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Foulk A, Gouhier T, Choi F, Torossian JL, Matzelle A, Sittenfeld D, Helmuth B. Physiologically informed organismal climatologies reveal unexpected spatiotemporal trends in temperature. CONSERVATION PHYSIOLOGY 2024; 12:coae025. [PMID: 38779431 PMCID: PMC11109819 DOI: 10.1093/conphys/coae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/15/2024] [Accepted: 04/15/2024] [Indexed: 05/25/2024]
Abstract
Body temperature is universally recognized as a dominant driver of biological performance. Although the critical distinction between the temperature of an organism and its surrounding habitat has long been recognized, it remains common practice to assume that trends in air temperature-collected via remote sensing or weather stations-are diagnostic of trends in animal temperature and thus of spatiotemporal patterns of physiological stress and mortality risk. Here, by analysing long-term trends recorded by biomimetic temperature sensors designed to emulate intertidal mussel temperature across the US Pacific Coast, we show that trends in maximal organismal temperature ('organismal climatologies') during aerial exposure can differ substantially from those exhibited by co-located environmental data products. Specifically, using linear regression to compare maximal organismal and environmental (air temperature) climatologies, we show that not only are the magnitudes of body and air temperature markedly different, as expected, but so are their temporal trends at both local and biogeographic scales, with some sites showing significant decadal-scale increases in organismal temperature despite reductions in air temperature, or vice versa. The idiosyncratic relationship between the spatiotemporal patterns of organismal and air temperatures suggests that environmental climatology cannot be statistically corrected to serve as an accurate proxy for organismal climatology. Finally, using quantile regression, we show that spatiotemporal trends vary across the distribution of organismal temperature, with extremes shifting in different directions and at different rates than average metrics. Overall, our results highlight the importance of quantifying changes in the entire distribution of temperature to better predict biological performance and dispel the notion that raw or 'corrected' environmental (and specially air temperature) climatologies can be used to predict organismal temperature trends. Hence, despite their widespread coverage and availability, the severe limitations of environmental climatologies suggest that their role in conservation and management policy should be carefully considered.
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Affiliation(s)
- Aubrey Foulk
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
| | - Tarik Gouhier
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
| | - Francis Choi
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
| | - Jessica L Torossian
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
- Volpe Center, U.S. Department of Transportation, Cambridge, MA 02142, USA
| | - Allison Matzelle
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
| | - David Sittenfeld
- Center for the Environment, Museum of Science, Boston, MA 02114, USA
- School of Public Policy and Urban Affairs, Northeastern University, Boston, MA 02115, USA
| | - Brian Helmuth
- Department of Marine and Environmental Sciences, Northeastern University Marine Science Center, Nahant, MA 01908, USA
- School of Public Policy and Urban Affairs, Northeastern University, Boston, MA 02115, USA
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2
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Klein SG, Roch C, Duarte CM. Systematic review of the uncertainty of coral reef futures under climate change. Nat Commun 2024; 15:2224. [PMID: 38472196 DOI: 10.1038/s41467-024-46255-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
Climate change impact syntheses, such as those by the Intergovernmental Panel on Climate Change, consistently assert that limiting global warming to 1.5 °C is unlikely to safeguard most of the world's coral reefs. This prognosis is primarily based on a small subset of available models that apply similar 'excess heat' threshold methodologies. Our systematic review of 79 articles projecting coral reef responses to climate change revealed five main methods. 'Excess heat' models constituted one third (32%) of all studies but attracted a disproportionate share (68%) of citations in the field. Most methods relied on deterministic cause-and-effect rules rather than probabilistic relationships, impeding the field's ability to estimate uncertainty. To synthesize the available projections, we aimed to identify models with comparable outputs. However, divergent choices in model outputs and scenarios limited the analysis to a fraction of available studies. We found substantial discrepancies in the projected impacts, indicating that the subset of articles serving as a basis for climate change syntheses may project more severe consequences than other studies and methodologies. Drawing on insights from other fields, we propose methods to incorporate uncertainty into deterministic modeling approaches and propose a multi-model ensemble approach to generating probabilistic projections for coral reef futures.
