities, while the synergistic roles of natural nutrient enrichment have received less attention. Resolving why nutrients can have contrasting impacts on different organisms and reef systems is an important next step in predicting the fate of coral reefs under future changes in coastal eutrophication and primary production. Recent advances in analytical techniques (e.g., compound-specific stable isotope analysis), high-resolution climate and biogeochemical modeling, and observational technologies (e.g., in situ and remote sensing) are creating opportunities to address the critical gaps in knowledge needed to develop innovative management strategies and refine predictions of coral reef trajectories. This session invites contributions from experimental, observational, and modeling studies that seek to quantify and understand the connections between nutrient supply, primary production, coral reef community structure and function, energy flow, and ecosystem resilience.
  

Ines D. Lange¹, Tyler Cyronak², Lauren T. Toth³, Coulson Lantz⁴, Lorenzo Alvarez-Filip ^5
1 University of Exeter (Exeter, UK)
² Nova Southeastern University (Dania Beach, FL, USA)
³ U.S. Geological Survey (St. Petersburg, FL, USA)
⁴ Southern Cross University (Lismore, Australia)
⁵ Universidad Nacional Autónoma de México (Puerto Morelos, Mexico)

The production and maintenance of complex calcium carbonate structure is perhaps the most critical function of a healthy coral reef ecosystem, providing habitat for numerous marine species and acting as a breakwater that dissipates wave energy and protects shorelines. The build-up of reef framework is driven by counteracting rates of calcium carbonate production (i.e., calcification) and calcium carbonate breakdown and loss (i.e., dissolution, bioerosion, off-reef transport). Recent work has shown that the accelerating pace of global anthropogenic change, including increases in seawater temperature, ocean acidification, and sea level rise will significantly impact the capacity of reefs to sustain positive calcium carbonate budgets and associated ecosystem services. Although the footprint of anthropogenic disturbance will be different across marine regions and habitats, the repercussions for many reef ecosystems may be broadly similar: i) progressively shifting towards net negative calcium carbonate budget states; ii) becoming structurally flatter; and iii) having lower vertical growth rates. To understand how this progression will impact reef geo-ecological functions it is critical to understand both impacts on the biological processes that drive carbonate production on the reef surface and the breakdown processes that affect the accumulation of the underlying reef structure. For this session we invite contributions that explore calcium carbonate budgets and coral reef geo-ecological functions in the Anthropocene and address questions pertaining to: i) how changes in the abundance of key calcifying groups impact habitat complexity and reef budgets, ii) how the changing intensity of destructive processes impact reef budgets, iii) how rates of net reef accretion are changing now and predictions for the future, and iv) the implications of these changes for the maintenance of geo-ecological ecosystem services provided by coral reefs. We also welcome contributions that discuss novel approaches to quantifying calcium carbonate budgets, reef accretion, carbonate break-down and reef geo-ecological functions.

Christian R. Voolstra¹, Peter J. Schupp², Rebecca Vega Thurber³, Tilmann Harder ^4
1 University of Konstanz (Konstanz, Germany)
² University of Oldenburg (Oldenburg, Germany)
³ Oregon State University (Corvallis, OR, USA)
⁴ University of Bremen (Bremen, Germany)

This open session presents all contributions related to Theme 4, which are not covered by the below specialised sessions.

Ernesto Weil ¹, Caroline Rogers², Aldo Croquer³, Laurie Raymundo⁴, Joleah Lamb⁵, Greta Aeby ⁶, Beatriz Casareto^7
1 University of Puerto Rico (Mayaguez, Puerto Rico)
² US Geological Survey (St. John, US Virgin Islands)
³ Dept. Estudios Ambientales (Caracas, Venezuela)
⁴ University of Guam (Mangilao, Guam)
⁵ University of California (Irvine, CA, USA)
⁶ Qatar University (Qatar)
⁷ Shizuoka University (Shizuoka, Japan)

Marine ecosystems, from the temperate zones to the tropics and from the shore down to mesophotic depths (40-150m), are being exposed to increasing seawater temperatures and overall water quality deterioration. Mounting evidence has confirmed severe global degradation of tropical and temperate coral, octocoral, sea-grass and rocky-shore ecosystems. Mass mortality events documented over the last four decades, impacting foundation and/or keystone species in these important communities are mostly linked to large thermal anomalies associated with Global Climate Change (GCC). Heat accumulation then triggers bleaching and outbreaks of new and old diseases, and their synergistic effects, producing the mortalities. Overall, the ecological integrity of the affected communities degrades, affecting structure, function, diversity, and the ecological services they provide. The study of coral reef disease began as a novel science 48 years ago, and significant advances have been made in many areas (pathology, etiology, epizootiology and immunology). Nevertheless, there are still open discussions on terminology, best epizootiological approaches, lagging pathological molecular and studies, geographic distributions, diagnostic signs, short vs. long temporal observations, amongst other topics. This session is intended as a venue to summarize the last four-to-five decades of research on marine diseases, with emphasis on coral reefs and other key coastal communities. We encourage presentations that summarize major findings and advances in studies of marine diseases, including topics such as holobiont dynamics and disease, pathogen variability and dynamics, role of bacteria, fungi, viruses and other parasites, local and exotic pathogens, etc. We also encourage submissions that advance the study and documentation of the ecological, economic and sociological impacts of disease, such as mass mortalities, geographic patterns, spatial and temporal variability of persistent diseases vs. seasonal outbreaks, environmental and human-induced drivers, and continuing challenges to research. We hope to produce a review manuscript as a product of this session, summarizing the major topics and progress, what we have learned, the major challenges and limitations and how these can be addressed.

Amy Apprill ¹, Koty Sharp², Tracy Ainsworth³, Linda Wegley Kelly ^4
1 Woods Hole Oceanographic Institution (Woods Hole, MA, USA)
² Roger Williams University (Rhode Island, USA)
³ The University of New South Wales (Sydney, Australia)
⁴ San Diego State University (San Diego, CA, USA)

Microorganisms are associated with diverse protist and animal life on reefs and these microbial communities or microbiomes play important roles in the health, ecology and even behavior of their hosts. Recent advances in sequencing, microscopy and other technological approaches have provided opportunities to examine host-associated microbiomes in-depth, providing glimpses into patterns of microbial diversity, community composition as well as the location and specific symbiotic nature of microorganisms associated with reefs and reef-dwelling hosts. With this new wealth of knowledge brings an opportunity to understand the defining patterns governing these relationships among diverse hosts, environments and experimental conditions, which may provide novel insights into host-microbiome interactions. At the same time there is also an opportunity to learn from disparate host-microbiome patterns, which may be central to understanding specific organismal or environmental adaptations. The goal of this session is to bring together microbiome studies across diverse hosts (protists, corals, fish, invertebrates, etc.), representing disparate reef environments (tropical, temperate, cold and deep water) as well as within the context of natural or induced experimental conditions (e.g., temperature stress, ocean acidification, disease, macroalgal exposure, etc.). As a scientific community and throughout the session, we will compare, contrast and discuss what is similar and distinct in microbiome diversity, community structure and defining taxa within these studies, with the overarching goal of shedding new light on governing principles of host-microbiome relationships and advancing our understanding of how those host-microbiome relationships respond to environmental change on reefs.

This session was joined with the original session "How do microbes manipulate reef biochemicals and alter ecosystem processes?"
This session welcomes work across scales and approaches that seeks to understand how microorganisms interact with coral reef biogeochemistry. Processes such as primary production, calcification, respiration, dissolution, nutrient remineralization and organic matter recycling all have well-established links to to reef microbes; however advances in technology offer new ways to investigate the linkages between specific microbial populations and their surrounding environment. The complexity of microbial communities in reefs, including planktonic, benthic and host associated habitats, demands deeper exploration of the interplay between microbes and biogeochemical fluxes which underpins coral reef biology. Microbes are also intimately involved in worldwide changes on coral reefs, including bleaching, diseases and phase shifts of dominant benthic macro-organisms. Furthermore, effective coral reef management in the face of local and climatic stressors requires a clear understanding of the role of microbial communities in regulating ecosystem functions such as coral growth rates, nutrient availability, and overall metabolic budgets. Topics that would be relevant in this session include interactions between microbes and coral reef organic matter, microbial transformations of nutrients, microbiome influences on host physiology relevant at the ecosystem scale, contributions of microbial biomass to reef food webs, or 'omics-informed ecological investigations of specific microbial populations/communities involved in biogeochemical cycling.

William Fitt ¹, Aki Ohdera², Monica Medina^3
1 University of Georgia (Athens, GA, USA)
² Carnegie Institute (Baltimore, MD, USA)
³ Pennsylvania State University (State College, PA, USA)

The upside-down jellyfish (Cassiopea xamachana) is an emerging model system to study cnidarian-algal-microbial symbiosis. A growing Cassiopea scientific community is not only addressing symbiosis-related questions using a broad range of approaches from molecular to the organismal level, but are utilizing the system for behavioral, ecological, and environmental inquiries. The life cycle of the jellyfish is now well established in multiple laboratories around the world, the genome has been sequenced and genetic tools are in development. Knowledge of the biology of microbial partners (e.g. settlement-inducing bacteria, strobilation-inducing Symbiodinacea) that interact with this animal host is also increasing, again with genomic and genetic manipulation also in the horizon. The enhanced experimental potential, broad application outside of cnidarian biology, and relative low cost implementation of this system, deserve a venue at the ISRS meeting such that laboratories, especially in developing nations, can learn and take advantage of the research possibilities Cassiopea provides to study topics such as environmental monitoring, ecoloigcal interactions, evolutionary development, evolution of behavior, and as a proxy to study onset and breakdown (e.g. bleaching) of coral-algal symbiosis.

Brian Walker ¹, Karen Neely¹, Erinn Muller², Josh Voss³, Greta Aeby^4
1 Nova Southeastern University (Fort Lauderdale, Fl, USA)
² Mote Marine Laboratory (Sarasota, FL, USA)
³ Florida Atlantic University (Boca Raton, FL, USA)
⁵ Qatar University (Qatar)

Outbreaks of coral diseases are expected to become more frequent and severe from a combination of chronic local stress (overfishing, land-based pollution) and global climate change. The first step in mitigating damage from disease outbreaks is an understanding of the underlying disease processes. Concomitantly, there is an urgent need to develop field intervention techniques, disease response plans, and engage citizen scientists in these efforts. Efforts to understand, control, or mitigate these outbreaks may be challenging, but can be considered at the lesion, colony, reef, or landscape level. Efforts should be collaborative involving researchers, managers, and community members. This session aims to convene international reef scientists and managers who have, or anticipate having to respond to disease outbreaks, and invites them to present the latest coral disease research, intervention approaches and, response plan success and failures. Regions throughout the world are facing the problems with disease outbreaks and sharing "lessons learned" can help researchers and managers address this growing problem.

Benjamin Mueller¹, Marta Ribes², Cynthia Silveira³, Jasper de Goeij^1
1 University of Amsterdam (Amsterdam, The Netherlands)
² Institut de Ciències del Mar (Barcelona, Spain)
³ San Diego State University (San Diego, CA, USA)

Since the first description of coral reefs it remains an enigma how such diverse and productive ecosystems can flourish in nutrient-poor waters, the equivalent to a marine dessert. It is becoming increasingly evident that certain element recycling pathways mediated by benthic holobionts (host plus associated microbiota) and free-living microbes play key roles in ecosystem functioning. For example, the transformation of dissolved organic matter (DOM; the largest, yet largely unavailable food source) to particles via the respective microbial and sponge loop reduce the loss of elements stored in this DOM to the open ocean and is considered pivotal to sustain reefs under oligotrophic conditions. However, global and local stressors cause shifts in benthic communities and affect levels and composition of organic and inorganic nutrients, as well as the stoichiometry of elements in reef waters. Efficient element recycling pathways that initially allowed reefs to evolve under nutrient-poor conditions, are now hypothesized to reinforce ongoing benthic shifts and the deterioration of these systems. Recent examples are the accumulation of microbial biomass at the expense of element transfer to higher trophic levels ("microbialization") and the release of organic and inorganic nutrients by sponges ("vicious circle"). Both theories suggest to stimulate an increase in opportunistic microbes causing low oxygen levels and detrimental effects on coral health, and to further fuel algal growth. This session invites abstracts on the latest findings on organic and inorganic element cycling by benthic holobionts and free-living microbes and their role in ecosystem function. The aim is to bring together studies from organism to ecosystem levels assessing the current status, making future projections, and discussing possible management interventions. Contributions from mangrove, seagrass, and deep-sea environments are encouraged to foster a broad interdisciplinary exchange.

Claudia Pogoreutz¹, Anny Cárdenas¹, Raquel Peixoto², Till Röthig^3
1 KAUST (Thuwal, Saudi Arabia)
² Federal University of Rio de Janeiro (Rio de Janeiro, Brazil)
³ University of Derby (Derby, UK)

Although reef-building corals and other reef organisms are increasingly recognized as holobionts, we have limited understanding of how associated microorganisms interact with their eukaryotic hosts, with each other, and with their environment. Mounting evidence suggests that host-associated microorganisms other than Symbiodiniaeae may be central to both resilience and degradation of coral reefs. Hence, to obtain a better understanding of key coral reef holobionts, it will be paramount to integrate functional approaches to reef microbiology. Specifically, several issues are of interest: 1) the identification and quantification of microbial metabolic traits in key reef holobionts, 2) mechanistic approaches to resolve microbial metabolic contribution to holobiont functioning, and 3) operationalizing microbiome manipulations, i.e. employ microorganisms and/or microbial consortia to enhance benefitial holobiont traits (‘marine probiotics’). Addressing these issues will be critical for an integrated understanding of the reef ecosystem, and may offer new venues for innovative management approaches. We invite oral and poster contributions using interdisciplinary approaches aiming at either functionality that explains the mechanistic underpinnings of holobiont-microbiome associations or their modification to boost holobiont resilience. Such approaches may include established ecophysiological techniques, combining next-generation “omics” and high-resolution imaging techniques, or microbiome manipulations and marine probiotics and their potential application in conservation and restoration. The goal of this session is to communicate most recent advances, challenges, and perspectives in exploring symbioses on coral reefs, and to provide a forum for collaboration and exchange.

