Standardized short‐term acute heat stress assays resolve historical differences in coral thermotolerance across microhabitat reef sites

Global Change Biology, Год журнала: 2020, Номер 26(8), С. 4328 - 4343

Опубликована: Июнь 21, 2020

Abstract Coral bleaching is one of the main drivers reef degradation. Most corals bleach and suffer mortality at just 1–2°C above their maximum monthly mean temperatures, but some species genotypes resist or recover better than others. Here, we conducted a series 18‐hr short‐term acute heat stress assays side‐by‐side with 21‐day long‐term experiment to assess ability both approaches resolve coral thermotolerance differences reflective in situ temperature thresholds. Using suite physiological parameters (photosynthetic efficiency, whitening, chlorophyll , host protein, algal symbiont counts, type association), assessed susceptibility Stylophora pistillata colonies from windward/exposed leeward/protected sites nearshore central Red Sea, which had previously shown differential during natural event. Photosynthetic efficiency was most indicative expected higher thermal tolerance protected site, denoted by an increased retention dark‐adapted quantum yields temperatures. These were resolved using experimental setups, as corroborated positive linear relationship, not observed for other parameters. Notably, per‐colony (genotype) that may have been masked acclimation effects experiment. our newly developed portable system termed Bleaching Automated Stress System (CBASS), thus highlight potential mobile, standardized fine‐scale thermotolerance. Accordingly, such be suitable large‐scale determination complement existing identify resilient genotypes/reefs downstream examination prioritization conservation/restoration. Development framework consistent recommendations National Academy Sciences Reef Restoration Adaptation Program committees new intervention restoration strategies.

Язык: Английский

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Coral‐bleaching responses to climate change across biological scales

Global Change Biology, Год журнала: 2022, Номер 28(14), С. 4229 - 4250

Опубликована: Апрель 27, 2022

Abstract The global impacts of climate change are evident in every marine ecosystem. On coral reefs, mass bleaching and mortality have emerged as ubiquitous responses to ocean warming, yet one the greatest challenges this epiphenomenon is linking information across scientific disciplines spatial temporal scales. Here we review some seminal recent coral‐bleaching discoveries from an ecological, physiological, molecular perspective. We also evaluate which data processes can improve predictive models provide a conceptual framework that integrates measurements biological Taking integrative approach scales, using for example hierarchical estimate major coral‐reef processes, will not only rapidly advance science but necessary guide decision‐making conservation efforts. To conserve encourage implementing mesoscale sanctuaries (thousands km 2 ) transcend national boundaries. Such networks protected reefs reef connectivity, through larval dispersal transverse thermal environments, genotypic repositories may become essential units selection environmentally diverse locations. Together, multinational be best chance corals persist change, while humanity struggles reduce emissions greenhouse gases net zero.

Язык: Английский

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Triggers, cascades, and endpoints: connecting the dots of coral bleaching mechanisms

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Год журнала: 2024, Номер 99(3), С. 715 - 752

Опубликована: Янв. 12, 2024

ABSTRACT The intracellular coral–dinoflagellate symbiosis is the engine that underpins success of coral reefs, one most diverse ecosystems on planet. However, breakdown and loss microalgal symbiont (i.e. bleaching) due to environmental changes are resulting in rapid degradation reefs globally. There an urgent need understand cellular physiology bleaching at mechanistic level help develop solutions mitigate reef crisis. Here, unprecedented scope, we present novel models integrate putative mechanisms within a common framework according triggers (initiators bleaching, e.g. heat, cold, light stress, hypoxia, hyposalinity), cascades (cellular pathways, photoinhibition, unfolded protein response, nitric oxide), endpoints (mechanisms loss, apoptosis, necrosis, exocytosis/vomocytosis). supported by direct evidence from cnidarian systems, indirectly through comparative evolutionary analyses non‐cnidarian systems. With this approach, new have been established between initiated different triggers. In particular, provide insights into poorly understood connections highlight role mechanism i.e. ‘symbiolysosomal digestion’, which symbiophagy. This review also increases approachability for specialists non‐specialists mapping vast landscape atlas comprehensible detailed models. We then discuss major knowledge gaps how future research may improve understanding cascade pathways (endpoints).