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Affiliation(s)
- Shannon G Klein
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
| | - Cassandra Roch
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Carlos M Duarte
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
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3
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Klepac CN, Petrik CG, Karabelas E, Owens J, Hall ER, Muller EM. Assessing acute thermal assays as a rapid screening tool for coral restoration. Sci Rep 2024; 14:1898. [PMID: 38253660 PMCID: PMC10803358 DOI: 10.1038/s41598-024-51944-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Escalating environmental threats to coral reefs coincides with global advancements in coral restoration programs. To improve long-term efficacy, practitioners must consider incorporating genotypes resilient to ocean warming and disease while maintaining genetic diversity. Identifying such genotypes typically occurs under long-term exposures that mimic natural stressors, but these experiments can be time-consuming, costly, and introduce tank effects, hindering scalability for hundreds of nursery genotypes used for outplanting. Here, we evaluated the efficacy of the acute Coral Bleaching Automated Stress System (CBASS) against long-term exposures on the bleaching response of Acropora cervicornis, the dominant restoration species in Florida's Coral Reef. Comparing bleaching metrics, Fv/Fm, chlorophyll, and host protein, we observed similar responses between the long-term heat and the CBASS treatment of 34.3 °C, which was also the calculated bleaching threshold. This suggests the potential of CBASS as a rapid screening tool, with 90% of restoration genotypes exhibiting similar bleaching tolerances. However, variations in acute bleaching phenotypes arose from measurement timing and experiment heat accumulation, cautioning against generalizations solely based on metrics like Fv/Fm. These findings identify the need to better refine the tools necessary to quickly and effectively screen coral restoration genotypes and determine their relative tolerance for restoration interventions.
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Affiliation(s)
- C N Klepac
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA.
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA.
| | - C G Petrik
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA
- National Coral Reef Institute, Nova Southeastern University, Dania Beach, FL, USA
| | - E Karabelas
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - J Owens
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA
- Tufts University, Worcester, MA, USA
| | - E R Hall
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA
- Mote Marine Laboratory, Sarasota, FL, USA
| | - E M Muller
- Mote Marine Laboratory, International Center for Coral Reef Research and Restoration, Summerland Key, FL, USA
- Mote Marine Laboratory, Sarasota, FL, USA
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4
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Lachs L, Donner SD, Mumby PJ, Bythell JC, Humanes A, East HK, Guest JR. Emergent increase in coral thermal tolerance reduces mass bleaching under climate change. Nat Commun 2023; 14:4939. [PMID: 37607913 PMCID: PMC10444816 DOI: 10.1038/s41467-023-40601-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023] Open
Abstract
Recurrent mass bleaching events threaten the future of coral reefs. To persist under climate change, corals will need to endure progressively more intense and frequent marine heatwaves, yet it remains unknown whether their thermal tolerance can keep pace with warming. Here, we reveal an emergent increase in the thermal tolerance of coral assemblages at a rate of 0.1 °C/decade for a remote Pacific coral reef system. This led to less severe bleaching impacts than would have been predicted otherwise, indicating adaptation, acclimatisation or shifts in community structure. Using future climate projections, we show that if thermal tolerance continues to rise over the coming century at the most-likely historic rate, substantial reductions in bleaching trajectories are possible. High-frequency bleaching can be fully mitigated at some reefs under low-to-middle emissions scenarios, yet can only be delayed under high emissions scenarios. Collectively, our results indicate a potential ecological resilience to climate change, but still highlight the need for reducing carbon emissions in line with Paris Agreement commitments to preserve coral reefs.
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Affiliation(s)
- Liam Lachs
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK.
- Institute of Resources, Environment and Sustainability, and Department of Geography, University of British Columbia, Vancouver, BC, Canada.