Claudio Richter¹, Covadonga Orejas ^2
1 AWI Bremerhaven (Bremerhaven, Germany)
² Instituto Español de Oceanografía (Palma de Mallorca, Spain)

This open session presents all contributions related to Theme 5, which are not covered by the below specialised sessions.

Erik Caroselli ¹, Nuria Teixido², Jaap Kaandorp³, Zvy Dubinsky⁴, Stefano Goffredo^1
1 University of Bologna (Bologna, Italy)
² Sorbonne Université, CNRS (Villefranche-sur-Mer, France)
³ University of Amsterdam (Amsterdam, The Netherlands)
⁴ Bar Ilan University (Ramat-Gan, Israel)

While most studies about the impact of climate change on marine ecosystems focus on tropical regions, knowledge about the impacts on temperate reefs is relatively scarce. Nevertheless, temperate areas host biodiversity hotspots (e.g. the Mediterranean Sea) and are projected to be severely impacted by climate change. During the last two decades, research on the impact of climate change on temperate biota has been performed with experiment in controlled conditions, mesocosms, and "natural laboratories", such as those found at some volcanic carbon dioxide vents or along natural temperature gradients. Some of these peculiar natural settings have been discovered in temperate regions and represent a unique opportunity for climate change-related studies. This session focuses on the impacts of various aspects of climate change (e.g. seawater warming, acidification, and deoxygenation, sea level rise, increased frequency of extreme events) on temperate species, ecosystems, and regions and how they relate to the expected impacts in tropical regions.

Ronald Osinga¹, Gert Wörheide², Cecilia D’Angelo^3
1 Wageningen University (Wageningen, The Netherlands)
² LMU München (München, Germany)
³ University of Southampton (Southampton, UK)

This open session presents all contributions related to Theme 6, which are not covered by the below specialised sessions.

Emma Camp¹, Jessica Bellworthy ², Nadia Santodomingo³, Eslam O. Osman⁴, Guilhem Banc-Prandi ², Verena Schoepf ^5
1 University of Technology Sydney (Sydney, Australia)
² Interuniversity Institute for Marine Science (Eilat, Israel) 
³ Natural History Museum (London, UK)
⁴ Pennsylvania State University (Pennsylvania, PA, USA)
⁵ The University of Western Australia (Perth, Australia)

Rapid environmental change is compromising coral reefs globally, requiring enhanced knowledge on which habitats will be more likely to serve as coral refugia. Insights gained by studying geographic locations of stress tolerant corals (e.g. the northern Red Sea) and those in marginal and extreme coral habitats that house corals living under suboptimal environmental conditions (e.g. mesophotic reefs, latitudinal extremes, inter-tidal-habitats, turbid reefs, and reef-neighbouring habitats –including up-welling, mangrove habitats, seagrass and CO₂ vent sites), can be used to better manage such sites and aid coral reef resilience. Research into these locations are revealing novel habitat functions, including refuge capacity, preconditioning to climate change, and stocks of genetic biodiversity. Furthermore, studies on the traits and physiological mechanisms of individuals from these habitats are showing the adaptive and/or acclimatory processes required to survive stress.  Thus, these systems are providing unique natural laboratories to enhance our understanding of coral survival under suboptimal conditions, while accounting for timescales of long-term acclimatisation, adaptation and local community reorganisation to the prevailing conditions. In this session, we seek to attract a diverse range of abstracts that contribute new knowledge on refugia, extreme and marginal coral habitats and their reef associated taxa to: i) further our understanding of how environmental conditions contribute to novel ecosystem services for resident populations, and to ii) enhance our understanding of the acclimation/adaptation mechanisms that facilitate survival. Collectively the session will seek to advance our knowledge of the location, vulnerabilities and value of reef refugia, while advancing our knowledge of the mechanisms that facilitate survival of resident populations.

Marc Slattery¹, Frederic Sinniger², Gal Eyal³, Tyler Smith⁴, Kimberly Puglise⁵, Alejandra Hernandez^6
1 University of Mississippi (Oxford, MS, USA)
² University of Ryukyus (Sesoko, Japan)
³ The University of Queensland (Brisbane, Australia)
⁴ University of the Virgin Islands (St. Thomas, U.S. Virgin Islands)
⁵ NOAA National Ocean Service (Silver Spring, MD, USA)
⁶ California Academy of Sciences (San Francisco, CA, USA)

Research on mesophotic coral ecosystems (MCEs: ~30-150 m depth) has increased exponentially over the past decade. Increasing interest has been driven in large part by the “Deep Reef Refugia” hypothesis that suggests MCEs are less susceptible to the disturbances faced by nearby shallow coral reefs (e.g., coral bleaching, diseases, overfishing, and land-based pollution), and, through larval connectivity, could serve as potential “Lifeboats” for shallow reefs. As we address the challenging future of coral reefs, MCEs will clearly be an important topic, and assessing their role in the larger context of coral reefs requires addressing their basic ecological, physiological, and oceanographic processes. From this we can contextualize the origin and evolution of MCE flora and fauna relative to shallow reefs. This session will highlight recent research on MCEs from multiple perspectives such as: Biodiversity, Community structure and dynamics, Population connectivity, Biology of MCE organisms, and Geological and physical processes. Through this interdisciplinary approach, the session will explore both the similarities and differences of MCEs in comparison to shallow reefs, as well as conservation and remediation of MCEs in order to understand their roles as “Lifeboats”. Our goal is to increase the dialog with coral scientists focused on shallow reefs to improve our understanding of the complete coral ecosystem, and to tackle these, and other research priorities, in the context of the challenging future of coral reefs.

Stuart Sandin ¹, Mark Vermeij², Jennifer Smith¹, Gareth Williams^3
1 Scripps Institution of Oceanography (La Jolla, CA, USA)
² CARMABI / University of Amsterdam (Curacao / The Netherlands)
³ Bangor University (Bangor, UK)

Recent efforts have sought to describe in detail the decline of reef structure, using the diversity and species composition of little-impacted reefs as a reference for 'pristine' or 'baseline'. One approach to management is to strive toward returning impacted reefs back toward these baselines. In many locations, however, there is little chance of 're-wilding' reefs to historic conditions due to the ongoing needs and impacts of human populations (i.e., fishing, shoreline use, climate shifts). A complementary form of management is to target improved functioning of reef communities to provide improvements and sustainability in the services provided to local populations. A growing number of case studies are emerging of well-functioning coral reefs being found in unexpected locations. Extreme examples include thriving coral growth in outflow plumes from power plants, clear and microbe-light waters adjacent to poorly maintained sewage systems, and extremely productive reef fisheries on heavily populated islands. Observational data from across the variety of coral reef contexts assists us in learning about the variation and potential of reef communities to adapt to changing environmental conditions. This session calls to the coral reef community to share case studies of reefs showing strength in unexpected locations. The goal will be to find generalities in the case studies to guide practical management looking forward.

Arjun Chennu ¹, Manuel Gonzalez Rivero ^2
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² Australian Institute of Marine Science (Townsville, Australia)

This open session presents all contributions related to Theme 7, which are not covered by the below specialised sessions.

Josh Levy¹, Carlie Wiener², Phil McGillivary ³, Ved Chirayath^4
1 University of Hawaii (Honolulu, HI, USA),
² Schmidt Ocean Institute (Palo Alto, CA, USA)
³ US Coast Guard Pacific Area Science Liaison (Alameda, CA, USA)
⁴ NASA Ames Research Lab (Moffett Field, CA, USA)

Traditionally, coral research and ecosystem monitoring activities involve the use of conventional diver surveys for shallow reef systems, and research ships with submersible vehicles for mesophotic and deep reefs.  High costs of diver and ship operations, and their inability to support long-term persistent observations due to endurance constraints, weather limitations, and diver safety, emphasize the need for more cost-efficient and scalable alternatives. To address the monetary and time challenges of reef research and monitoring, we need to reduce the cost of obtaining data at biologically relevant spatial and temporal scales. Proposed solutions include using unmanned systems, data fusion, analytics, and visualization techniques to collect and process data for use by both science and conservation communities. Unmanned technologies have the ability to collect data over large areas at a low personnel and monetary cost, and disseminate data in near real time, making them increasingly useful assets for reef management. This session will focus on emerging technologies to support coral research and ecosystem monitoring with improved operational scale, coverage, resolution, and cost-efficiency. The session will assess robotic and software innovations, data fusion/processing, visualization techniques, intelligent data use for reef studies, and how to accelerate their adoption by ocean scientists and ecosystem managers. Session topics may include effective applications of innovative robotic survey, monitoring, mapping, and interactive research platforms, such as autonomous aerial, surface, and underwater vehicles, and other remote sensing methodologies. Also of interest are adaptive survey techniques involving analytical decision support, cross-platform coordination and communication, and how intelligent data use can increase operational efficiency of robotic marine surveys.

Philippe Laissue ¹, Nils Rädecker ^2
1 University of Essex (Colchester, UK)
² École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

Our better understanding of the cellular processes underlying the biology of reef organisms and the dynamics within their communities depends on the ability to image their morphology and composition over time and at high spatial resolution. Imaging calcifying organisms such as corals however, is complicated by their opaque aragonite skeleton, the complex microtopography of the surface and the difference in scale that exists between the many symbiotic partners that form the holobiont. Traditional analytical techniques have relied on the physical separation of the main components– calcified skeleton, coral tissue and symbionts. Such approaches 1) preclude observation of dynamic host-symbiont or host-pathogen interactions, and 2) lose all information about the spatial distribution of compounds within tissues and cells. The first limitation can be overcome by non-invasive, live imaging techniques such as light-sheet fluorescence microscopy, optical coherence tomography, and/or digital holographic microscopy. Importantly, live imaging can be combined with other powerful in situ techniques such as microfluidics and micro-electrodes, which enables the observation and measurement of in vivo morphological, behavioural and physiological responses of an organism to environmental stress (e.g. enhanced mucus production prior to bleaching, zooxanthellar expulsion in response to stress, and mesenterial filament dynamics in wound repair and pathogenicity). The second constraint can be overcome using high spatial resolution molecular imaging techniques such as nano-scale secondary-ion mass spectrometry (NanoSIMS) and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), which, when combined with stable isotopes, enables the quantification and/or identification of the flux of metabolites in an intact symbiosis. Live- and molecular imaging techniques are in fact, highly complementary, and the combination of the two has the potential to help answer some of the most fundamental questions remaining in coral reef research: how does the coral immune system function? What is the tipping point for the transition between health and disease? And, how will the coral holobiont respond to multiple stressors in the face of climate change? The techniques presented here are not limited only to coral. They can also be used to probe the composition of- and dynamics between different species within coral reef communities, from crustose coralline algae and cyanobacteria to microbiomes and the coral holobiont. In this session, we invite leading scientists to showcase their latest results and present the advantages of new imaging approaches. We encourage speakers to emphasise practical aspects, with the intention to stimulate usage of the showcased technique for addressing new biological questions.

Emma Kennedy ¹, Chris Roelfsema¹, Sarah Hamylton², Stuart Phinn¹, Greg Asner ^3
1 University of Queensland (Brisbane, Australia)
² University of Wollongong (New South Wales, Australia)
³ Arizona State University (Tempe AZ and Hilo HI, USA)

Advances in technologies to measure, map, model and monitor reefs from polyp to global scales, and integrate across a wide range of different data sets and disciplines have facilitated expansive work to scale-up reef research. More rapid data acquisition, better mechanisms for data sharing, and a growing community of reef scientists has allowed better and broader collaborations, from pooling global bleaching observations to citizen science monitoring. Many of the current challenges faced by reefs - including overfishing and climate change - are global in their nature. Some of our datasets, collaborations and tools are becoming more global too. What lessons have we learned from expanding our reach beyond the confines of disciplinary and geographical boundaries? This session aims to be highly interdisciplinary and welcomes submissions from any studies that seek to upscale their observations and findings, from macroecology, biogeography, earth systems monitoring, oceanography, conservation planning, social science and mapping global change and beyond!

Phillip A. Cleves ¹, Katie Barott^2
1 Stanford University (San Francisco, CA, USA)
² University of Pennsylvania (Philadelphia, PA, USA)

A major goal of coral biology is to better understand the genetic and cell-biological bases of how cnidarian-dinoflagellate symbioses are established and maintained, and how they break down under stress. Such an understanding would provide a solid foundation for attempts to mitigate the effects of stress and promote coral-reef conservation. In recent years, modern sequencing technologies have led to an abundance of transcriptomic and genomic studies of corals, which have resulted in many intriguing hypotheses about the mechanisms of interest. However, these hypotheses need rigorous testing before they can contribute reliably to conservation efforts. This session will focus on the latest advances in our understanding of cnidarian cell biology, including the major technological developments that are contributing to our ability to experimentally test these hypotheses. First, the development of model systems, such as the small sea anemone Aiptasia, the upside-down jellyfish Cassiopea, and coral cell culture, has allowed studies that would be difficult or impossible in corals themselves. Second, the application of advanced microscopy methods to the cell biology of cnidarian symbioses has facilitated examination of in vivo dynamics and micro-scale interactions. Third, and particularly revolutionary in its potential, is the application of new genetic methods, such as those based on CRISPR/Cas9, which enable generation of mutants that allow for rigorous examination of gene and protein function. The session will attempt to summarize both the state of the art in regard to the relevant technologies and the progress in biological understanding that has been made to date by applying these technologies.

