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

---

Predicting Responses of Geo-ecological Carbonate Reef Systems to Climate Change: A Conceptual Model and Review

CRC Press eBooks, Journal Year: 2021, Volume and Issue: unknown, P. 229 - 370

Published: Sept. 22, 2021

230Coral reefs provide critical ecological and geomorphic (e.g. sediment production for reef-fronted shoreline maintenance) services, which interact in complex dynamic ways. These services are under threat from climate change, requiring modelling approaches that predict how reef systems will respond to different future scenarios. Carbonate budgets, estimate net calcium carbonate production, a comprehensive 'snap-shot' assessment of accretionary potential stability. however, were not intended account the full suite processes maintain coral or predictive capacity on longer timescales (decadal centennial). To dual challenges enhancing budget assessments advancing their capacity, we applied novel model elicitation review method create qualitative geo-ecological system links geomorphic, physical processes. Our approach conceptualizes relationships between transport landform stability, rates knowledge confidence reveal major gaps research pathways. The provides blueprint aims quantify dynamics, improving our responses shorelines change.

Language: Английский

---

Eutrophication on Coral Reefs: What Is the Evidence for Phase Shifts, Nutrient Limitation and Coral Bleaching

BioScience, Journal Year: 2021, Volume and Issue: 71(12), P. 1216 - 1233

Published: Sept. 8, 2021

Abstract Coral reefs continue to experience extreme environmental pressure from climate change stressors, but many coral are also exposed eutrophication. It has been proposed that changes in the stoichiometry of ambient nutrients increase mortality corals, whereas eutrophication may facilitate phase shifts macroalgae-dominated when herbivory is low or absent. But corals ever nutrient limited, and can destabilize symbiosis making it more sensitive stress because change? The effects confounded not just by presence chemical pollutants industrial, urban, agricultural wastes. Because these confounding effects, increases their coastal environments, although they important at organismal community level, cannot currently be disentangled each other significant stressors on reefs.

Language: Английский

---

Cloudiness reduces the bleaching response of coral reefs exposed to heat stress

Global Change Biology, Journal Year: 2021, Volume and Issue: 27(15), P. 3474 - 3486

Published: May 9, 2021

Abstract Climate change and warming ocean temperatures are a threat to coral reef ecosystems. Since the 1980s, there has been an increase in mass bleaching associated mortality due more frequent severe thermal stress. Although most research focused on role of temperature, is product interacting effects temperature other environmental variables such as solar radiation. High light exacerbates stress corals, whereas reductions can reduce sensitivity Here, we use updated global dataset observations ( n = 35,769) from 1985 2017 satellite‐derived datasets SST clouds examine for first time at scale influence cloudiness likelihood We find that among reefs exposed bleaching‐level heat (Degree Heating Weeks >8°Cˑweek), severity inversely correlated with interaction cloud fraction anomalies p < 0.05), higher implies reduced response. A Random Forest model analysis employing different set shows Degree 30‐day anomaly accurately predicts (Accuracy 0.834; Cohen's Kappa 0.769). Based these results warm‐season patterns, develop ‘cloudy refugia’ index which identifies central equatorial Pacific French Polynesia regions where likely protect corals bleaching. Our findings suggest incorporating into prediction models help delineate responses identify may be resilient climate change.

Language: Английский

---

The past, present, and future of coral reef growth in the Florida Keys

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(17), P. 5294 - 5309

Published: July 5, 2022

Coral-reef degradation is driving global-scale reductions in reef-building capacity and the ecological, geological, socioeconomic functions it supports. The persistence of those essential will depend on whether coral-reef management able to rebalance competing processes reef accretion erosion. Here, we reconstructed census-based carbonate budgets 46 reefs throughout Florida Keys from 1996 2019. We evaluated environmental ecological drivers changing budget states compared historical trends reef-accretion potential millennial-scale baselines cores future projections with coral restoration. found that historically, most had positive budgets, many comparable ~3 mm year-1 average rate during peak regional building ~7000 years ago; however, declines Acropora palmata Orbicella spp. corals following a series thermal stress events disease outbreaks resulted shift negative for region. By 2019, only ~15% net production. Most were inshore, Lower patch-reef habitats low water clarity, supporting hypothesis environments naturally irradiance may provide refugia stress. caution our estimated are likely overly optimistic; comparison measured suggests that, by not accounting role nonbiological physical chemical erosion, underestimate total erosion ~1 (-1.15 kg CaCO3 m-2 ). Although present state Florida's dire, demonstrate restoration has help mitigate some locations, which could allow key ecosystem be maintained until threat global climate change addressed.

Language: Английский

---