| | - Simon D Donner
- Institute of Resources, Environment and Sustainability, and Department of Geography, University of British Columbia, Vancouver, BC, Canada
| | - Peter J Mumby
- Marine Spatial Ecology Lab, School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
- Palau International Coral Reef Center, Koror, Palau
| | - John C Bythell
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Adriana Humanes
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Holly K East
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - James R Guest
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
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5
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Bay LK, Gilmour J, Muir B, Hardisty PE. Management approaches to conserve Australia's marine ecosystem under climate change. Science 2023; 381:631-636. [PMID: 37561873 DOI: 10.1126/science.adi3023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/23/2023] [Indexed: 08/12/2023]
Abstract
Australia's coastal marine ecosystems have a deep cultural significance to Indigenous Australians, include multiple World Heritage sites, and support the nation's rapidly growing blue economy. Yet, increasing local pressures and global climate change are expected to undermine the biological, social, cultural, and economic value of these ecosystems within a human generation. Mitigating the causes of climate change is the most urgent action to secure their future; however, conventional and new management actions will play roles in preserving ecosystem function and value until that is achieved. This includes strategies codeveloped with Indigenous Australians that are guided by traditional ecological knowledge and a modeling and decision support framework. We provide examples of developments at one of Australia's most iconic ecosystems, the Great Barrier Reef, where recent, large block funding supports research, governance, and engagement to accelerate the development of tools for management under climate change.
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Affiliation(s)
- Line K Bay
- Australian Institute of Marine Science, Townsville, QLD, Australia
| | - James Gilmour
- Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Bob Muir
- Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Paul E Hardisty
- Australian Institute of Marine Science, Townsville, QLD, Australia
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6
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Richards TJ, McGuigan K, Aguirre JD, Humanes A, Bozec YM, Mumby PJ, Riginos C. Moving beyond heritability in the search for coral adaptive potential. GLOBAL CHANGE BIOLOGY 2023; 29:3869-3882. [PMID: 37310164 DOI: 10.1111/gcb.16719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 06/14/2023]
Abstract
Global environmental change is happening at unprecedented rates. Coral reefs are among the ecosystems most threatened by global change. For wild populations to persist, they must adapt. Knowledge shortfalls about corals' complex ecological and evolutionary dynamics, however, stymie predictions about potential adaptation to future conditions. Here, we review adaptation through the lens of quantitative genetics. We argue that coral adaptation studies can benefit greatly from "wild" quantitative genetic methods, where traits are studied in wild populations undergoing natural selection, genomic relationship matrices can replace breeding experiments, and analyses can be extended to examine genetic constraints among traits. In addition, individuals with advantageous genotypes for anticipated future conditions can be identified. Finally, genomic genotyping supports simultaneous consideration of how genetic diversity is arrayed across geographic and environmental distances, providing greater context for predictions of phenotypic evolution at a metapopulation scale.
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Affiliation(s)
- Thomas J Richards
- School of Biological Sciences, The University of Queensland, Queensland, St Lucia, Australia
| | - Katrina McGuigan
- School of Biological Sciences, The University of Queensland, Queensland, St Lucia, Australia
| | - J David Aguirre
- School of Natural Sciences, Massey University, Auckland, New Zealand
| | - Adriana Humanes
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Yves-Marie Bozec
- School of Biological Sciences, The University of Queensland, Queensland, St Lucia, Australia
| | - Peter J Mumby
- School of Biological Sciences, The University of Queensland, Queensland, St Lucia, Australia
| | - Cynthia Riginos
- School of Biological Sciences, The University of Queensland, Queensland, St Lucia, Australia
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7
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Cornwall CE, Comeau S, Donner SD, Perry C, Dunne J, van Hooidonk R, Ryan JS, Logan CA. Coral adaptive capacity insufficient to halt global transition of coral reefs into net erosion under climate change. GLOBAL CHANGE BIOLOGY 2023; 29:3010-3018. [PMID: 36943744 DOI: 10.1111/gcb.16647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/04/2023] [Accepted: 02/07/2023] [Indexed: 05/03/2023]
Abstract
Projecting the effects of climate change on net reef calcium carbonate production is critical to understanding the future impacts on ecosystem function, but prior estimates have not included corals' natural adaptive capacity to such change. Here we estimate how the ability of symbionts to evolve tolerance to heat stress, or for coral hosts to shuffle to favourable symbionts, and their combination, may influence responses to the combined impacts of ocean warming and acidification under three representative concentration pathway (RCP) emissions scenarios (RCP2.6, RCP4.5 and RCP8.5). We show that symbiont evolution and shuffling, both individually and when combined, favours persistent positive net reef calcium carbonate production. However, our projections of future net calcium carbonate production (NCCP) under climate change vary both spatially and by RCP. For example, 19%-35% of modelled coral reefs are still projected to have net positive NCCP by 2050 if symbionts can evolve increased thermal tolerance, depending on the RCP. Without symbiont adaptive capacity, the number of coral reefs with positive NCCP drops to 9%-13% by 2050. Accounting for both symbiont evolution and shuffling, we project median positive NCPP of coral reefs will still occur under low greenhouse emissions (RCP2.6) in the Indian Ocean, and even under moderate emissions (RCP4.5) in the Pacific Ocean. However, adaptive capacity will be insufficient to halt the transition of coral reefs globally into erosion by 2050 under severe emissions scenarios (RCP8.5).