Robert Richmond ¹, Kaho Tisthammer², Narrissa Spies^3
1 University of Hawaii at Manoa (Honolulu, HI, USA)
² San Francisco State University (San Francisco, CA, USA)
³ Pacific Islands Fish and Wildlife Office (Honolulu, HI, USA)

In a world of continuing and accelerating coral reef losses, it is essential to determine the key stressors, their thresholds, and combined effects in order to design, implement and evaluate the effectiveness of appropriate interventions.  Ecological approaches largely rely on correlation to determine relationships among multiple stressors and the effects on coral reef ecosystems, and it takes months, years and decades to measure many responses and trends. Molecular tools, including proteomics, genomics, metabolomics and transcriptomics, can identify true cause-and-effect relationships between stressors and responses over shorter time periods, from hours, to days and weeks. They can also be used to identify and quantify changes tied to stressor exposure in organisms on the reef and under controlled laboratory conditions. As molecular tools are further refined and associated costs decrease, it is now possible and practical to include these in coral reef assessment and monitoring programs. It is also possible to determine threshold stressor levels that result in impairment of functions such as reproduction, or result in outright mortality. This session is organized to include researchers studying organisms across coral reef taxa, resource managers who could use these data to guide interventions, stakeholders affected by coral reef losses, and policy makers who can apply such information to develop effective legislation to improve the effective allocation of limited human, institutional and financial resources to address and reverse the present downward trajectory of coral reefs. The intention of this session is to highlight the latest research, address how such studies can be applied to supporting coral reef persistence, resilience and restoration, and address key information gaps and management challenges.

David Miller ¹, Ira Cooke¹, Chris Voolstra², Iliana Baums ^3
1 James Cook University (Townsville, Australia)
² University of Konstanz (Konstanz, Germany)
³ Pennsylvania State University (Pennsylvania, PA, USA)

The ever-decreasing cost of high throughput sequencing technologies and their wide application outside of the traditional model organisms has enabled rapid progress in, and new perspectives on, many aspects of the biology of reef organisms, from corals to fish. This session will highlight novel findings from genomic, transcriptomic and metagenomic analyses of reef organisms, and the symbiotic interactions between various components of reef holobionts.

David Souter ¹, David Obura², Serge Planes³, Supin Wongbusarakum^4
1 Australian Institute of Marine Science (Townsville, Australia)
² CORDIO East Africa (Mombasa, Kenya)
³ CRIOBE (Moorea, French Polynesia)
⁴ NOAA Pacific Island Fisheries Science Center (Honolulu, HI, USA)

Despite the unquestionable value of coral reefs to local communities, national economies and global biodiversity, there has been a steady worldwide decline in their condition as a result of increasing local to global pressures. Prevention of further degradation and maintenance of resilience within these critical ecosystems is dependent on understanding the interdependence of reefs and people, and the implementation of appropriate and timely management actions. The foundation for such knowledge is gained through the implementation of targeted long-term and integrated monitoring programs. The Global Coral Reef Monitoring Network (GCRMN) is an operational network of the International Coral Reef Initiative (ICRI), and a worldwide network of coral reef scientists, managers, and organisations. Since its establishment in 1995, the GCRMN has produced five Status of Coral Reefs of the World reports between 1998 and 2008. These reports have had significant impact within the global scientific, NGO, government and United Nations (UN) communities, with the UN recognising GCRMN's significant role in monitoring progress toward coral reef-related Aichi Biodiversity Targets (Target 10) and Sustainable Development Goals (13 & 14). In response to calls by ICRI members, a new GCRMN Implementation and Governance Plan has been adopted, with an initial focus on the next Status of Coral Reefs of the World report. The report will be launched at ICRS 2020, and this mini-symposium will inform conference participants and a global audience of the current status of the world's coral reefs, the major threats they face, their socio-economic importance, and the initiatives being implemented to manage and conserve these critical ecosystems. This session welcomes contributions presenting long-term surveys of coral reefs, integrated datasets and innovative monitoring tools to promote greater collaboration and magnification of monitoring consistent with the UN Decade of Ocean Science for Sustainability.

Alexander Venn ¹, Sylvie Tambutté¹, Anton Eisenhauer², Virginie Chamard³, Ed Hathorne⁴, Fiorella Prada⁵, Stefano Goffredo⁵, Tali Mass ⁶, Jeana Drake^7
1 Centre Scientifique de Monaco (Monaco)
² GEOMAR (Kiel, Germany)
³ Institut Fresnel (Marseille, France)
⁴ GEOMAR (Kiel, Germany)
⁵ University of Bologna (Bologna, Italy)
⁶ University of Haifa (Haifa, Israel)
⁷ University of California Los Angeles (Los Angeles, CA, USA)

The two original sessions below have joined here:

How can innovative techniques to investigate calcification and its mechanism shed light into the past, present and future of coral reef organisms?
Calcification is the process by which tiny coral polyps build the largest bioconstructions on the planet, the coral reefs. Despite the biological and geochemical importance of calcification and more than 100 years of investigation, our understanding of this process and its underlying mechanism still remains patchy. Calcification is sensitive to many aspects of global environmental change, and improving understanding of calcification is the key to a clearer vision of how coral reefs responded to past environmental change and how they will fare in future decades. Contemporary research on calcification is breaking exciting, new ground in diverse disciplines such as biochemistry, physiology, material design and paleogeochemistry. Such studies address different levels of organization from the biomineral to the organism. To push the frontiers of understanding, new innovative approaches are being used to improve the culturing of biological material from cell to colony, and in the analysis of calcification processes. Among these are molecular and proteomic approaches; physiological techniques such as Ussing chambers, microelectrodes and in vivo confocal imaging; and geochemical or material science techniques including Raman spectroscopy, secondary ion mass spectrometry (SIMS), nuclear magnetic resonance spectroscopy (NMR), cryo-scanning electron microscopy (SEM), laser-ablation techniques and synchrotron based x-ray diffraction or scattering microscopy. This session welcomes presentations that concern investigations applying these and other innovative approaches with or without classical techniques (buoyant weight, alkalinity anomaly, radioactive isotopes) that show the potential to shed new light into the processes driving calcification and growth. Description of the advantages and drawbacks/limitations of the techniques are also welcome. Corals are the focus of this session, however we also welcome presentations concerning other calcifying organisms associated with coral reefs.

How do new insights into biomineralization help us understand the reef calcification response to global climate change?
Corals, algae, bivalves, foraminifera and microbes all calcify and build the reefs that are vital to marine ecosystems yet many of the mechanisms and processes underlying biomineralization remain poorly understood. Calcifying organisms are particularly vulnerable to ocean warming and acidification, potentially reducing the socioeconomic benefits of ecosystems reliant on these taxa. Using novel tools and instrumentation, mechanisms of biomineralization are being elucidated at increasingly finer temporal and spatial scales. This session focuses on present knowledge on the biological and environmental control of biomineral deposition in marine calcifiers, covering recent advances in understanding structural, biogeochemical, molecular, and physiological aspects of biomineralization. We welcome contributions from researchers studying biomineralization using a diverse range of techniques including molecular and genetic studies, laboratory culturing, microscopy, nuclear magnetic resonance, pH and ion sensors, skeletal geochemistry and field studies. We are especially interested to hear about newly developed tools as well as well-established protocols used in a novel way. Broadly, we seek to better understand the effects of biotic and abiotic constraints on mineral formation and preservation, and how these translate to persistence of the ability to calcify under potentially detrimental conditions of increased sea surface temperature and nutrient loading and decreased ocean pH. This cross-discipline focus will improve the understanding of all attendees of the fundamental mechanisms of biomineralization and its response to global change.

Sebastian Ferse¹, Christina Hicks², Marleen Schutter ², Colette Wabnitz ^3
1 Leibniz Center for Tropical Marine Research (Bremen, Germany)
² Lancaster University (Lancaster, UK)
³ University of British Columbia (Vancouver, CAN)

This open session presents all contributions related to Theme 8, which are not covered by 8B.

Annet Pauwelussen¹, Aída Sofía Rivera Sotelo^2
1 Wageningen University (Wageningen, The Netherlands)
² University of California, Davis (Davis, CA, USA)

In recent years people from a range of disciplines and societal backgrounds have joined discussions and practices of coral protection and rehabilitation. Beyond the natural sciences, the precarious state of coral reefs has become a matter of concern to anthropologists, fishers, indigenous communities, artists, entrepreneurs and many others. The realisation is taking hold that effective and equitable ways of protecting and caring for corals requires the building of alliances across disciplines and societal groups in ways receptive to differences in how people understand and relate to nature and the sea. As a consequence, interdisciplinary and participatory initiatives to conserve or rehabilitate corals bring together different ways in which people know, define, value and imagine corals, and care. How can we understand and build on such complexity in a productive and equitable way? How to build alliances across cultural, epistemological or ontological difference that foster dialogue on how to protect and care for coral reefs? The social sciences could engage theoretically and empirically with concepts, theories, methods and storytelling helping to establish such collaboration in a way responsive to diversity and reflective of structural asymmetries in marine conservation. In line with marine studies in anthropology, Science and Technology Studies and social geography, among others, possible questions to explore are: What and how are the corals we care for? How do we think and imagine their pasts and futures? How is this informed by the conditions of our disciplines, our field sites, colonial legacies and our basic notions of reality and ethics? And how does this affect the kinds of care, management, conservation and rehabilitation measures that are elicited into future reefs? This panel calls for proposals that think about these questions, through theoretical contribution, methodological reflection and case studies.

Christian Wild¹, Christian Voolstra², Selma Mezger¹, Svea Vollstedt^1
1 University of Bremen (Bremen, Germany) 
² University of Konstanz (Konstanz, Germany)

This open session presents all contributions related to Theme 9, which are not covered by the below specialised sessions.

Aaron MacNeil¹, Nicholas Graham², Michelle Devlin^3
1 Dalhousie University (Halifax, Canada)
² Lancaster University (Lancaster, UK)
³ CEFAS Lowestoft (Lowestoft, UK)

Climate change is emerging as a major determinant of coral reef persistence, yet pervasive threats such as poor water quality and overfishing continue to cause widespread reef decline. While climate change itself is beyond any single jurisdiction, actions on local disturbances have the potential to substantially influence coral reef processes, and thus responses to and recovery from climatic threats. In this symposium we are interested in whether local management of ecosystem characteristics - ecosystem functioning, community structure, and responses through time - can moderate climate-driven reef degradation. We are interested in experimental and observational examples where local impacts do not moderate reef responses to climate change, and examples where mitigation of local impacts has improved reef resistance, recovery, or both.
Potential ideas of interest include:
- Is local driver management redundant in the face of climate change?
- Can changes in water quality mediate coral reef responses to climate change?
- What levels of fishing pressure, or types of management, determine continued ecosystem functioning?
- What are the responses and resilience of interconnected coastal systems including coral reefs, seagrasses, and mangroves?
- Do fishing and water quality interact to determine ecosystem responses to climate change?
- Can key functional groups (effect traits) be enhanced through managing local drivers?
- What novel approaches (co-management, gear exclusions, eDNA, remote sensing, modelling) can we learn from to help manage local pressures on reefs?
We also welcome theoretical or conceptual talks that highlight new or emerging ideas concerning multi-scale, multi-threat futures for coral reef ecosystems.

Deron Burkepile¹, Nina Schiettekatte², Sébastien Villéger³, Jacob Allgeier^4
1 University of California Santa Barbara (Santa Barbara, CA, USA)
² Université de Perpignan (Perpignan, France)
³ Université de Montpellier (Montpellier, France)
⁴ University of Michigan (Ann Arbor, MI, USA)

Coral reefs are highly productive, biodiversity hotspots. Ever since the first descriptions of reefs by Charles Darwin, scientists have pondered over how such a productive system can thrive in an oligotrophic environment. One key to ecosystem function on reefs appears to be a very efficient recycling of nutrients by reef-dwelling animals such as fishes, sponges, and other benthic invertebrates. These consumer-derived nutrients can impact coral growth and physiology, benthic community dynamics, and reef-wide nutrient cycling. Yet, severe over-harvesting, habitat degradation, pollution and climate change may fundamentally change the role of animals in nutrient cycles on reefs. For example, the ongoing defaunation of the oceans likely results in a decrease in nutrient storage and supply by animals as well as a fundamental change in the elemental stoichiometry (ratio of nitrogen and phosphorus) of nutrient supply. These alterations in the delivery of consumer-derived nutrients may fundamentally impact key ecosystem process and cascade down to impacting coral health. However, the ideas around animals as important sources of nutrients on coral reefs is a rapidly developing field with many questions yet to be answered. For example, how can we better quantify the impact of animals on nutrient fluxes in coral reefs? How will climate change affect the impact of consumer-derived nutrients on corals? Will increasing human-derived nutrients alter the impacts of consumer-derived nutrients on reefs? How do changes in benthic communities impact the fate of consumer-derived nutrients? This session will bring together researchers from various fields working on the quantification of nutrient cycling to fill in gaps about how the role of consumers in nutrient fluxes will evolve on coral reefs in the Anthropocene.

