Heat stress destabilizes symbiotic nutrient cycling in corals

Proceedings of the National Academy of Sciences, Год журнала: 2021, Номер 118(5)

Опубликована: Янв. 26, 2021

Recurrent mass bleaching events are pushing coral reefs worldwide to the brink of ecological collapse. While symptoms and consequences this breakdown coral-algal symbiosis have been extensively characterized, our understanding underlying causes remains incomplete. Here, we investigated nutrient fluxes physiological as well molecular responses widespread Stylophora pistillata heat stress prior onset identify processes involved in symbiosis. We show that altered cycling during is a primary driver functional Heat increased metabolic energy demand host, which was compensated by catabolic degradation amino acids. The resulting shift from net uptake release ammonium holobiont subsequently promoted growth algal symbionts retention photosynthates. Together, these form feedback loop will gradually lead decoupling carbon translocation symbiont host. Energy limitation symbiotic thus key factors early response, directly contributing Interpreting stability light its interactions provides missing link environmental drivers may ultimately help uncover fundamental underpinning functioning endosymbioses general.

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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Mechanisms and Impacts of Earth System Tipping Elements

Reviews of Geophysics, Год журнала: 2023, Номер 61(1)

Опубликована: Фев. 16, 2023

Abstract Tipping elements are components of the Earth system which may respond nonlinearly to anthropogenic climate change by transitioning toward substantially different long‐term states upon passing key thresholds or “tipping points.” In some cases, such changes could produce additional greenhouse gas emissions radiative forcing that compound global warming. Improved understanding tipping is important for predicting future risks and their impacts. Here we review mechanisms, predictions, impacts, knowledge gaps associated with 10 notable proposed be elements. We evaluate approaching critical whether shifts manifest rapidly over longer timescales. Some have a higher risk crossing points under middle‐of‐the‐road pathways will possibly affect major ecosystems, patterns, and/or carbon cycling within 21st century. However, literature assessing scenarios indicates strong potential reduce impacts many through mitigation. The studies synthesized in our suggest most do not possess abrupt years, exhibit behavior, rather responding more predictably directly magnitude forcing. Nevertheless, uncertainties remain elements, highlighting an acute need further research modeling better constrain risks.

Язык: Английский

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Hidden heatwaves and severe coral bleaching linked to mesoscale eddies and thermocline dynamics

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Янв. 6, 2023

Abstract The severity of marine heatwaves (MHWs) that are increasingly impacting ocean ecosystems, including vulnerable coral reefs, has primarily been assessed using remotely sensed sea-surface temperatures (SSTs), without information relevant to heating across ecosystem depths. Here, a rare combination SST, high-resolution in-situ temperatures, and sea level anomalies observed over 15 years near Moorea, French Polynesia, we document subsurface MHWs have paradoxical in comparison SST metrics associated with unexpected bleaching Variations the depth range was driven by mesoscale (10s 100s km) eddies altered levels thermocline depths decreased (2007, 2017 2019) or increased (2012, 2015, 2016) internal-wave cooling. Pronounced eddy-induced reductions internal waves during early 2019 contributed prolonged MHW unexpectedly severe bleaching, subsequent mortality offsetting almost decade recovery. Variability eddy fields, thus depths, is expected increase climate change, which, along strengthening deepening stratification, could occurrence ecosystems historically insulated from surface cooling effects waves.

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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Systematic review of the uncertainty of coral reef futures under climate change

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Март 12, 2024

Abstract Climate change impact syntheses, such as those by the Intergovernmental Panel on Change, consistently assert that limiting global warming to 1.5 °C is unlikely safeguard most of world’s coral reefs. This prognosis primarily based a small subset available models apply similar ‘excess heat’ threshold methodologies. Our systematic review 79 articles projecting reef responses climate revealed five main methods. ‘Excess constituted one third (32%) all studies but attracted disproportionate share (68%) citations in field. Most methods relied deterministic cause-and-effect rules rather than probabilistic relationships, impeding field’s ability estimate uncertainty. To synthesize projections, we aimed identify with comparable outputs. However, divergent choices model outputs and scenarios limited analysis fraction studies. We found substantial discrepancies projected impacts, indicating serving basis for syntheses may project more severe consequences other Drawing insights from fields, propose incorporate uncertainty into modeling approaches multi-model ensemble approach generating projections futures.

Язык: Английский

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Highest ocean heat in four centuries places Great Barrier Reef in danger

Nature, Год журнала: 2024, Номер 632(8024), С. 320 - 326

Опубликована: Авг. 7, 2024

Mass coral bleaching on the Great Barrier Reef (GBR) in Australia between 2016 and 2024 was driven by high sea surface temperatures (SST)

Язык: Английский

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Turbid Coral Reefs: Past, Present and Future—A Review

Diversity, Год журнала: 2021, Номер 13(6), С. 251 - 251

Опубликована: Июнь 7, 2021

Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led poor representation of these reef types within the scientific literature, with studies using different methods definitions characterize reefs. Here we review geological origins growth histories from Holocene (past), their current ecological environmental states (present), potential responses resilience increasing local global pressures (future). We classify new descriptors based on regime (persistent, fluctuating, transitional) sources sediment input (natural versus anthropogenic). Further, by comparing composition, function two most studied reefs, Paluma Shoals Reef Complex, Australia turbidity) Singapore (anthropogenic turbidity), found them distinct status. As geographic range is expected increase due stressors, improving our understanding will central efforts.

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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Greater functional diversity and redundancy of coral endolithic microbiomes align with lower coral bleaching susceptibility

The ISME Journal, Год журнала: 2022, Номер 16(10), С. 2406 - 2420

Опубликована: Июль 15, 2022

Abstract The skeleton of reef-building coral harbors diverse microbial communities that could compensate for metabolic deficiencies caused by the loss algal endosymbionts, i.e., bleaching. However, it is unknown to what extent endolith taxonomic diversity and functional potential might contribute thermal resilience. Here we exposed Goniastrea edwardsi Porites lutea, two common corals from central Red Sea a 17-day long heat stress. Using hyperspectral imaging, marker gene/metagenomic sequencing, NanoSIMS, characterized their endolithic microbiomes together with 15N 13C assimilation skeletal compartments: band directly below tissue deep skeleton. bleaching-resistant G. was associated greater redundancy exhibited lower N C than endoliths in bleaching-sensitive P. lutea. We propose primary productivity can be attributed dominance chemolithotrophs. Lower production within may prevent unbalanced nutrient fluxes tissues under stress, thereby preserving nutrient-limiting conditions characteristic stable coral-algal symbiosis. Our findings link microbiome structure function bleaching susceptibility, providing new avenues understanding eventually mitigating reef loss.

Язык: Английский

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