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Affiliation(s)
- Christopher Edward Cornwall
- School of Biological Sciences and Coastal People Southern Skies, Victoria University of Wellington, Wellington, New Zealand
| | - Steeve Comeau
- Laboratoire d'Océanographie de Villefranche, CNRS-INSU, Sorbonne Université, Villefranche-sur-Mer, France
| | - Simon D Donner
- Institute of Resources, Environment and Sustainability / Department of Geography, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris Perry
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - John Dunne
- NOAA/OAR Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA
| | - Ruben van Hooidonk
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric and Earth Science, University of Miami, Miami, Florida, USA
- Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, Florida, USA
| | - James S Ryan
- Department of Marine Science, California State University, Monterey Bay, California, USA
| | - Cheryl A Logan
- Department of Marine Science, California State University, Monterey Bay, California, USA
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8
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Lachs L, Humanes A, Pygas DR, Bythell JC, Mumby PJ, Ferrari R, Figueira WF, Beauchamp E, East HK, Edwards AJ, Golbuu Y, Martinez HM, Sommer B, van der Steeg E, Guest JR. No apparent trade-offs associated with heat tolerance in a reef-building coral. Commun Biol 2023; 6:400. [PMID: 37046074 PMCID: PMC10097654 DOI: 10.1038/s42003-023-04758-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/24/2023] [Indexed: 04/14/2023] Open
Abstract
As marine species adapt to climate change, their heat tolerance will likely be under strong selection. Yet trade-offs between heat tolerance and other life history traits could compromise natural adaptation or assisted evolution. This is particularly important for ecosystem engineers, such as reef-building corals, which support biodiversity yet are vulnerable to heatwave-induced mass bleaching and mortality. Here, we exposed 70 colonies of the reef-building coral Acropora digitifera to a long-term marine heatwave emulation experiment. We tested for trade-offs between heat tolerance and three traits measured from the colonies in situ - colony growth, fecundity, and symbiont community composition. Despite observing remarkable within-population variability in heat tolerance, all colonies were dominated by Cladocopium C40 symbionts. We found no evidence for trade-offs between heat tolerance and fecundity or growth. Contrary to expectations, positive associations emerged with growth, such that faster-growing colonies tended to bleach and die at higher levels of heat stress. Collectively, our results suggest that these corals exist on an energetic continuum where some high-performing individuals excel across multiple traits. Within populations, trade-offs between heat tolerance and growth or fecundity may not be major barriers to natural adaptation or the success of assisted evolution interventions.
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Affiliation(s)
- Liam Lachs
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
| | - Adriana Humanes
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Daniel R Pygas
- Australian Institute of Marine Sciences, Townsville, QLD, 4810, Australia
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - John C Bythell
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Peter J Mumby
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD, 4072, Australia
- Palau International Coral Reef Center, Koror, 96940, Palau
| | - Renata Ferrari
- Australian Institute of Marine Sciences, Townsville, QLD, 4810, Australia
| | - Will F Figueira
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Elizabeth Beauchamp
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Holly K East
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Alasdair J Edwards
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Yimnang Golbuu
- Palau International Coral Reef Center, Koror, 96940, Palau
| | - Helios M Martinez
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Brigitte Sommer
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Eveline van der Steeg
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - James R Guest
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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9
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Walker NS, Nestor V, Golbuu Y, Palumbi SR. Coral bleaching resistance variation is linked to differential mortality and skeletal growth during recovery. Evol Appl 2023; 16:504-517. [PMID: 36793702 PMCID: PMC9923480 DOI: 10.1111/eva.13500] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 09/19/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
The prevalence of global coral bleaching has focused much attention on the possibility of interventions to increase heat resistance. However, if high heat resistance is linked to fitness tradeoffs that may disadvantage corals in other areas, then a more holistic view of heat resilience may be beneficial. In particular, overall resilience of a species to heat stress is likely to be the product of both resistance to heat and recovery from heat stress. Here, we investigate heat resistance and recovery among individual Acropora hyacinthus colonies in Palau. We divided corals into low, moderate, and high heat resistance categories based on the number of days (4-9) needed to reach significant pigmentation loss due to experimental heat stress. Afterward, we deployed corals back onto a reef in a common garden 6-month recovery experiment that monitored chlorophyll a, mortality, and skeletal growth. Heat resistance was negatively correlated with mortality during early recovery (0-1 month) but not late recovery (4-6 months), and chlorophyll a concentration recovered in heat-stressed corals by 1-month postbleaching. However, moderate-resistance corals had significantly greater skeletal growth than high-resistance corals by 4 months of recovery. High- and low-resistance corals on average did not exhibit skeletal growth within the observed recovery period. These data suggest complex tradeoffs may exist between coral heat resistance and recovery and highlight the importance of incorporating multiple aspects of resilience into future reef management programs.