David Hughes ¹, Andrew Altieri ², Michael Kuhl³, Maggie Johnson⁴, Adrienne Correa^5
1 University of Technology Sydney (Sydney, Australia)
² University of Florida (Gainesville, Fl, USA)
³ University of Copenhagen (Copenhagen, Denmark)
⁴ Smithsonian Tropical Research Institute (Florida, USA)
⁵ Rice University (Houston, TX, USA)

Ocean deoxygenation is a global phenomenon, with dissolved O₂ changing more dramatically than any other environmental variable in recent decades. Research has highlighted the detrimental impact of hypoxia (low dissolved O₂) within temperate coastal systems, identifying ecosystem thresholds, or "tipping points" beyond which catastrophic loss of productivity and biodiversity occurs. Yet, the effect of hypoxia on tropical coral reefs has, surprisingly, been almost entirely overlooked relative to thermal stress and ocean acidification. This is despite historical evidence implicating hypoxia as a key factor contributing to mass extinctions of reef organisms, and transient gaps in reef formation over geological timescales. How hypoxia broadly impacts coral reef taxa is largely unknown, including the potential for acclimation or adaptation, and thus predicting how deoxygenation will shape the future form and functioning of coral reefs is currently not possible to currently resolve. In this session we will consider presentations that address how we can begin to define hypoxia stress within coral reef ecosystems and how and when it occurs. For example, how do hypoxia thresholds vary across key coral reef taxa? Is environmental history a key factor determining hypoxia resilience? What physiological and genetic mechanisms are responsible for conferring hypoxia tolerance to coral reef organisms? Do microscale habitats (e.g., the O₂ microenvironment) play a key role in mitigating hypoxic stress? Can we disentangle the effects of hypoxia from co-occurring stressors, e.g., temperature and pH? Are urbanised and deep-water tropical reefs particularly vulnerable to deoxygenation events? Can we develop predictive capacity to identify vulnerable taxa or locations most vulnerable to hypoxic stress based on existing empirical data? We encourage submissions that consider all aspects of the hypoxia impacts, from microscale interactions to the wider ecosystem level, aimed at understanding the impacts of low-oxygen stress on coral reef ecosystems and how these can potentially be mitigated by management practices and/or environmental reform.

Katharina Fabricius ¹, Joy Smith¹, Rebecca Albright^2
1 Australian Institute of Marine Science (Townsville, Australia)
² California Academy of Sciences (San Francisco, CA, USA)

Ocean acidification is an insidious and chronic stressor for coral reefs that can be enhanced in coastal waters. In coastal regions and on shallow continental shelves, a number of processes including eutrophication can further elevate CO₂, leading to coastal acidification. Many coral reefs are therefore exposed to both ocean and coastal acidification. While ocean acidification is irreversible at human time scales, coastal acidification may be more amenable to management via water quality improvement strategies. To date, much work has focused on the effects of acidification on future reefs under various CO₂ emission scenarios. Evidence now suggests that some of today's coral reefs are already being substantially altered by these changes in seawater carbonate chemistry. Carbon dioxide dynamics in coral reefs are controlled by high intrinsic rates of production, respiration and calcification, as well as by imports of nutrients and organic matter from external sources, light, and by light and seawater hydrodynamics. Together, these factors expose coral reefs to highly variable and at times extreme carbonate chemistry conditions. This session will bring together new insights into the relevant biophysical drivers and processes of ocean and coastal acidification, and their measured and predicted consequences for present and future coral reef ecosystems. We invite studies focusing on this portfolio of questions, with emphasis on carbonate chemistry variability and trends, on conceptual and empirical findings on their effects ranging from molecular to ecosystems, and on research methods development ranging from biochemical to modelling.

Jessica Reichert¹, Maren Ziegler¹, Mia Hoogenboom^2
1 Justus Liebig University (Giessen, Germany)
² James Cook University (Townsville, Australia)

Tropical reef systems are rapidly transitioning to an era of increasing anthropogenic impacts. In particular, the pollution with plastic material has been identified as an emerging threat to coral reefs. Growing quantities of large plastic objects wash up on tropical shores and also affect coastal marine organisms. In addition, these large plastic objects undergo fragmentation into micro- and nanoplastic particles in exponential quantities. However, little is known about plastic concentrations of different sizes and types in reef ecosystems and their consequences for the organisms inhabiting coral reefs. More thorough observations of plastic distribution patterns in time and space are needed to understand this rapidly developing threat to coral reefs. Further, impact assessment studies addressing the biological consequences for reef organisms are necessary to evaluate the potential impact of plastic pollution and to estimate its interactive effects with other anthropogenic stressors. This requires broad assessment of the organisms' responses to plastics under realistic or projected pollution levels. This session aims to set up a platform for discussion of the potential hazards of plastic pollution from the macro- to the micro- and nanoscale. We invite contributions from diverse fields including biology, oceanography, and chemistry that document and quantify plastic pollution in coral reef organisms and their surrounding environment, as well as experimental approaches that investigate the biological responses of coral reef organisms to plastic pollution. The overarching aim of this session is to provide a synthesis of past and perspective on future research priorities on plastic pollution in coral reefs.

Katie Shamberger ¹,  Kristen Davis², Andrea Kealoha³, Andrew King^4
1 Texas A&M University (College Station, TX, USA)
² University of California, Irvine (Irvine, CA, USA)
³ University of Hawaii (Maui, HI, USA)
⁴ University of Melbourne (Victoria, Australia)

Open-ocean waters flow onto coral reefs, supplying reef ecosystems with food, nutrients, heat, energy, and the chemical components that fuel calcification. The initial conditions of adjacent open-ocean surface waters strongly influence coral reef ecosystem health and functioning. For example, rising temperatures and declining pH in the open ocean are sparking mass coral bleaching events and driving reductions in ecosystem calcification rates. Circulation patterns on and off reefs influence larval dispersal and recruitment, thereby playing a key role in population connectivity and reef recovery following major disturbances. Upwelling of deep, cool waters via internal waves or the interaction of currents with topography can provide intermittent refuge to help mitigate thermal stress. Offshore biological productivity impacts the delivery of inorganic and organic nutrients that serve as critical energy sources for biological processes within coral reef ecosystems. Yet, once on shallow reefs, the open-ocean source waters can be dramatically altered by physical, chemical, and biological processes. Therefore, understanding coral reef ecosystem sensitivity and resilience to climate change requires studies focused on the large-scale oceanography outside the reef, small-scale dynamics within the reef, and interactions between the two. This interdisciplinary session invites observational, laboratory, and modeling-based studies investigating connections between coral-reef and open-ocean processes now and in the future. These processes may include, but are not limited to, ocean acidification and warming; open-ocean productivity and nutrient cycling; and regional and local circulation and physical phenomena. We also encourage submissions aimed at identifying coral reefs whose oceanographic setting provides inherent resilience to climate change, and are therefore top candidates for conservation efforts.

Marji Puotinen¹, Nicholas Wolff², Manuel Gonzalez Rivero³, Joshua Madin^4
1 Australian Institute of Marine Science (Crawley, Australia)
² The Nature Conservancy (Arlington County, VA, USA) 
³ Australian Institute of Marine Science (Townsville, Australia)
⁴ University of Hawaii (Honolulu, HI, USA)

Coral reefs face an existential threat from climate change, most notably from increasingly frequent and severe thermal stress (1). This is exacerbated by damage from other disturbances including tropical cyclone (hurricane) waves (2). While we cannot prevent cyclones now or in future, understanding how their likely frequency and severity varies (and will vary) across the world's reefs is vital to ensure conservation efforts like reef restoration are spatially allocated for maximum benefit (3). Each instance of reef restoration can only be deployed over a limited area due to logistics and cost constraints. Such efforts could be wasted if concentrated on reefs likely to be damaged very frequently by cyclone waves. Despite the importance of this, considerable advances in our knowledge and ability to assess how cyclones damage reefs are not widely known - the most recent review paper on this topic was published in 1994 (4). For example, we've since learned that cyclones can sometimes 'help' reefs by cooling SST during times of escalated thermal stress (5, 6, 7), that the size and longevity of a cyclone can be just as important as its intensity in determining the likelihood of reef damage (8), and that we can predict structural vulnerability of corals based on an index of their shape (9) with important ecological consequences (10). This session would aim to: 1) highlight our current state of knowledge about cyclones and how they interact with other stressors to impact coral reefs, and 2) explore how best to target future cyclone-reef field work and research for maximum benefit to spatial targeting of conservation efforts.
1: Hughes et al 2017 Nature; 2: Cheal et al 2017 Glob Change Biol; 3: Beyers et al 2018 Cons Lett; 4: Harmelin-Vivien 1994 Jrl Coastal Res; 5: Manzello et al 2007 PNAS; 6: Eakin et al 2010 PLoS One; 7: Carrigan & Puotinen 2014 Glob Change Biol; 8: Puotinen et al 2016 Sci Rep 9: Madin & Connelly 2006 Nature; 10 - Madin et al 2014 Ecology Letters.

Kristen Brown ¹, Tyler Cyronak², Keisha Bahr³, Nyssa Silbiger ⁴, Steve Doo ⁴, Robert Nowicki^5
1 University of Queensland (Brisbane, Australia)
² Nova Southeastern University (Dania Beach, FL, USA)
³ Hawaii Institute of Marine Biology (Kaneohe, HI, USA)
⁴ California State University, Northridge (Northridge, CA, USA)
⁵ Mote Marine Laboratory (Summerland Key, FL, USA)

The two original sessions below have joined here:

Beyond single-species experiments: how do marine populations, communities, and ecosystems respond to global change?
Global anthropogenic change threatens the ability of coral reefs to maintain ecosystem structure and function. Thermal stress events leading to mass coral bleaching are becoming more frequent and severe on tropical coral reefs while ocean acidification is projected to intensify, impacting the ability of reefs to calcify and maintain net calcium carbonate accretion. Traditionally, studies have focused on understanding the response of individual reef organisms to environmental change. While these species-level studies provide valuable information, there is a growing need to focus our efforts on ecosystem-level dynamics to better understand the effects of anthropogenic change on the structure, function, and recovery of coral reefs from a systems perspective. This session invites presentations that focus on the effects of environmental change on coral reef populations, communities, and/or ecosystems. These studies can include a range of approaches including: (i) mesocosm and in situ experimental studies, (ii) techniques such as eddy covariance and benthic boundary layer approaches that can enhance our understanding of community level function in situ, (iii) observations of community structure and ecosystem function across natural environmental gradients (i.e., carbon dioxide seeps) and thermal stress events, (iv) ecosystem models, or (v) innovative approaches to scaling up coral reef research across ecologically relevant scales. Research efforts at the scale of populations, communities, and ecosystems will help build more realistic representations of the environmental tolerances of coral reefs in the future. This new knowledge can then be used to identify the most effective policies, management strategies, and conservation techniques for the maintenance and recovery of reef ecosystem function into the future.

How do organismal responses scale to ecosystem processes?
Current predictions of how coral reef ecosystem processes (e.g. community metabolism) will be altered in projected climate change conditions (e.g. warming, acidification, hypoxia, nutrification etc.) are largely based on laboratory and field experiments that identify sensitives of individual coral reef organisms to various physicochemical parameters. However, recent syntheses and studies suggest that scaling from individual measurements to ecosystem processes on coral reef ecosystems is not linear, and that accurately determining how coral reefs will respond to climate change hinges on a further understanding of scaling processes. The proposed session aims to highlight studies that focus on bridging the gap of understanding how individual measurements scale to ecosystem processes. Contributions to this session are invited on all aspects of furthering understanding of scaling processes, which include but are not limited to studies on modulation of responses to altered environmental conditions (e.g., climate change, eutrophication, etc.) through species interactions, conspecific genotypic variation in responses to climate change stress, experiments that link measurements of individual components to ecosystem measurements. We welcome both empirical and theoretical studies.

Jasper de Goeij¹, Verena Schoepf², Manuel Aranda Lastra ³, Ulisse Cardini⁴, Adriana Verges ^5
1 University of Amsterdam (Amsterdam, The Netherlands)
² University of Western Australia (Perth, Australia)
³ KAUST (Thuwal, Saudi Arabia)
⁴ Stazione Zoologica Anton Dohrn (Napoli, Italy)
⁵ University of New South Wales (Kensington, Australia)

This open session presents all contributions related to Theme 10, which are not covered by the below specialised sessions.

Timothy Ravasi¹, Iliana Baums², Jose M. Eirin-Lopez³, Gergely Torda^4
1 Okinawa Institute of Science and Technology (Okinawa, Japan)
² Pennsylvania State University (State College, PA, USA)
³ Florida International University (Miami, Fl, USA)
⁴ ARC Centre of Excellence for Coral Reef Studies (Townsville, Australia)

Anthropogenic activities alter the climate and ecosystems globally, making it increasingly challenging for organisms to keep pace with the associated rapid ecological changes in their environment. Coral reefs are particularly affected due to the sensitivity of the sessile or sedentary organisms that form the backbone of these ecosystems. The worldwide decline of coral reef ecosystems made it imperative to better understand the mechanisms underpinning evolutionary processes and how they influence and are influenced by demographic processes, population connectivity, interspecific interactions, and the interaction of species with their abiotic environment. These ecological processes are important in directing and constraining evolutionary processes, and in turn evolutionary change greatly affects (meta)population trajectories. This session aims to bridge the gap between the fields of coral reef ecology and evolution, bringing together ecologists, evolutionary biologists, physiologists, molecular biologists, microbiologists and modelers to brainstorm about how ecological changes associated with climate change will influence the adaptive capacity of (meta)populations of coral reef organisms. In addition, special emphasis will be put on discussing the various avenues for adaptation and acclimatization of coral reef organisms, including modifications in the genome, epigenome and microbiome. This session aims to not only contribute novel data but also robust experimental designs, innovative theories and synthesis talks to drive research addressing acclimatization, adaptation and metapopulation evolution. We are confident this session will be of interest for a wide audience among participants of the ICRS 2020, specifically (but not limited to) those interested in coral reef ecology and evolution, reef-omics, coral conservation, coral epigenome, and microbiome.

