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

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: March 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.

Language: Английский

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The Thermal Stress History of South Atlantic Reefs Reveals Increasing Intensity, Duration, Frequency, and Likely Undocumented Bleaching Episodes

Global Change Biology, Journal Year: 2025, Volume and Issue: 31(4)

Published: April 1, 2025

The primary consequence of global warming for reefs is coral bleaching, often leading to extensive mortality. Although bleaching well-documented globally, the thermal stress and experienced by unique South Atlantic remain largely unknown due insufficient monitoring on both spatial temporal scales. Therefore, this work aimed reconstruct past episodes across reefs, assessed whether are becoming more intense, longer-lasting, frequent. We retrieved daily 5 km-resolution Degree Heating Week (DHW) data from U.S. National Oceanic Atmospheric Administration Coral Reef Watch server 33 reef sites spanning last 40 years. For each episode, we intensity (maximum DHW value), duration (number continuous days under stress), frequency between episodes). Generalized linear models were fitted intensity, duration, evaluate influence latitude time x region interaction as predictors. recorded multiple episodes, increasing 2010 onwards, ranging 10 1985-89 75 2020-24. Intensity increased over entire Atlantic. Frequency also Southwestern coast oceanic islands, but not Africa. Episodes at higher latitudes prolonged, validity history reconstruction was groundtruthed using information Abrolhos Bank, only consistently monitored site in Atlantic-DHW accurately matched observed site. With this, our dataset shows that likely occurred Atlantic, went undocumented field. currently available underestimates extent occurring area, which experiencing increases stress.

Language: Английский

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

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2022, Volume and Issue: 289(1981)

Published: Aug. 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.

Language: Английский

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Emergent increase in coral thermal tolerance reduces mass bleaching under climate change

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Aug. 22, 2023

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 assemblages at a rate 0.1 °C/decade for remote Pacific reef system. This led less severe impacts than would have been predicted otherwise, indicating adaptation, acclimatisation or shifts community structure. Using projections, show that if continues rise over coming century most-likely historic rate, substantial reductions trajectories are possible. High-frequency be fully mitigated some reefs low-to-middle emissions scenarios, only delayed high scenarios. Collectively, our results indicate potential ecological resilience but still highlight reducing carbon line Paris Agreement commitments preserve

Language: Английский

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Increase in the extent of mass coral bleaching over the past half-century, based on an updated global database

PLoS ONE, Journal Year: 2023, Volume and Issue: 18(2), P. e0281719 - e0281719

Published: Feb. 13, 2023

The recurrence of mass coral bleaching and associated mortality in the past few decades have raised questions about future reef ecosystems. Although is well studied, our understanding spatial extent events continues to be limited by geographical biases data collection. To address this gap, we updated a previous observational database spatially modelled probability occurrence. First, an existing raw was cover 1963–2017 period using searches academic grey literature outreach monitoring organizations. Then, order provide spatially-explicit global coverage, employed indicator kriging model occurrence each year from 1985 through 2017 at 0.05° x lat-long resolution. has 37,774 observations, including 22,650 positive reports, three times that version. interpolation suggests 71% world’s reefs likely (>66% probability) experienced least once during period. mean across all globally 29–45% most severe years 1998, 2005, 2010 2016. Modelled probabilities were positively related with annual maximum Degree Heating Weeks (DHW), measure thermal stress, (p<0.001), event (p<0.01). In addition, DHW cells very (>90% increased over time rate cells, suggesting possible increase tolerance. interpolated databases can used other researchers enhance real-time predictions, calibrate models for projections, assess change response stress time.

Language: Английский

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No apparent trade-offs associated with heat tolerance in a reef-building coral

Communications Biology, Journal Year: 2023, Volume and Issue: 6(1)

Published: April 12, 2023

Abstract As marine species adapt to climate change, their heat tolerance will likely be under strong selection. Yet trade-offs between 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 heatwave-induced mass bleaching mortality. Here, we exposed 70 colonies of the coral Acropora digitifera a long-term heatwave emulation experiment. We tested three measured from in situ – colony growth, fecundity, symbiont community composition. Despite observing remarkable within-population variability tolerance, all were dominated by Cladocopium C40 symbionts. found no evidence fecundity growth. Contrary expectations, positive associations emerged with that faster-growing tended bleach die at higher levels stress. Collectively, our results suggest these corals exist on an energetic continuum where some high-performing individuals excel across multiple traits. Within populations, growth may not major barriers success evolution interventions.

