Coral bleaching patterns are the outcome of complex biological and environmental networking

Global Change Biology, Journal Year: 2019, Volume and Issue: 26(1), P. 68 - 79

Published: Oct. 16, 2019

Abstract Continued declines in coral reef health over the past three decades have been punctuated by severe mass bleaching‐induced mortality events that grown intensity and frequency under climate change. Intensive global research efforts therefore persistently focused on bleaching phenomena to understand where corals bleach, when why—resulting a large—yet still somewhat patchy—knowledge base. Particularly catastrophic 5 years catalyzed calls for more diverse set of management tools, extending far beyond mitigation protection, also include aggressive interventions. However, effectiveness these various tools now rests rapidly assimilating our knowledge base into integrated frameworks. Here, we consider how intensive has established basis complex biological environmental networks, which together regulate outcomes severity. We discuss enough scaffold conceptual frameworks underpinning susceptibility, but new are urgently required translate this an operational system informing—and testing—bleaching outcomes. Specifically, adopting network models can fully describe predict metabolic functioning holobionts, is regulated doses interactions among factors. Identifying gaps limiting operation such logical step immediately guide prioritize future experiments observations. at time‐critical point implement capacity resolve patterns emerge from biological–environmental so effectively inform evolving ecological social adaptation aimed securing reefs.

Language: Английский

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Thirty years of coral heat-stress experiments: a review of methods

Coral Reefs, Journal Year: 2020, Volume and Issue: 39(4), P. 885 - 902

Published: April 24, 2020

Abstract For over three decades, scientists have conducted heat-stress experiments to predict how coral will respond ocean warming due global climate change. However, there are often conflicting results in the literature that difficult resolve, which we hypothesize a result of unintended biases, variation experimental design, and underreporting critical methodological information. Here, reviewed 255 (1) document where when they were on species, (2) assess variability (3) quantify diversity response variables measured. First, found two-thirds studies only countries, species more heavily studied than others, 4% focused earlier life stages. Second, slightly half all exposures less 8 d duration, 17% fed corals, conditions varied widely, including level rate temperature increase, light intensity, number genets used, length acclimation period. In addition, 95%, 55%, > 35% did not report tank flow conditions, light–dark cycle or date experiment, respectively. Finally, 21% measure any bleaching phenotype traits, 77% identify Symbiodiniaceae endosymbiont, contribution host physiological was investigated. This review highlights geographic, taxonomic, duration biases our understanding bleaching, large reporting design could account for some discrepancies literature. Development best practice recommendations improve cross-studies comparisons increase efficiency research at time it is needed most.

Language: 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, Journal Year: 2024, Volume and Issue: 99(3), P. 715 - 752

Published: Jan. 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).

Language: Английский

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The past, present, and future of coral heat stress studies

Ecology and Evolution, Journal Year: 2019, Volume and Issue: 9(17), P. 10055 - 10066

Published: Aug. 22, 2019

Abstract The global loss and degradation of coral reefs, as a result intensified frequency severity bleaching events, is major concern. Evidence heat stress affecting corals through symbionts consequent was first reported in the 1930s. However, it not until 1998 event that urgency for studies became internationally recognized. Current efforts focus only on examining consequences but also finding strategies to potentially improve thermal tolerance aid reefs survival future climate scenarios. Although initial were limited comparison with modern technological tools, they provided foundation many today's research methods hypotheses. Technological advancements are providing new prospects at rapid pace. Understanding how have evolved important critical assessment their progress. This review summarizes development field date assesses avenues research.

Language: Английский

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Coral Reef Microorganisms in a Changing Climate

iScience, Journal Year: 2020, Volume and Issue: 23(4), P. 100972 - 100972

Published: March 9, 2020

Coral reefs are one of the most diverse and productive ecosystems on planet, yet they have suffered tremendous losses due to anthropogenic disturbances predicted be adversely affected habitats under future climate change conditions. can viewed as microbially driven that rely efficient capture, retention, recycling nutrients in order thrive oligotrophic waters. Microorganisms play vital roles maintaining holobiont health ecosystem resilience environmental stress; however, also key players positive feedback loops intensify coral reef decline, with cascading effects biogeochemical cycles marine food webs. There is an urgent need develop a fundamental understanding complex microbial interactions within their role acclimatization, it important include microorganisms conservation secure for these unique environments.