Язык: Английский

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Increasing comparability among coral bleaching experiments

Ecological Applications, Год журнала: 2020, Номер 31(4)

Опубликована: Ноя. 22, 2020

Abstract Coral bleaching is the single largest global threat to coral reefs worldwide. Integrating diverse body of work on critical understanding and combating this problem. Yet investigating drivers, patterns, processes poses a major challenge. A recent review published experiments revealed wide range experimental variables used across studies. Such approaches enhances discovery, but without full transparency in analytical methods used, can also make comparisons among studies challenging. To increase comparability not stifle innovation, we propose common framework for that includes consideration provenance, conditions, husbandry. For example, reporting number genets collection site temperature offset(s) from maximum monthly mean (MMM) site, light flow, feeding regime will greatly facilitate Similarly, quantifying response endosymbiont (Symbiodiniaceae) holobiont phenotypes (i.e., color, chlorophyll, cell density, mortality, skeletal growth) could further cross‐study comparisons. While no experiment provide data necessary determine responses all corals current future ocean warming, linking through as outlined here, would help experiments, synthetic insights into causes underlying mechanisms bleaching, reveal unique genets, species, regions. collaborative fosters strengthen inform reef management conservation strategies mitigate

Язык: Английский

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Insights into coral bleaching under heat stress from analysis of gene expression in a sea anemone model system

Proceedings of the National Academy of Sciences, Год журнала: 2020, Номер 117(46), С. 28906 - 28917

Опубликована: Ноя. 9, 2020

Significance Coral reefs are biodiversity hotspots of great ecological, economic, and aesthetic importance. Their global decline under climate change other stresses makes it urgent to understand the molecular bases their responses stress, including “bleaching,” in which corals' photosynthetic algal symbionts lost, thus depriving host animals a crucial source energy metabolic building blocks. We sought clues mechanisms that cause (or protect against) bleaching by analyzing patterns gene expression sea anemone relative corals during exposure heat stress sufficient induce bleaching. The results challenge some current ideas about while also suggesting hypotheses identifying genes prime targets for future genetic analyses.

Язык: Английский

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Response of large benthic foraminifera to climate and local changes: Implications for future carbonate production

Sedimentology, Год журнала: 2021, Номер 69(1), С. 121 - 161

Опубликована: Фев. 27, 2021

Abstract Large benthic foraminifera are major carbonate components in tropical platforms, important producers, stratigraphic tools and powerful bioindicators (proxies) of environmental change. The application large coral reef environments has gained considerable momentum recent years. These modern ecological assessments often carried out by micropalaeontologists or ecologists with expertise the identification foraminifera. However, have been under‐represented favour macro reef‐builders, for example, corals calcareous algae. contribute about 5% to reef‐scale sediment production. Their substantial size abundance reflected their symbiotic association living algae inside tests. When foraminiferal holobiont (the combination between host microalgal photosymbiont) dies, remaining test renourishes supply, which maintains stabilizes shorelines low‐lying islands. Geological records reveal episodes (i.e. late Palaeocene early Eocene epochs) prolific production warmer oceans than today, absence corals. This begs deeper consideration how will respond under future climatic scenarios higher atmospheric carbon dioxide ( p CO 2 ) oceans. In addition, studies highlighting complex evolutionary associations hosts algal photosymbionts, as well associated habitats, suggest potential increased tolerance a wide range conditions. full where currently dwell is not well‐understood terms present production, impact stressors. evidence acclimatization, at least few species well‐studied foraminifera, intensifying climate change within degrading ecosystems, prelude host–symbiont resilience different regimes habitats today. review also highlights knowledge gaps current understanding calcium producers across shallow shelf slope changing ocean

Язык: Английский

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Remarkably high and consistent tolerance of a Red Sea coral to acute and chronic thermal stress exposures