Language: Английский

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Diversification of refugia types needed to secure the future of coral reefs subject to climate change

Conservation Biology, Journal Year: 2023, Volume and Issue: 38(1)

Published: May 5, 2023

Abstract Identifying locations of refugia from the thermal stresses climate change for coral reefs and better managing them is one key recommendations adaptation. We review summarize approximately 30 years applied research focused on identifying to prioritize conservation actions under rapid change. found that currently proposed predicted avoid future losses are highly reliant excess heat metrics, such as degree heating weeks. However, many existing alternative environmental, ecological, life‐history variables could be used identify other types lead desired diversified portfolio reef conservation. To improve priorities reefs, there a need evaluate validate predictions with long‐term field data abundance, diversity, functioning. There also safeguard displaying resistance toprolonged exposure waves ability recover quickly after exposure. recommend using more metrics potential sites can avoid, resist, high ocean temperatures consequences change, thereby shifting past efforts avoidance risk‐spreading strategic in rapidly warming climate.

Language: Английский

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Re(de)fining degree-heating week: coral bleaching variability necessitates regional and temporal optimization of global forecast model stress metrics

Coral Reefs, Journal Year: 2024, Volume and Issue: 43(4), P. 969 - 984

Published: June 12, 2024

Abstract Tropical coral reefs are a critical ecosystem in global peril as result of anthropogenic climate change, and effective conservation efforts require reliable methods for identifying predicting bleaching events. To this end, temperature threshold-based models such the National Oceanic Atmospheric Administration’s (NOAA) degree-heating week (DHW) metric useful forecasting function heat stress accumulation. DHW does not adequately account regional variation responses, however, current definition consistently underpredicts occurrence. Using weather skill-based framework, our analysis cross-tested 1080 variations DHW-based occurrence (presence/absence) model against 22 years contemporary observations (1998–2019) order to optimize forecast skill at different levels geographic specificity. On basis relative definition, reducing 1 °C warming cutoff 0.4 °C, adjusting accumulation window 11 weeks, defining threshold 3 improved by 70%. Allowing new definitions vary across regions ocean basins further doubled skill. Our results also suggest that most change over time reef systems respond shifting climate. Since 1998, globally optimized has risen significant rate 0.19 DHW/year, matching pace warming. The trajectory each basin varies. Though work is necessary parse mechanism behind trend, dynamic nature responses demands tools be continuously refined if they inform marine efforts.

Language: Английский

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High coral heat tolerance at local-scale thermal refugia

PLOS Climate, Journal Year: 2024, Volume and Issue: 3(7), P. e0000453 - e0000453

Published: July 11, 2024

Marine heatwaves and mass bleaching have devastated coral populations globally, yet severity often varies among reefs. To what extent a reef’s past exposure to heat stress influences mortality remains uncertain. Here we identify persistent local-scale hotspots thermal refugia the reefs of Palau, Micronesia, based on 36 years satellite-derived cumulative (degree heating weeks–DHW, units: °C-weeks). One possibility is that may harbour more tolerant corals due acclimatisation, directional selection, and/or loss genotypes. Historic patterns assemblage-wide marine align with this hypothesis, DHW-bleaching responses occurring at 1.7°C-weeks greater than refugia. This trend was consistent weaker for Acropora corymbose , severe risk reduced by 4–10% hotspots. However, find contrasting pattern digitifera exposed simulated heatwave. Fragments 174 colonies were collected from replicate hotspot refugium outer comparable wave depth. Higher tolerance (+0.7°C-weeks) correlation tissue biomass suggests factors other DHW overwhelm any spatially varying effects exposure. Further, found considerable A . variability across sites; compared least-tolerant 10% colonies, most-tolerant could withstand additional stresses 5.2 4.1°C-weeks hotspots, respectively. Our study demonstrates do not necessarily nearby refugia, predict species responses. nuance has important implications designing climate-smart initiatives; instance, in search corals, our results suggest investing effort into identifying most within individual be warranted.

Language: Английский

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Appraisal of coral bleaching thresholds and thermal projections for the northern Red Sea refugia

Frontiers in Marine Science, Journal Year: 2022, Volume and Issue: 9

Published: Nov. 22, 2022

Corals in the northern Red Sea exhibit high thermal tolerance despite increasing heat stress. It is assumed that corals throughout have similar bleaching thresholds (32°C or higher), and hence greater of region likely due to lower ambient water temperatures (25–28°C) remain well below corals’ physiological maxima. Whether patterns across are independent local maximum monthly mean seawater temperature aligned with an 32°C threshold has yet be determined. Here, we used remotely sensed surface sea data spanning 1982–2020 model spatial distributions Degree Heat Weeks relation coral values 30, 31, 32°C. We also Coupled Model Intercomparison Project Phase 5 outputs predict warming trends under different greenhouse gas representative concentration pathways (RCPs). show applying dramatically reduces effective north, but not central southern regions, a finding consistent historical observations (1998–2020) Sea. Further, predictions most extreme RCP8.5 scenario exhibited ~3°C by end 21 st century less pronounced for (2–2.5°C) compared regions (2.7–3.1°C).This rate will which should help this serve as refugia (i.e., maintaining favorable temperatures) persist decades ahead. Together, our results support notion Sea; hence, mean. Consequently, where regional projections suggest reach (32°C) before century, reefs may among last standing against climate change.

Language: Английский

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