Ulisse Cardini ¹, Adriana Vergés^2
1 Stazione Zoologica Anton Dohrn (Napoli, Italy)
² University of New South Wales (Kensington, Australia)

Oceans are getting warmer, and subtropical and temperate seas worldwide increasingly experience the intrusion of tropical species, a process called 'tropicalization'. Tropicalization has already led to profound transformations in some ecological communities, including detrimental effects on temperate algal and gorgonian forests, as well as poleward shifts in tropical seagrasses that compete with native counterparts. Ultimately, a range of important ecosystem services may be affected. Novel approaches to address this problem are needed. For example, since it is now clear that marine organisms are not self-complete but rather form with their associated micro-organisms entities called holobionts, it is paramount to investigate the role played by microbial partners in the ability of species to either adapt to warmer conditions or shift their distribution to stay within a preferred thermal range. The Mediterranean Sea, the widest marine warm-temperate region in the world, represents a large scale natural experiment for observation of the role of holobionts in the tropicalization of marine ecosystems. Other hotspots, such as Japan, Australia and Brazil, are equally relevant and testify to the global scale of the phenomenon. This multidisciplinary session will serve as a platform to report on the biology and ecology of high latitude reefs and tropical-temperate transition zones, where the ecological consequences derived from the intrusion of tropical species are likely to manifest first, and on the role that microbes may play in adaptation to non-native environments. More generally, the session will focus on the ecological impacts of tropical organisms in subtropical and temperate systems and the associated shifts in species interactions and ecosystem functioning.

Andrea Grottoli ¹, Robert Toonen², Robert van Woesik³, Ann Marie Hulver ¹, Rowan McLachlan ^1
1 The Ohio State University (Columbus, OH, USA)
² Hawaii Institute of Marine Biology (Lillipuna, HI, USA)
³ Florida Institute of Technology (Melbourne, Fl, USA)

Coral bleaching is responsible for massive coral loss globally. As climate change continues, the frequency and intensity of coral bleaching will increase. Yet some corals survive thermal stress events, and either do not bleach or bleach and recover. In this session we will explore the physiological, biogeochemical, and microbial processes that underlie the vulnerability and tolerance of corals to thermal stress and bleaching. We are particularly interested in the response of corals to multiple stressors, in determining the reaction norms of different coral phenotypes and genotypes across a range of environmental stressors, and in the interrelationships between genotype, phenotype, and environmental factors in determining response characteristics.

Manuel Aranda Lastra¹, Hollie Putnam², Mikhail Matz^3
1 KAUST (Thuwal, Saudi Arabia)
² The University of Rhode Island (Kingston, RI, USA)
³ The University of Texas at Austin (Austin, TX, USA)

The alarming decline of coral reef health worldwide has raised concerns that the rate of global change might outpace the capacity of reef organisms to evolve in response to these threats. In addition to genetic adaptation, which is based on natural selection operating on populations, all organisms are capable of acclimating to environmental change to some extent using environment-driven phenotypic modifications, or “plasticity”, happening at the individual level. These “epigenetic” mechanisms include various molecular processes such as DNA methylation, histone modifications and small non-coding RNAs. These mechanisms can dynamically alter gene expression to better suit different environmental conditions and, at least in theory, could have lasting effects extending beyond the lifetime of a single individual and contribute to the population-level adaptive response in the long term. The study of epigenetic mechanisms as means for reef organisms to adapt to a changing environment is becoming increasingly important for our understanding of coral reef resilience in the context of global climate change. This session will serve as a platform for scientists working on epigenetics in reef organisms to present and discuss their findings, and to introduce this emerging field of study to a broader audience.

Sarah Davies ¹, Carly Kenkel², Ross Cunning ³, Jeremie Vidal-Dupiol ^4
1 Boston University (Boston, Ma, USA)
² University of Southern California (Los Angeles, CA, USA)
³ John G. Shedd Aquarium (Chicago, IL, USA)
⁴ Université de Montpellier (Montpellier, France)

Plasticity is the ability of an individual to produce a range of phenotypes in response to environmental variation. Understanding the drivers and consequences of phenotypic variation is critical for predicting organismal responses to environmental change. Many marine organisms encounter environments favoring different phenotypic optima, however the relationship between the direction and magnitude of plasticity and fitness (survival and/or reproduction) remains unknown. While prior experience can significantly alter subsequent responses to stress, the importance of time-lags between cue and response, as well as the capacity for reversibility remain unexplored. The mechanisms giving rise to plasticity are also unresolved, but may include genetic and non-genetic mechanisms that can function at different levels of the holobiont (an organism and its associated microbiota). Given that environments are rapidly changing, phenotypic plasticity that may have previously been essential to efficiently respond to certain environments might become adaptive. Finally, for certain taxa, such as corals, understanding how plasticity shapes responses to novel reef environments will be critical to the success of applied restoration activities. This session is focused on understanding the role(s) that plasticity might play in acclimatization or adaptation of reef organisms to environmental change.

Celia Schunter¹, Rohan Brooker², Sally Keith ^3
1 The University of Hong Kong (Hong Kong, HKSAR)
² Deakin University (Victoria, Australia)
³ Lancaster University (Lancaster, UK)

Human impacts on marine ecosystems are increasingly apparent and severe, with climate change, coastal development, and rapid exploitation occurring at the expense of habitat quality and biodiversity. For coral reef organisms, behavioural responses to environmental change can influence vulnerability; while species or individuals that can modify their behaviour to exploit new conditions may persist those that are inflexible may decline. Behavioural adjustments to rapid change can therefore have broader ecosystem-level effects, mediating population structure and evolution through shifts to key processes such as mate choice, dispersal, and migration. However, while some alterations can be beneficial, others are maladaptive, or have varying effects over the short and long-term. Given the complex relationship between behaviour and environmental change, it is critical that we determine the environmental and biological factors that influence behaviour under both current and future conditions. This includes examining the neurological and molecular mechanisms underlying behaviour and their adaptive potential, the impact of long-term environmental change on behaviourally mediated processes and ecosystem function, and how behaviour can be harnessed to increase ecosystem resilience. To this end, this multidisciplinary symposium will draw together expertise from a range of fields to examine the links between behaviour and environmental change. It will contribute to a greater, cross-disciplinary, understanding of how behavioural adjustments occur with changing environmental conditions, how these changes affect the ecology within coral reef ecosystems, and increase our capacity to develop informed conservation and management responses.

Peter J. Schupp¹, Jasper de Goeij², Verena Schoepf ³, Petra Visser ^2
1 University of Oldenburg (Oldenburg, Germany)
² University of Amsterdam (Amsterdam, The Netherlands)
³ University of Western Australia (Perth, Australia)

This open session presents all contributions related to Theme 11, which are not covered by the below specialised sessions.

Petra Visser ¹, Erik Meesters², Lisa Becking³,
¹ University of Amsterdam (Amsterdam, The Netherlands)
² Wageningen University and Research (Den Helder, The Netherlands)
³ Wageningen University and Research (Wageningen, The Netherlands)

Benthic cyanobacterial mats increase worldwide on coral reefs. Benthic filamentous cyanobacteria are common on reefs, but the cover and density of mats has increased the last two decades with up to 30% on many present day reefs. Their presence in the past was more concealed e.g. as subgroup in algal-dominated turfs on hard bottom substrates. Nowadays you can find dense filamentous mats growing on sand, bare hard substratum, macroalgae as well as next to and on live corals. Mats appear to be dominated by common cyanobacterial species such as Lyngbya majuscule, Oscillatoria sp. Moreover, mats can be toxic and their palatability is overall low. Putative drivers of mat development are pollution (eutrophication by sewage, freshwater flooding, iron input, degrading reefs) and temperature. Calm hydrodynamic conditions might be required for the establishment of mats. The local wax and wane of mats tends to be highly variable in space and time, which casts doubt on the role of different drivers. Interesting is the not well-understood sudden disappearance of mats. Is this due to e.g. grazing by herbivores, microbial degradation, burial or dislodgement and transport? Mats are known for their fixation of nitrogen and release of bioavailable nitrogen and dissolved organic matter (OM) during day and night. Mats appear to be the strongest OM releasers of all benthic primary producers per unit surface area of reef. As a consequence of the consortium metabolism, mats can become anoxic during the night. Pelagic microbes stimulated by the OM release may further contribute to hypoxic conditions in the benthic boundary layer. Such hypoxic conditions may persevere in stagnant water under, within and above dense mats during day and night which may be harmful or deleterious to corals in the mat-coral interaction zone and interaction with other benthic reef organisms (macroalgae, sponges, crustose coralline algae). Little is known whether toxins excreted by the mats may also deter settlement of larvae and harm neighbouring benthic reef organisms. We welcome contributions on distribution, wax and wane of mats, chemical fluxes in and out of mats, toxicity, grazing and molecular ecology including metagenomics of mats and interactions between mats and other benthic organisms.

Christine Ferrier-Pagès ¹, Sergio Rossi², Yehuda Benayahu³, Janie Wulff ⁴, Christine Schönberg^5
1 Centre Scientifique de Monaco (Monaco)
² University of Salento (Lecce, Italy)
³ Tel Aviv University (Tel Aviv, Israel)
⁴ Florida State University (Tallahassee, FL, USA)
⁵ University of Western Australia (Crawley, Australia)

The two original sessions below have joined here:

Shift in scleractinian dominated reefs - are we facing new winners - octocorals, sponges and macroalgae?
Coral reefs worldwide have suffered significant declines in coral cover and species diversity, due to the combined effects of global change, pollution and diseases, among others. In many areas like the Caribbean or the Great Barrier, the role of stony corals as architects of the ecosystem is substituted by other three-dimensional alive structures. For example, these changes are often associated with shifts from hard coral-dominated communities to macroalgae, sponges or octocoral-dominated communities. During the last decades, a huge effort has been made to understand scleractinian coral distribution or demography, reproduction or growth, physiology or symbiotic patterns, but relatively little is known on the autoecology and the ecosystem role of the other benthic groups and on their response to environmental perturbations. This clearly limits our capacity to forecast and understand future changes in the seascape of tropical systems. Our session will focus on the structure and function of octocoral, sponge and macroalgal communities, in coral reef ecosystems and how they are affected by the ongoing environmental changes. We invite contributions that examine the ecology, life history, physiology, trophic ecology and symbiotic relationships of these benthic groups and the mechanisms underlying their resilience under environmental and anthropogenic stress. We will be encouraging submissions across all geographic regions, where octocorals, sponges and macroalgae play an increasing role in the ecosystem. We will also encourage young participants to contribute this session.

Sponges on coral reefs: how can we reconcile contradictory reports on controls, population and community dynamics, and functional roles?
Controversy over sponge functional roles and how sponge populations are controlled on coral reefs has become polarized and, given the many key roles played by sponges, it seems important to see how we can reconcile contrasting views of sponge influences and dynamics. Contrasting reports that: a) sponges are overwhelming corals and reefs vs. suffering mass mortalities; b) sponges are controlled by spongivores vs. by picoplankton and nutrient availability; and c) sponge effects on corals are damaging vs. enhancing, result in opposing conclusions that impede clear predictions of future states. Potentially profound reciprocal influences of sponges and the water column on each other, as well as of sponges and corals on each other, impel increased attention to focused studies of sponge ecology. Sponges must also be added to monitoring, conservation, restoration, and management plans, but the most useful and efficient ways to do this require thoughtful conversation, as standard coral reef techniques must be modified to take into account how sponges differ from corals, i.e., an order of magnitude greater species diversity, living tissue throughout their 3-dimensional bodies, disintegrating upon death rather than leaving behind a skeleton, capable of inhabiting cryptic spaces where evaluation is difficult, and playing a greater variety of ecosystem functional roles. We hope to facilitate movement from polarized debate to discussion of circumstances under which contrasting results are obtained. Are contrasting reports due to focus on different species? generalization from too few or unusual species?  different metrics and techniques used? field sites varying in key aspects? temporal and spatial scales dissimilar?  We will provide a forum for presentation and discussion of new data to address the balance between bottom-up vs. top-down controls on sponges, positive vs. negative functional roles of sponges, and increasing vs. decreasing populations of sponges.