Language: Английский

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Avenues of reef-building coral acclimatization in response to rapid environmental change

Journal of Experimental Biology, Journal Year: 2021, Volume and Issue: 224(Suppl_1)

Published: Feb. 15, 2021

ABSTRACT The swiftly changing climate presents a challenge to organismal fitness by creating mismatch between the current environment and phenotypes adapted historic conditions. Acclimatory mechanisms may be especially crucial for sessile benthic marine taxa, such as reef-building corals, where change factors including ocean acidification increasing temperature elicit strong negative physiological responses bleaching, disease mortality. Here, within context of multiple stressors threatening organisms, I describe wealth metaorganism response rapid ontogenetic shifts in organism interactions with that can generate plasticity. then highlight need consider evolutionary an adaptive (epi)genetic continuum. Building on definitions these continuum, also present how interplay microbiome, epigenetics parental effects creates additional avenues acclimatization. To under what conditions epigenetic inheritance has more substantial role, propose investigation into offset timing gametogenesis leading different environmental integration times eggs sperm consequences this gamete compatibility. Collectively, non-genetic, yet heritable phenotypic plasticity will have significant ecological implications persistence change. As such, corals ideal time-sensitive models further development our understanding feedback loops multi-player

Language: 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, Journal Year: 2020, Volume and Issue: 117(46), P. 28906 - 28917

Published: Nov. 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.

Language: Английский

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Meta‐analysis of the coral environmental stress response: Acropora corals show opposing responses depending on stress intensity

Molecular Ecology, Journal Year: 2020, Volume and Issue: 29(15), P. 2855 - 2870

Published: July 2, 2020

Abstract As climate change progresses, reef‐building corals must contend more often with suboptimal conditions, motivating a need to understand coral stress response. Here, we test the hypothesis that there is stereotyped transcriptional response enact under all stressful functionally characterized by downregulation of growth, and activation cell death, reactive oxygen species, immunity, protein folding degradation. We analyse RNA‐seq Tag‐Seq data from 14 previously published studies supplement them four new experiments involving different stressors, totaling over 600 gene expression profiles genus Acropora . Contrary expectations, found not one, but two distinct types The type A was observed kinds high‐intensity stress, correlated between independent projects consistent hypothesized correlation projects, irrespective type, supports as general environmental (ESR), blanket solution severely conditions. B lower intensity variable among studies. Unexpectedly, at level individual genes functional categories, broadly opposite Finally, taking advantage breadth set, present contextual annotations for unannotated based on stress‐induced differences across projects.

Language: Английский

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Divergent expression of hypoxia response systems under deoxygenation in reef‐forming corals aligns with bleaching susceptibility

Global Change Biology, Journal Year: 2020, Volume and Issue: 27(2), P. 312 - 326

Published: Nov. 16, 2020

Abstract Exposure of marine life to low oxygen is accelerating worldwide via climate change and localized pollution. Mass coral bleaching mortality have recently occurred where reefs experienced chronic events. However, the mechanistic basis tolerance levels inadequate sustain normal functioning (i.e. hypoxia) whether it contributes susceptibility, remain unknown. We therefore experimentally exposed colonies environmentally resilient Acropora tenuis , a common reef‐building from Great Barrier Reef, deoxygenation–reoxygenation stress that was aligned their natural night–day light cycle. Specifically, treatment involved removing ‘night‐time O 2 buffer’ challenge inherent hypoxia thresholds. RNA‐Seq analysis revealed possess complete active hypoxia‐inducible factor (HIF)‐mediated response system (HRS) homologous other metazoans. As expected, A. exhibited resistance showed strong inducibility HIF target genes in deoxygenation stress. applied this same approach parallel colony selago known be environmnetally susceptible, which conversely phenotype response. This phenotypic divergence accompanied by contrasting gene expression profiles indicative varied effectiveness HIF‐HRS. Based on our analysis, we propose (a) HIF‐HRS central for corals manage (b) key (and wider network) may contribute variation susceptibility. Our suggests heat shock protein (hsp) 70 90 are important further highlights how hsp90 might also affect overcoming metabolic crisis under differences could regulating sensitivity stressors—notably thermal stress—that commonly drive bleaching.

Language: Английский

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Destabilization of mutualistic interactions shapes the early heat stress response of the coral holobiont

Microbiome, Journal Year: 2025, Volume and Issue: 13(1)

Published: Jan. 31, 2025

The stability of the symbiotic relationship between coral and their dinoflagellate algae (Symbiodiniaceae) is disrupted by ocean warming. Although thermal response depends on complex interactions host, Symbiodiniaceae prokaryotes, mechanisms underlying initial destabilization these symbioses are poorly understood. In a 2-month manipulative experiment, we exposed Porites lutea to gradually increasing temperatures corresponding 0-8 degree heating weeks (DHW) assessed holobiont using transcriptomics, microbial 16S rRNA gene sequencing physiological measurements. From early stages heat stress (< 1 DHW), increase in metabolic turnover shifted net heterotrophic state which algal-derived nutrients were insufficient meet host energy demands, resulting reduced performance at DHW. We postulate altered nutrient cycling also affected coral-associated community, with relative abundance Endozoicomonas bacteria declining under stress. Integration responses correlated this decline an expression ADP-ribosylation factor, suggesting that may underlie similar endosymbiotic regulatory processes. thermotolerance holobionts therefore influenced nutritional status its members interactions, identified interdependency highlights importance applying integrative approach guide reef conservation efforts. Video Abstract.

Language: Английский

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