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Affiliation(s)
- Nia S Walker
- Department of Biology Hopkins Marine Station of Stanford University Pacific Grove California USA.,Hawai'i Institute of Marine Biology University of Hawai'i at Mānoa Kāne'ohe Hawaii USA
| | | | | | - Stephen R Palumbi
- Department of Biology Hopkins Marine Station of Stanford University Pacific Grove California USA
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10
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Marzonie MR, Bay LK, Bourne DG, Hoey AS, Matthews S, Nielsen JJV, Harrison HB. The effects of marine heatwaves on acute heat tolerance in corals. GLOBAL CHANGE BIOLOGY 2023; 29:404-416. [PMID: 36285622 PMCID: PMC10092175 DOI: 10.1111/gcb.16473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/16/2022] [Accepted: 09/16/2022] [Indexed: 05/19/2023]
Abstract
Scleractinian coral populations are increasingly exposed to conditions above their upper thermal limits due to marine heatwaves, contributing to global declines of coral reef ecosystem health. However, historic mass bleaching events indicate there is considerable inter- and intra-specific variation in thermal tolerance whereby species, individual coral colonies and populations show differential susceptibility to exposure to elevated temperatures. Despite this, we lack a clear understanding of how heat tolerance varies across large contemporary and historical environmental gradients, or the selective pressures that underpin this variation. Here we conducted standardised acute heat stress experiments to identify variation in heat tolerance among species and isolated reefs spanning a large environmental gradient across the Coral Sea Marine Park. We quantified the photochemical yield (Fv /Fm ) of coral samples in three coral species, Acropora cf humilis, Pocillopora meandrina, and Pocillopora verrucosa, following exposure to four temperature treatments (local ambient temperatures, and + 3°C, +6°C and + 9°C above local maximum monthly mean). We quantified the temperature at which Fv /Fm decreased by 50% (termed ED50) and used derived values to directly compare acute heat tolerance across reefs and species. The ED50 for Acropora was 0.4-0.7°C lower than either Pocillopora species, with a 0.3°C difference between the two Pocillopora species. We also recorded 0.9°C to 1.9°C phenotypic variation in heat tolerance among reefs within species, indicating spatial heterogeneity in heat tolerance across broad environmental gradients. Acute heat tolerance had a strong positive relationship to mild heatwave exposure over the past 35 years (since 1986) but was negatively related to recent severe heatwaves (2016-2020). Phenotypic variation associated with mild thermal history in local environments provides supportive evidence that marine heatwaves are selecting for tolerant individuals and populations; however, this adaptive potential may be compromised by the exposure to recent severe heatwaves.
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Affiliation(s)
- Magena R. Marzonie
- Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- AIMS@JCUTownsvilleQueenslandAustralia
| | - Line K. Bay
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- AIMS@JCUTownsvilleQueenslandAustralia
| | - David G. Bourne
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
| | - Andrew S. Hoey
- Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Samuel Matthews
- Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Josephine J. V. Nielsen
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- AIMS@JCUTownsvilleQueenslandAustralia
- College of Public Health, Medical and Veterinary SciencesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Hugo B. Harrison
- Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- AIMS@JCUTownsvilleQueenslandAustralia
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