Alastair Harborne ¹, Mary Donovan ², David Kochan¹, Matthew Mitchell³, Alice Rogers^4
1 Florida International University (Miami, Fl, USA)
² University of California, Santa Barbara (Santa Barbara, Ca, USA)
³ NYU Abu Dhabi (Abu Dhabi, United Arab Emirates)
⁴ Victoria University (Wellington, New Zealand)

The multiple threats degrading coral reefs are widely recognized as reducing coral cover, and consequently reef complexity and structure. Complexity is critical for maintaining diverse and abundant fish assemblages because of the need of many species to use reef structure for nesting, foraging, spawning, refuge from predators, and to maintain themselves in high-flow environments. Consequently, reef structure underpins the key ecosystem service of protein provision, and loss of complexity is having profound impacts on fish and fisheries. However, despite the well-established links between fish and structure, many questions remain including how structure mediates reef food webs (e.g. consumptive and non-consumptive predator-prey interactions and trophic structure), affects inter- and intra-specific competition, changes fish behavior and physiology, and impacts fish catches and profits. For example, there are few data on the multiple impacts of reduced reef complexity on prey species (e.g. earlier detection of predators) and predators (e.g. altered hunting efficiency), and the implications for their demographics and ultimately catchable biomass. Answering such questions has recently benefited from new ways to explore and quantify reef structure at multiple scales, particularly through three-dimensional digital reef reconstructions that can now be undertaken with simple cameras and off-the-shelf software. This session aims to bring together an interdisciplinary series of talks and posters that address any aspect of the relationship between reef structure and fish and fisheries. We welcome submissions on any topic related to fish and reef complexity, including studies that address characterizing reef complexity, consider the effects on fish ecology, demography, behavior, or physiology, examine the impacts of reduced reef structure on fisheries and human food security, and suggest conservation initiatives including reef restoration and artificial reefs to increase structure.

Brigitte Sommer ¹, David Booth², Yohei Nakamura³, Maria Beger^4
1 The University of Sydney (Sydney, Australia)
² University of Technology Sydney (Sydney, Australia)
³ Kochi University (Nankoku, Kochi, Japan)
⁴ University of Leeds (Leeds, UK)

Climate change is markedly transforming marine ecosystems as differential species responses to warming, species migrations and species abundance changes lead to altered dominance patterns, novel species configurations and interactions. These changes are already occurring in many systems, including tropical coral reefs post bleaching and along biogeographic transition zones, where tropical and temperate species overlap at their range limits. Nevertheless, the dynamics and mechanisms driving these changes and how they affect ecosystem function are poorly understood. Multi-taxon studies are therefore critically needed to understand the links between community composition, species interactions and environmental conditions and to predict future trajectories for marine ecosystems. We invite presentations that focus on multi-taxon research (e.g. corals, algae, fish) in tropical-to-temperate systems, from local field experiments to global analysis and ecosystems models. We particularly encourage presentations from high-latitude systems, where species range shifts (e.g. of corals and tropical fishes) and altered species interactions (e.g. altered herbivory patterns) and functions are already transforming ecosystems.

Sebastian Ferse ¹, Annette Breckwoldt ¹, Kirsten Oleson ², Jason Philibotte ³, Marie-Lise Schläppy⁴, Line Bay⁵, Anna M. Addamo ^6,7
1 Leibniz Center for Tropical Marine Research (Bremen, Germany)
² University of Hawaii Manoa (Honolulu, HI, USA)
³ NOAA Coral Reef Conservation Program (Silver Spring, MD, USA)
⁴ UWA/AIMS (Crawley, Australia)
⁵ Australian Institute of Marine Science (Townsville, Australia)
⁶ European Commission, JRC (Ispra, Italy),
⁷ National Museum of Natural Sciences (Madrid, Spain)

This open session presents all contributions related to Theme 12, which are not covered by the below specialised sessions.

Kenneth Anthony ¹, Paul Hardisty¹, Elizabeth Shaver ^2
1 Australian Institute of Marine Science (Townsville, Australia)
² The Nature Conservancy (Arlington, VA, USA)

Decision problems on coral reefs are becoming increasingly wicked. New interventions and management strategies are developing, but reefs are in decline and the window of opportunity to act is closing with climate change. More options, but limited time and a complex but degrading system means more uncertainty. Which choice is risky, safe, beneficial, and for whom? How can reef managers, policy makers and conservation practitioners best tackle this growing decision challenge? This session will bring the best of multidisciplinary, structured decision-making to bear on this problem. Our unifying question will be: what guiding principles should we give decision-makers at different levels? We will address this question for reefs a social-ecological systems with multiple, often conflicting, objectives. We invite contributions from high-level government officials to on-reef conservation practitioner, biologists to economists, behavioural psychologists to systems modellers. Our session will underpin the symposium's theme "Tackling the Challenging Future of Coral Reefs" by bringing clarity and transparency to decision problems and solutions for coral reefs and dependent people. We will work with our speakers to ensure we deliver an integrated and coherent session with clear messages that a diverse audience can benefit from. The session will be interactive, entertaining and engaging. We start with a scene-setting talk with subsequent talks playing directly into the theme laid out by the scene-setter. We hope to end the day with a Public Forum. Here we will showcase a few illustrative, timely decision problems that call for urgent solutions. Contributors, invited experts and the audience will tackle these with the sessions chairs or an invited facilitator, and using the principles developed during the day's session. Lastly, we will invite the contributors to join us in writing a policy-relevant publication based on what we develop during the session.

Tauna Rankin ¹, Supin Wongbusarakum², Juan J. Cruz-Motta³, Nygiel B. Armada^4
1 NOAA (Silver Spring, MD, USA)
² University of Hawaii (Honolulu, HI, USA)
³ University of Puerto Rico (Mayaguez, Puerto Rico)
⁴ USAID Fish Right Program (Philippines)

Coral reef fisheries present a multitude of challenges to conventional fisheries management that focuses on a sectoral perspective and target stocks. These challenges include the high diversity of species, variety of fishing gears and methods, a wide range of coastal resource uses, and degraded states of coastal habitats and species. These factors, combined with limited management resources, lead to notoriously sparse information on the biology and status of stocks and lack of adequate understanding of socio-cultural and economic dependence on these stocks and the supporting coral reef ecosystems. Thus, effective management and conservation requires a more holistic and inclusive approach that addresses the complex and dynamic features of the ecosystems that provide goods and services beyond those of benefit to coral reef fisheries. The concept of ecosystem-based fisheries management (EBFM) has been around for several decades and key strengths include its capacity for multivariable consideration of physical, biological, economic and social interactions in fisheries management areas, through a place-based approach that engages stakeholders. This is an underutilized opportunity that would facilitate an examination of trade-offs as a means to optimize benefits among a diverse set of societal goals and bolster ecosystem resilience. An effective EBFM framework can help managers better plan for changes to coral reef condition and functions, as well as human and ecological communities. Despite the sound principles and benefits of EBFM, its implementation has been limited. This session will share successful approaches and insightful lessons from different countries/regions on how EBFM has been applied, thereby providing guidance as to what it takes to make the successful shift from conventional fisheries management to ecosystem-based management for coral reef-dependent fisheries, even in data-poor areas.

Stacy Jupiter ¹, Kim Falinski², Amelia Wenger^3
1 Wildlife Conservation Society, Melanesia Program (Suva, Fiji)
² The Nature Conservancy (Arlington, VA, USA)
³ The University of Queensland (Brisbane, Australia)

Managing downstream impacts from land-based activities is regarded as an important component of maintaining or restoring coral reef system resilience due to the direct and indirect negative impacts of sediments, nutrients and chemicals on reef organisms. However, it is often difficult to identify where to optimally target land-based management given the complex biophysical and chemical processes that affect the magnitude and geographic fate of land-based pollutants. This session will explore emerging new tools that build the evidence base that catchment management can be effective for improving water quality and reef condition. We will also highlight new innovations in integrated land-sea modelling that enable geographic prioritization of where to target and scale management actions. Presented case studies will showcase empirical and modelled outcomes of catchment management in coral reef social-ecological systems for both reefs (e.g., impacts to benthic cover and reef fish communities) and people (e.g., impacts to livelihoods, health and well-being). We will also discuss the imperative for transdisciplinary collaboration to better understand pathways of impact and link scientific evidence to management practice.

Melanie McField¹, Lisa Carne², Anastasia Banaszak³, Nadia Bood^4
1 Healthy Reefs Initiative, Smithsonian Institution (Florida, USA)
² Fragments of Hope (Belize)
³ National Autonomous University of Mexico (UNAM) (MC, Mexico)
⁴ World Wide Fund for Nature (WWF) (Belize)

Coral reefs around the world are facing unprecedented levels of stress due to global pressures like climate change and ocean acidification, as well as regional and local stress factors like pollution and overfishing. Significant conservation and management efforts are underway but are struggling match the scale and speed of the widespread potential ecosystem collapse facing reefs. Although there has been much progress in the science of conservation and restoration of coral reefs and, including key ecosystem functions and services, most activities around the globe have not reached ecosystem-scale. There are many reasons for this including lack of financing, human capacity, political will or the required legal framework. This session will therefore invite stakeholders from areas and projects that are on their way towards scaling success or have achieved large-scale successes in coral reef preservation to analyze the enabling conditions that have made the range of their efforts possible as well as the limiting factors or restrictions they had to overcome. The session will follow the main thematic lines of:
- Networking and collaborations, including different actors and across sectors
- Strengthening political will and influencing a beneficial legal environment
- Good governance for reef restoration and conservation
- Securing long-term, sustainable financing for coral reef conservation and restoration
Thus, it will identify best as well as worst practice examples and serve as a platform to foster mutual learning and exchange. The identification of major obstacles to overcome and the needs in communicating coral conservation needs to a broad range of stakeholders will complement the discussions.

Katja Mintenbeck, Elvira Poloczanska
IPCC Working Group II TSU c/o AWI Bremerhaven (Bremen, Germany)

According to two recent assessments by the Intergovernmental Panel on Climate Change (IPCC), the Special Report on Global Warming of 1.5°C and the Special Report on the Ocean and Cryosphere in a Changing Climate, warm-water coral reefs are already at high risk and are projected to transition to very high risk even if global warming is limited to 1.5ºC. Not only do coral reefs support a large and unique biodiversity but over 500 million people depend on coral reefs for livelihoods and wellbeing. “Tackling the Challenging Future of Coral Reefs” including their dependent/associated human communities and industries in the light of global climate change requires more than just stocktaking of accumulated knowledge - it requires anticipatory actions, changes in public awareness and behaviour, and shifts in global policy. Science can significantly contribute to enabling and supporting informed and ambitious decision-making by (1) providing information that is relevant for climate change decision-making, in particular in regard to consequences, response options and solutions, (2) communicating this information in a concise and understandable way, and (3) stimulate new thinking and innovative actions, even under uncertainty. Science and Policy/decision-making are often disconnected due to a lack of a common language, but there are ways to bridge between the two. As an example, policy-focussed assessments that distil scientific knowledge into comprehensive and understandable reports, such as the assessment reports provided by the IPCC and the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), connect science and policy and raise broad attention. We invite scientists, authors of assessment reports, experts working at the science-policy interface, practitioners, decision-makers and science communicators to present and discuss their ideas on how to best communicate scientific findings, how to stimulate new ways of thinking and action, and what is needed from a decision-makers perspective and what makes scientific findings “policy relevant”, in the context of tackling the challenging future of coral reefs.

Sebastian Ferse ¹, Annette Breckwoldt¹, Heath Kelsey ^2
1 Leibniz Centre for Tropical Marine Research (ZMT) (Bremen, Germany)
² University of Maryland Center for Environmental Science (Cambridge, MD, USA)

Designing appropriate management approaches that ensure a protection and sustainable use of coral reef ecosystems in light of projected environmental and societal changes requires participatory and transdisciplinary approaches in research and development of management plans. In this session, we want to bring together a range of researchers and practitioners from a broad range of backgrounds to exchange experiences with such approaches and distil lessons learned by comparison across different cases. Potential topics include, but are not limited to:
- participatory research with the aim of gathering actionable results
- the use of alternative scenarios for the co-design of management plans
- integration of natural and social science data in models to develop a basis for policy decisions
- integration of local and traditional forms of knowledge with academic scientific information
- characteristics of suitable fora for interaction and exchange of views
- analyses of participatory processes in policy design
- trade-offs between ecological, socio-economic and cultural targets
- incorporating uncertainty about future social-ecological system configuration in decision-making
Target disciplines range from sociology, humanities, political sciences, social-ecological modelling to legal studies and economics. A final synthesis discussion is envisioned to lead to a review paper (suggested topics: characteristics of suitable formats for co-design of management, use of scenarios for planning, legal enabling conditions and barriers to co-design of management).

Marie-Lise Schläppy ¹, Hugh Posssingham², Line Bay ³, Verena Schoepf^4
1 UWA/AIMS (Crawley, Australia)
² The Nature Conservancy (Arlington, VA, USA)
³ Australian Institute of Marine Science (Townsville, Australia)
⁴ The University of Western Australia (Perth, Australia)

Coral reefs are being impacted by a number of anthropogenic impacts and, in a context of limited resources to fund conservation and restoration projects, difficult decisions must be made about where and when to act. Triage methods such as those used in the medical field, can be used to prioritize conservation and restoration actions to target coral reefs that need it the most or where the action will be most beneficial. In the field of terrestrial ecology, the legitimacy of such methods is being questioned as those in opposition of these methods argue that ecosystems that are not selected for conservation or restoration are effectively abandoned. The proponents of such methods point that the inaction that stems from not making a decision and delaying action often amounts to making a decision that can be deleterious to the ecosystem in need of conservation. In this session, we welcome presentations that address the issue of prioritization of conservation and restoration projects on coral reefs. We invite presentations of case-studies on how prioritization was achieved, theoretical frameworks that may help in decision-making (e.g. novel ecosystem framework, Investment Framework for Environmental Resources (INFFER)) and on which dimensions may be used (e.g. ecosystem services, values linking to human well-being) to underpin those decisions.