Limnology and Oceanography, Год журнала: 2021, Номер 66(5), С. 1718 - 1729

Опубликована: Фев. 15, 2021

Abstract Global warming is resulting in unprecedented levels of coral mortality due to mass bleaching events and, more recently, marine heatwaves, where rapid increases seawater temperature cause within days. Here, we compare the response a ubiquitous scleractinian coral, Stylophora pistillata , from northern Red Sea acute (7 h) and chronic (7–11 d) thermal stress that include treatments 27°C (i.e., local maximum monthly mean), 29.5°C, 32°C, 34.5°C, assess recovery corals following exposure. Overall, S. exhibited remarkably similar responses stress, responding primarily treatment rather than duration or heating rate. Additionally, displayed an exceptionally high tolerance, maintaining their physiological performance suffering little no loss algal symbionts chlorophyll up before host suffered tissue necrosis at 34.5°C. While there was some variability metrics, photosynthetic efficiency measurements quantum yield Fv / Fm ) accurately reflected overall patterns, with these used produce effective dose (ED 50 metric as proxy for tolerance corals. This approach produced ED values experiments (34.47°C vs. 33.81°C), highlighting potential assays systematic standardized quantitively upper limits reef‐building using portable experimental system.

Язык: Английский

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Effects of sediment exposure on corals: a systematic review of experimental studies

Environmental Evidence, Год журнала: 2022, Номер 11(1)

Опубликована: Фев. 7, 2022

Management actions that address local-scale stressors on coral reefs can rapidly improve water quality and reef ecosystem condition. In response to managers who need actionable thresholds for coastal runoff dredging, we conducted a systematic review meta-analysis of experimental studies explore the effects sediment corals. We identified exposure levels 'adversely' affect corals while accounting bearing (deposited vs. suspended), life-history stage, species, thus providing empirically based estimates stressor vulnerable reefs.

Язык: Английский

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Empirically derived thermal thresholds of four coral species along the Red Sea using a portable and standardized experimental approach

Coral Reefs, Год журнала: 2022, Номер 41(2), С. 239 - 252

Опубликована: Март 22, 2022

Abstract Global warming is causing an unprecedented loss of species and habitats worldwide. This particularly apparent for tropical coral reefs, with increasing number reefs experiencing mass bleaching mortality on annual basis. As such, there a growing need standardized experimental approach to rapidly assess the thermal limits corals predict survival across regions. Using portable system, Coral Bleaching Automated Stress System (CBASS), we conducted 18 h acute stress assays quantitively determine upper four length Red Sea coastline, from Gulf Aqaba (GoA) Djibouti (~ 2100 km). We measured dark-acclimated photosynthetic efficiency ( F v /F m ), algal symbiont density, chlorophyll a, visual intensity following heat stress. was most precise response variable assessed, advancing effective dose 50 (ED50, i.e., temperature at which 50% initial measured) as empirically derived proxy tolerance. ED50 thresholds central/southern populations were consistently higher Acropora hemprichii, Pocillopora verrucosa, Stylophora pistillata (0.1–1.8 °C above GoA corals, respectively), in line prevailing warmer maximum monthly means (MMMs), though lower than relative site MMMs (1.5–3.0 °C). P. verrucosa had lowest overall. Despite coming hottest site, Porites lobata southern Sea, suggesting long-term physiological damage or ongoing recovery severe, prior event. Altogether, CBASS resolved historical, taxonomic, possibly recent environmental drivers variation thresholds, highlighting potential standardized, short-term assay universal assessing ecological evolutionary corals.

Язык: Английский

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Within-population variability in coral heat tolerance indicates climate adaptation potential

Proceedings of the Royal Society B Biological Sciences, Год журнала: 2022, Номер 289(1981)

Опубликована: Авг. 31, 2022

Coral reefs are facing unprecedented mass bleaching and mortality events due to marine heatwaves climate change. To avoid extirpation, corals must adapt. Individual variation in heat tolerance its heritability underpin the potential for coral adaptation. However, magnitude of variability within populations is largely unresolved. We address this knowledge gap by exposing from a single reef an experimental heatwave. found that double stress dosage was required induce most-tolerant 10%, compared least-tolerant 10% population. By end exposure, all were dead, whereas remained alive. contextualize scale result over coming century, we show under ambitious future emissions scenario, such differences thresholds equate up 17 years delay until onset annual conditions. limited only 10 high scenario. Our results substantial which suggests scope natural or assisted evolution limit impacts change short-term. For persist through adaptation keep pace with ocean warming, reductions be realized.

Язык: Английский

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