Elizabeth Shaver ¹, Elizabeth Mcleod¹, Kenneth Anthony², Jennifer Koss^3
1 The Nature Conservancy (Arlington, VA, USA)
² Australian Institute of Marine Science (Townsville, Australia)
³ NOAA Coral Reef Conservation Program (Silver Spring, MD, USA)

Decades of human impacts and global climate change have devastated the world's coral reefs, with 2017 marking the end of the world's longest, most widespread, and possibly most damaging coral bleaching event in history. To counter the global decline of coral reefs, scientists have called for a move beyond conventional management to a focus on supporting the resilience of coral reefs, dependent people, and economies. Resilience - defined as the capacity of a system to withstand stressors, maintain its structure and function in the face of disturbance, and adapt to future challenges - has been proposed as a guiding framework for coral reef management in an era characterized by rapid global change. However, continued decline of both isolated and intensively managed reefs raises the question of how to best incorporate resilience into management and whether managing for resilience is a viable strategy to protect reefs in the face of climate change. In this session, presentations will provide key insights into the question: what is the evidence base for resilience-based management and where is this field going in the future? This session welcomes oral and poster presentations on cutting-edge reef resilience science, including current and future applications, and identification of new ways to support resilience. Resilience approaches may include, but are not limited to, conventional methods (e.g., herbivore protection, reduction of local threats), restoration interventions (e.g., assisted evolution or colonization, gene editing, supportive breeding), or innovative approaches (e.g., geo-engineering).

Tina Dohna ¹, Maya Pfaff ², Laura Puk ³

¹ Zukunft-Umwelt-Gesellschaft (ZUG) gGmbH
² Deutsche Gesellschaft für Int. Zusammenarbeit (GIZ)
³ World Wide Fund for Nature (Hamburg, Germany)

The rate of coral loss around the world is increasing and coral reefs are faced with an increasing amount of negative impacts. Scientists, conservation practitioners and policy-makers alike are struggling to keep pace and conserve coral reefs. Often coral reef conservation and scientific endeavors are insufficiently linked to achieve the scale and impact that is needed. In order to make measurable impacts, the urgency to strengthen synergies and interlinkages between science and policy will be critical.  Thus, the aim of this session is to provide a global overview of the activities and success stories in coral reef management from all around the world by providing the practitioners themselves with the voice to share their case studies. Together with participants from the scientific realm, civil society and developing agencies key success factors will be analyzed and discussed what remaining challenges are. This session will identify at which level the exchange between science and reef conservation has been successful in the past (best practice examples) and which are the obstacles and challenges to overcome for the future. Furthermore, it will point out where lacks in communication or data exchange have led to setbacks (worst practice exchange) and thereby present a panorama of joint approaches that aimed at or were able to successfully conserve, protect and restore coral reefs and their ecosystem services. The session will present infrastructures, platforms and tools that already exist or would be needed to facilitate and optimize the exchange and cooperation between science and conservation. It will provide a unique opportunity for a dialogue between the scientific community and conservation practitioners, allowing understanding where synergies are and how successful collaboration can be achieved.

Anna Maria Addamo^1,2, Mariagrazia Graziano¹, Francesca Santoro³, Thamasak Yeemin⁴, Vo Si Tuan^5
1 European Commission, JRC (Ispra, Italy),
² National Museum of Natural Sciences (Madrid, Spain)
³ IOC, UNESCO (Venice, Italy)
⁴ Marine Science Association of Thailand (Bangkok, Thailand)
⁵ Institute of Oceanography Vietnam (Nha Trang, Vietnam)

Ocean Literacy has been defined as the understanding of the ocean’s influence on humankind, as well as our own influence on the ocean itself. The main objective is to educate people, offering information and tools that would allow all to make sensible decisions when it comes to the ocean and its resources. The Marine Natural Capital is the ocean’s stock of natural assets, which include living organisms and their habitats, and whence human survival and well-being derive in a wide range of ecosystem services.  While the Blue Economy identifies the economic activities that indirectly and directly use resources from the ocean and the coastal areas, the Sustainable Blue Economy is the joint economy activity based on healthy, resilient and productive marine environments, which include coral reefs. Coastal and island communities highly depend on the ecosystem services provided by coral reefs. Living without coral reefs, whether they are shallow, deep, tropical or cold water will be challenging and prove so. Coral reefs provide resources for fisheries, coastal protection, recreation and tourism, thereby the basis for human’ livelihoods and national economies. Climate change, ocean acidification, unsustainable use, ceaseless rise demand for marine resources, have led to the classification of coral reefs as Vulnerable or severely Threatened Ecosystems. A call for Blue Growth has been globally raised to support sustainable approaches with a hope of reconciling economic development and the conservation of marine ecosystem services. Quantifying coral reef ecosystem services and how society and blue businesses (incl. emerging sectors) can truly benefit from sustainable practices are the core of the session on Coral Reefs and Sustainable Blue Economy.  Ocean communication, ecological goods and services of coral reef ecosystems; community-based management of ecosystem services; economic evaluation of benefits derived from coral reefs; opportunities and risks to business associated to the reef ecosystem and its degradation; challenges and solutions for a sustainable use of coral reefs in the blue economy era. These are some but definitely not all the questions that need to be addressed, in order to assess the various facets of critical value of coral reefs for the sustainable blue economic development of human society.  

Jason Philibotte ¹, Petra MacGowan ², Dana Wusinich-Mendez ¹, Michael Lameier³, Jennifer Koss ^1
1 NOAA Coral Reef Conservation Program (Silver Spring, MD, USA)
² The Nature Conservancy (Arlington, VA, USA)
³ NOAA National Marine Fisheries Service (Silver Spring, MD, USA)

Creating 'communities of practice' for marine managed and protected areas have become a valuable and cost-efficient tool to support coral reef conservation efforts. This relatively new approach to coral reef conservation aims to increase management effectiveness by providing opportunities for local managers and practitioners to share information, expertise, and experience with other network members and access experts to develop and strengthen local management capacity. These social learning networks (Learning Networks) provide institutional capacity and a foundation to maintain standards, raise funds, and manage knowledge over the long-term. While Learning Networks can be classified in two major categories, 1) geographic focus, (i.e. PIMPAC - The Pacific Island Managed and Protected Area Community) and 2) topical focus (i.e. Reef Resilience Network), the primary goal of both is to connect resource managers, provide access to new science and tools, build local capacity, increase management effectiveness, and share knowledge and lessons learned. During the session, representatives from learning networks will present on the various value propositions, governance structures, knowledge exchange activities, limitations, evaluation approaches, and common priorities of learning networks to help answer the question - Do learning networks lead to better local marine management and enhanced coral reef conservation efforts?

Sebastian Ferse¹, Ronald Osinga^2
1 Leibniz Center for Tropical Marine Research (Bremen, Germany)
² University of Wageningen (Wageningen, The Netherlands)

This open session presents all contributions related to Theme 13, which are not covered by the below specialised sessions.

Curt Storlazzi¹, Shay Viehman², Mike Beck^3
1 U.S. Geological Survey (Santa Cruz, CA, USA)
² NOAA (Beaufort, NC, USA)
³ University of California, Santa Cruz (Santa Cruz, CA, USA)

Coastal flooding and erosion affects thousands of vulnerable coastal communities and has resulted in hundreds of billions of dollars in damage during the past decade alone; these impacts are predicted to worsen with continued population growth and climate change. There is growing recognition of the role of coral reefs in coastal hazard risk reduction as they dissipate wave energy and produce and trap sediment on adjacent beaches and thus reduce flooding and erosion. Given these benefits, there is the potential to apply coral reef restoration not only to meet ecological recovery goals (coral species, reef communities), but also to reduce coastal hazards and build coastal resilience to current and future storms. To meet and support these joint objectives, there must be rigorous, quantitative assessments of restoration performance, particularly for risk reduction benefits. This mini-symposium focuses on advancements in understanding the role of coral reefs in hazard risk reduction, including but not limited to (i) quantifying the roles of coral spacing, morphology, and attachment strength in boundary-layer hydrodynamics; (ii) relating coral species morphology, structural complexity, or reef location to change in hydrodynamic roughness or induction of wave breaking for different environmental forcing conditions; (iii) design and siting of reef restoration to best reduce coastal flooding for different reef configurations; (iv) comparison of natural "green" and hybrid "gray-green" infrastructure in relation to ecological and hydrodynamic change; (v) incorporation of ecological connectivity into reef restoration site selection; and (vi) cost-benefit analyses of restoration for coastal hazard risk reduction. Summaries of current local or regional-scale studies, including modeling exercises are encouraged, especially if they evaluate social and economic impacts of different restoration options.

Ilsa B. Kuffner ¹, Joanie A. Kleypas², Les Kaufman³, Lisa J. Rodrigues⁴, Iliana Baums ⁵, John Parkinson⁶, Sarah Davies³, Sheila Kitchen ⁵, Margaret Miller ^7
1 U.S. Geological Survey (St. Petersburg, FL, USA)
² National Center for Atmospheric Research (Boulder, CO, USA)
³ Boston University (Boston, MA, USA)
⁴ Villanova University (Villanova, PA, USA)
⁵ Pennsylvania State University (State College, PA, USA)
⁶ University of South Florida (Tampa, FL, USA)
⁷ SECORE International (Hillard, OH, USA)

New combined abstract:

Coral populations have suffered dramatic declines due to increasing seawater temperatures and other stressors over the past four decades. However, coral reef ecosystems still exist across a wide range of biophysical settings, offering hope that adequate heterogeneity in coral populations exists upon which natural selection can act to allow species to persist. Further hope lies in the idea that humans can assist through active interventions and restoration measures based on ecological and evolutionary principles. From an evolutionary ecology perspective, the goal of coral restoration efforts is to establish self-sustaining, sexually reproducing populations that have sufficient genetic and phenotypic variation to adapt to changing environments. Corals pose unique challenges and advantages when designing effective restoration measures due to their life history that includes asexual and sexual reproduction as well as symbioses with microalgae and prokaryotes. The nature of coral reef ecosystems also provides unique opportunities for restoration design because reef environments are so variable in water-temperature regime, water clarity, level of nutrients and pollutants, wave energy, exposure to major storms, proximity to land effects, and exposure to human settlements. For this session, we invite talks that inform on how we might leverage naturally occurring genetic and phenotypic variability and environmental gradients to increase the likelihood of restoration success. We anticipate talks that address the development of new tools including biomarkers and large-scale genotyping platforms, those that quantify phenotypes such as coral growth metrics, colony morphology, symbiont and microbiome assemblages, and those that answer questions about the scale and speed of adaptation to changing conditions. Studies that link genetic characterization with phenotypic expression, that explore inbreeding and outbreeding depression, hybridization, gene flow, and interactions with symbionts and other species in the community are also welcomed. The ability to harness holobiont plasticity and stress response in a heterogeneous environment is at the core of creating "coral reefs in waiting," i.e., the collection of pieces required for natural reef reassembly and persistence into the Anthropocene.

Edwin A. Hernández-Delgado¹, Samuel E. Suleimán-Ramos¹, Elisa Bayraktarov², Phanor Montoya-Maya^3
1 Sociedad Ambiente Marino (San Juan, Puerto Rico)
² The University of Queensland (Brisbane, Australia)
³ Corales de Paz (Santiago de Cali, Colombia)

Coral reefs worldwide are degrading rapidly due to climate change, overfishing, pollution and coastal development. In areas where natural recovery is negligible or where conservation is not enough, restoration – or the process of assisting the recovery of a disturbed ecosystem, may become critical. The Reef Futures 2018 conference brought together a large international community of reef restoration experts, businesses, and civil organizations and galvanized them to joint efforts to save coral reefs through restoration. During the conference we found that, in contrast to other coral reef areas in the world, learnings from long-term and ongoing coral reef restoration projects done by scientists and practitioners especially in the Spanish-speaking parts of the Caribbean and Eastern Tropical Pacific were poorly shared with the international scientific community. This session aims to showcase major coral reef restoration projects from the Caribbean and Eastern Tropical Pacific and invite for collaboration and knowledge transfer between coral reef restoration projects elsewhere in the world. We will specifically focus on the motivations for these restoration efforts, their total project cost, spatial extent, and recent advances. Restoration interventions using different techniques will be presented and their successes (or failures) evaluated. This is the first ICRS symposium focused at overcoming the language barriers between Spanish and English for coral reef restoration. It aims to connect international researchers, practitioners and resource managers on the mission of restoring global coral reefs.

Tom Moore¹, Tali Vardi¹, Petra Lundgren^2
1 NOAA Restoration Center (St. Petersburg, FL, USA)
² Great Barrier Reef Foundation (Brisbane, Australia)

Saving the world's coral reefs will require a multi-pronged approach that ranges from actions at the local to the global level. Globally we need to dramatically and rapidly reduce energy consumption, switch to renewable sources of energy, and conserve carbon-absorbing ecosystems (forests, wetlands, and mangroves). Locally we need to manage threats such as overfishing and pollution, while at the same time repopulating target reefs with resilient, genetically diverse and reproductively viable populations through restoration and novel ecological interventions. Immediate and aggressive action to address these threats, while critical, is only part of the larger equation to ensuring a future for coral reefs and the ecological and economic services they provide. Carbon already released into the atmosphere will continue to warm ocean waters to a level inhospitable to corals for decades to come. Increased bleaching combined with reproductive failures and continually decreasing population size sets the stage for complete ecological collapse. If the critical ecologic and economic functions that corals reefs provide the world today are to be preserved, it is necessary to buy time and increase ecosystem resilience in the shorter term. Coral reef restoration can help span the predicted gap between the present when existing coral populations are threatened with extinction, and a future ocean that is hospitable again to corals. Current work is showing that restoration of reefs is possible, and the spatial scale of success is steadily increasing. In the near future, by harnessing promising research on novel ecological and genetic intervention strategies, restored reefs may be more resilient than their natural counterparts. Working to close the gap between success at the local level and impact at the ecosystem level will not be easy or quick, but in the face of a rapidly declining population is necessary to maintain the ecosystem services that coral reefs provide.

Peter Harrison ¹, Dirk Petersen ^2
1 Southern Cross University (Lismore, Australia)
² SECORE International, Inc. (Bremen, Germany)

Coral communities and the reef systems they engineer are declining significantly in most reef regions globally. Loss of corals on many reefs is now so profound that natural coral population recovery via sexual reproduction and recruitment is compromised, leading to ongoing declines in coral community and reef health. Various coral restoration techniques have been used in recent decades to initiate coral populations on small areas of reef but ecologically meaningful reef restoration requires much larger-scale and more cost-effective solutions. This session will focus on recent advances and innovations in coral sexual propagation and scalable multidisciplinary solutions required for successful larger-scale coral restoration and recovery of resilient reef ecosystems.

Sarah Frias-Torres ¹, Tom Moore^2
1 Vulcan Inc. (Seattle, WA, USA)
² NOAA Restoration Center (St. Petersburg, FL, USA)

As coral reefs continue to decline worldwide, combining traditional conservation with active restoration is essential to support resilience in these threatened ecosystems. This session will focus both on success stories and strategies for upscaling restoration: to mass-produce bleaching-resistant reef building corals for transplantation onto degraded reefs at the scale of hectares rather than square meters. All methods of mass coral production (Propagation of sexual recruits, asexual propagation by fragmentation and microfragmenting) and transplantation will be considered, including the use of new technologies and automation. Specifically we expect presentations quantifying restoration success including: before-after-control studies of restoration impacts on benthic and fish communities, coral genomics, restoration to dissipate high energy in coastal environments, demographic monitoring in site selection, development of self sustaining thickets, engagement and participation of marginalized base communities, and case studies linking managers priorities with restoration and vice versa.

Madeleine van Oppen ¹, Sarah Frias-Torres², Manuel Aranda³, James Guest^4
1 The University of Melbourne (Parkville, Australia)
² Vulcan Inc. (Seattle, WA, USA)
³ KAUST (Thuwal, Saudi Arabia)
⁴ Newcastle University (Newcastle, UK)

Coral reefs are home to about a quarter of all marine species, and their economic value far exceeds that of any other ecosystem in the world, including estuaries, tropical rain forests and wetlands. Alarmingly, coral reefs are in rapid decline due to a multitude of anthropogenic activities causing mechanical damage, deteriorating water quality, and ocean acidification and warming. Climate models based on unmitigated greenhouse gas emissions predict heat-induced mass bleaching will occur on most coral reefs every summer within this century, and even under the best-case CO₂ emission scenarios oceans will continue to warm and corals will decline further. Corals are capable of adaptation and acclimatisation and resilient reefs may recover unaided, however, natural rates of adaptation and recovery may not be sufficient to keep up with the current rate of global change. To increase the likelihood of coral reef persistence within this century, human interventions that increase coral climate resilience are thus urgently required; not as replacements for conventional management and reductions in greenhouse gas emissions, but as additional interventions integrated with these actions. This half-day session will present developments and findings in the emerging field of assisted evolution (AE). AE includes a variety of bioengineering methods targeted at the coral host animal or any of its associated microbial symbionts, such as assisted gene flow, selective breeding, directed evolution of microbial symbionts, and probiotics. Genetic engineering and synthetic biology approaches are now also beginning to be considered. The half-day session of talks will be followed by a lunch-time panel Q&A discussion. The session will be dedicated to the late Ruth Gates, who was one of the pioneers of AE in corals.

Carin Jantzen¹, Christian Wild², Michelle Calvert ^3
1 SECORE International (Hilliard, OH, USA)
² University of Bremen (Bremen, Germany)
³ Horniman Museum and Gardens (London, UK)

This open session presents all contributions related to Theme 14.

Arjun Chennu ¹, Emma Kennedy ², James Robinson ^3
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² University of Queensland (Brisbane, Australia)
3 Lancaster University (Lancaster, UK)

This open session presents all contributions related to Theme 15, which are not covered by the below specialised sessions.

James Robinson ¹, Alice Rogers², Kirsty Nash³, Shaun Wilson^4
1 Lancaster University (Lancaster, UK)
² Victoria University of Wellington (Wellington, New Zealand)
³ Institute for Marine and Antarctic Studies (Hobart, Australia)
⁴ Department of Biodiversity, Conservation and Attractions (Australia)

Coral reef fisheries are a conduit for many valuable ecosystem goods and services. For people, seafood products are of high nutritional value and an important source of income to many coastal communities. For reef ecosystems, fishing can influence ecosystem functioning through selective removal of species and individuals, often flattening biomass pyramids and reducing biodiversity. Yet as marine heatwaves cause declines in coral habitat and tropical fishes migrate polewards in response to long-term ocean warming, climate impacts are also altering the structure and function of fish assemblages to produce new and unexpected ecological configurations. In response, coral reef fishers are exploiting increases in herbivore productivity after coral bleaching events, while the tropicalization of fish communities is altering catch compositions at regional scales. Future tropical fisheries will thus be constrained by ecological responses to climate change (e.g. how species compositions change), and be shaped by how coastal communities interact with altered ecosystems. Examples from Kenya suggest that ecosystem protection through gear regulation can compensate for climate impacts while, for Pacific islands, gear diversification may help fishers to target climate change 'winners', such as pelagic fishes. For food security, trade networks could be harnessed to ensure that climate-impacted regions can access seafood, but this will require an improved understanding of the nutritional implications of climate changes.

Hauke Reuter ¹, Jaap Kaandorp^2
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² University of Amsterdam (Amsterdam, The Netherlands)

Coral reefs rely on the fragile balance of processes that interact between various components on different spatio-temporal scales and allow the establishment of healthy coral reef ecosystems. Mathematical simulation models are increasingly important tools to summarize our current understanding of the processes affecting the resilience and vulnerability of coral reef ecosystems to anthropogenic and natural disturbances. The integration of knowledge from different disciplines into mathematical models facilitates the identification of regionally important drivers and contributes to science-based management, and also allows identifying knowledge gaps for future research. The proposed session welcomes all contributions that highlight the added value of model applications to advance our understanding of coral reef ecosystems and their potential response to future environmental change. Such approaches include statistical modeling and data analysis, dynamic modeling of biogeochemical, ecological, and physiological processes that affect reef status, as well as models for management that interlink ecological and human domains. In order to develop informed coral reef management strategies, we need an overarching understanding of reef related processes utilizing newly established data bases, and integrating interdisciplinary knowledge in numerical simulations. In this session we want to bring together scientists from different approaches to summarize the huge innovative potential of simulation models for reef research and to discuss the uncertain future of coral reefs. We also welcome contributions that aim to use this knowledge to develop coral reef management strategies to help coral reefs cope with anthropogenic and natural disturbances.

Marleen Stuhr¹, Christiane Schmidt², Martina de Freitas Prazeres ^3
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² University of Angers (Angers, France)
³ Naturalis Biodiversity Center (Leiden, The Netherlands)

Anthropogenic impacts are transforming coral reefs at an unprecedented rate, changing species diversity and composition, and ultimately altering ecosystem services. Photosymbiont-bearing large benthic foraminifera (LBF) are crucial carbonate producers in reefs, and modify the benthic environment through the production of calcium carbonate. As with reef-building corals, they rely on symbiosis with algae to prosper in shallow tropical seas. Throughout the Cenozoic hothouse climate LBF dominated shallow carbonate platforms, during which the concentration of atmospheric CO₂ and seawater temperatures significantly exceeded current values. Modern LBF are ideally suited as bioindicators of water quality due to their sensitivity to environmental changes. LBF are also often used as model systems for studying (photo)symbiosis due to their short generational times (weeks to months). In addition, LBF are easily maintained in aquarium systems, and their small physical size avoids many logistical problems with other model organisms. Recent experimental studies and reports from extreme reef habitats have shown that some LBF are resistant to temporal or regional variations in environmental conditions, and are able to quickly respond to such changes. This may be due to the presence of a high diversity in algal symbiont types and the flexibility/specificity of algae and bacteria present in their microbiome. Finally, molecular approaches unveiled cryptic diversity and mechanisms of cellular acclimatization. We invite contributions on the latest research on LBF. Specially, we encourage submissions addressing: the application of LBF in coral reef assessments, the use of LBF in microbiome studies, LBF as model organisms for photosymbiosis, the consequences of LBF range expansions and studies on their general response to varying environmental stressors. This session aims to increase our understanding of the biodiversity and ecological importance of LBF in future reef environments.

Thomas Mann¹, Paul Kench^2
1 Leibniz Centre for Tropical Marine Research (Bremen, Germany)
² Simon Fraser University (Burnaby, Canada)

Coral reef islands represent the product of interactions between ecological and physical processes on coral reef platforms. Due to their low-lying nature and the intricate connections between sea level, reef growth, reef ecology and wave processes, coral reef islands are likely facing a transitional phase resulting from climate change and future sea-level rise. However, the morphological response of reef islands to these changing boundary conditions is still poorly resolved. Such transformation in island and reef-fringed coastlines is of critical concern to coastal communities. A major challenge for reef island science is to improve projections of how islands will respond to climatic change and associated sea-level rise over the 21st century. Addressing this gap in reef island science requires improved knowledge of; (i) the intimate linkages between reef ecology and processes that modulate sediment supply to islands; (ii) the nearshore hydrodynamics that force island physical change and (iii) understanding of the morphodynamics of islands. This session invites contributions that span and/or integrate these complementary fields of expertise with a focus on islands and island change. We aim to bring together experts from the fields of reef geology, geomorphology, paleontology, biology, ecology, remote sensing and wave and climate modeling in order to determine the state of the art and discuss future research directions.

William Skirving ¹, Mark Eakin², Ove Hoegh-Guldberg³, Simon Donner⁴, Neal Cantin^5
1 NOAA (Cranbrook, Australia)
² NOAA (College Park, MD, USA)
³ University of Qeensland (Brisbane, Australia)
⁴ University of British Columbia (Vancouver, Canada)
⁵ Australian Institute of Marine Science (Cape Cleveland, Australia)

1998 is recognised as being the first global mass bleaching event. It was subsequently followed by global events in 2010, 2015, 2016 and 2017 with the last three a single event that began in 2014 and continued into 2017. The 2014-17 global coral bleaching event was the longest, most extensive, most intense (in terms of accumulated heat stress), and probably most damaging (in terms of coral mortality) ever recorded. The event coincided with three consecutive record-setting years for globally averaged surface temperature: 2014 set a record that was surpassed in 2015, which in turn was surpassed in 2016; global temperature during 2017 became the third-highest on record. Anomalously warm ocean temperature patterns through this period were associated with the El Niño-Southern Oscillation, and oceanographic phenomena, such as "the blob". Mass coral bleaching has been long-associated with temperature above expected summertime conditions. Many coral reef areas experienced their worst observed bleaching and more than half bleached twice or more during the 36-month period. While the 2014/17 global mass bleaching event was the first multi-year bleaching event, was this event a precursor of things to come? A more complete understanding of this and previous mass coral bleaching events is needed. Towards this goal, it is helpful to examine global and regional heat stress and subsequent mass coral bleaching through time, including past, present, and future. To achieve this analyses requires the use of all available tools and data. To date, satellite products such as those developed by NOAA Coral Reef Watch have dominated global and long-term analyses, however other data sets are as valuable or even more valuable. For example, bleaching data from coral cores and from in situ surveys are essential. While satellite heat stress products record what the corals should experience, we must also know what they did experience. Understanding future coral bleaching requires a good understanding of what has happened in the past and what might happen in the future. Climate models are therefore an invaluable inclusion to this suite of tools as we seek to understand the fate of corals in a warming world. This session seeks papers and posters that utilize any and all data to improve our understanding of mass coral bleaching in time and space. It also wishes to include new and improved methodologies and tools for shedding light on our understanding of mass coral bleaching in the past, present, and future.

Malin Pinsky¹, Madhavi Colton^2
1 Rutgers University (New Brunswick, NJ, USA)
² Coral Reef Alliance (Oakland, CA, USA) 

Coral reefs are already experiencing the effects of climate change and projections from recent bleaching suggest widespread decline of existing reefs. On the other hand, reef-building corals have successfully coped with environmental change over their evolutionary history. Can evolution also help corals cope with rapid rates of current and future environmental change? While some models suggest that it can’t, others offer hope. This session seeks contributions from ecology, evolutionary biology, physiology, genomics, geology, and conservation biology to understand the potential for evolutionary rescue in corals. Evolutionary rescue occurs when advantageous genetic adaptation saves a population that would otherwise go extinct due to a drastic environmental change. Possible talk topics include the influences of population size, demographic connectivity, and diversity (e.g., genomic, phenotypic, symbiont, and species) on evolutionary rescue; deep time perspectives on coral evolution and environmental change; physiological mechanisms for evolution of higher thermal tolerance; genomic responses to bleaching; or conservation mechanisms to facilitate evolutionary rescue. This session seeks to include case studies of coral adaptation or recovery, eco-evolutionary modeling projects, and mechanistic research, and contributions that describe management actions that facilitate evolutionary rescue at different spatial scales.