Increasing hypoxia on global coral reefs under ocean warming

Nature Climate Change, Journal Year: 2023, Volume and Issue: 13(4), P. 403 - 409

Published: March 16, 2023

Language: Английский

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The Coral Bleaching Automated Stress System (CBASS): A low‐cost, portable system for standardized empirical assessments of coral thermal limits

Limnology and Oceanography Methods, Journal Year: 2023, Volume and Issue: 21(7), P. 421 - 434

Published: May 27, 2023

Abstract Ocean warming is increasingly affecting marine ecosystems across the globe. Reef‐building corals are particularly affected by warming, with mass bleaching events increasing in frequency and leading to widespread coral mortality. Yet, some can resist or recover from better than others. Such variability thermal resilience could be critical reef persistence; however, scientific community lacks standardized diagnostic approaches rapidly comparatively assess vulnerability prior events. We present Coral Bleaching Automated Stress System (CBASS) as a low‐cost, open‐source, field‐portable experimental system for rapid empirical assessment of thresholds using temperature stress profiles diagnostics. The CBASS consists four eight flow‐through aquaria independent water masses, lighting, individual automated controls capable delivering custom modulating profiles. used conduct daily exposures that typically include 3‐h ramps multiple target temperatures, hold period at 1‐h ramp back down ambient temperature, followed an overnight recovery period. This mimics shallow observed reefs prompts acute heat response serve tool identify putative thermotolerant in‐depth assessments adaptation mechanisms, targeted conservation, possible use restoration efforts. deployable within hours assay up 40 fragments/aquaria/day, enabling high‐throughput, determination genotypes, populations, species, sites framework.

Language: Английский

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Microplastics in the coral ecosystems: A threat which needs more global attention

Ocean & Coastal Management, Journal Year: 2024, Volume and Issue: 249, P. 107012 - 107012

Published: Jan. 17, 2024

Language: Английский

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High temporal resolution of hydrogen peroxide (H2O2) dynamics during heat stress does not support a causative role in coral bleaching

Coral Reefs, Journal Year: 2024, Volume and Issue: 43(1), P. 119 - 133

Published: Jan. 8, 2024

Abstract Human-induced climate change is causing ocean warming that triggers the breakdown of coral–algal symbiosis. The proximate cause this phenomenon, known as coral bleaching, commonly attributed to overproduction reactive oxygen species (ROS) by thermally stressed photosynthetic algal symbionts. However, direct evidence ROS production (e.g., in form H 2 O ) and physiological stress are ultimate bleaching remains ambiguous. Here, we investigated temporal dynamics (O concentrations during induced disentangle from consequence. Microsensors at tissue interface Pocillopora damicornis measured while exposing single nubbins baseline temperatures (30 °C) minor (33 °C), moderate (36 high (39 levels acute heat using Coral Bleaching Automated Stress System (CBASS). We show a temporary decline concentration, accompanied declining efficiency loss Symbiodiniaceae pigmentation, initial response thermal stress. This was neither provoked nor followed an increased concentration interface. A steady light-independent increase only detected stress, resulting complete permanent activity. Our findings do not support connection between photodamage suggest more research on function warranted. notion further substantiated observation additional source , likely oxidative bursts, were common temperature under their occurrence decreased Resolving multifaceted dynamic roles critical better understand holobiont identifying processes underlying

Language: Английский

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Divergent responses of the coral holobiont to deoxygenation and prior environmental stress

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 10

Published: Feb. 1, 2024

Ocean deoxygenation is intensifying globally due to human activities – and emerging as a grave threat coral reef ecosystems where it can cause bleaching mass mortality. However, one of many threats reefs, making essential understand how prior environmental stress may influence responses deoxygenation. To address this question, we examined the holobiont (i.e., host, Symbiodiniaceae, microbiome) in corals with different backgrounds. We outplanted Acropora cervicornis fragments known genotypes from an situ nursery two sites Florida Keys spanning inshore-offshore gradient. After four months, were transferred laboratory, tested differences survivorship, tissue loss, photosynthetic efficiency, Symbiodiniaceae cell density, microbiome composition after persistent exposure oxygen treatments ranging extreme (0.5 mg L -1 ) normoxia (6 ). found that, for short duration study (four days), entire was resistant dissolved (DO) concentrations low 2.0 , but that members decoupled at 0.5 . In most treatment, host showed decreased mortality, lower densities response, microbial taxa remained stable. Although did not major community shifts composition, population abundance some respond. Site history influenced endosymbiont, microbiome, more stressful inshore site showing greater susceptibility subsequent Our reveals respond differently deoxygenation, sensitivity resistance decrease tolerance

Language: Английский

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Local habitat heterogeneity rivals regional differences in coral thermal tolerance

Coral Reefs, Journal Year: 2024, Volume and Issue: 43(3), P. 571 - 585

Published: April 3, 2024

Abstract Variable temperature regimes that expose corals to sublethal heat stress have been recognized as a mechanism increase coral thermal tolerance and lessen bleaching. However, there is need better understand which maximize hardening. Here, standardized assays were used determine the relative of three divergent genera ( Acropora , Pocillopora Porites ) originating from six reef sites representing an increasing gradient annual mean diel fluctuations 1–3 °C day −1 . Bleaching severity dark-acclimated photochemical yield (i.e., F v / m quantified following exposure five treatments ranging 23.0 36.3 °C. The greatest effective dose 50) was found at site with intermediate variability (2.2 ), suggesting optimal priming leads maximal tolerance. Interestingly, least thermally variable (< 1.3 had lower than most (> 2.8 whereas opposite true for responses across taxa. Remarkably, comparisons global studies revealed range in uncovered this study single 5 km) large differences observed vast latitudinal gradients (300–900 km). This finding indicates local gene flow could improve between habitats. climate change continues, intensifying marine heatwaves already compromising enhance bleaching resistance.

Language: Английский

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Hypoxia threatens coral and sea anemone early life stages

Limnology and Oceanography, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 21, 2025

Abstract Seawater hypoxia is increasing globally and can drive declines in organismal performance across a wide range of marine taxa. However, the effects on early life stages (e.g., larvae juveniles) are largely unknown, it unclear how evolutionary histories may influence these outcomes. Here, we addressed this question by comparing responses three cnidarian species representing histories: reef‐building coral Galaxea fascicularis , broadcast spawner with horizontal transmission endosymbiotic algae (family Symbiodiniaceae); Porites astreoides brooder vertical endosymbiont transmission; estuarine sea anemone Nematostella vectensis non‐symbiotic spawner. Transient exposure to (dissolved oxygen < 2 mg L −1 for 6 h) led decreased larval swimming growth all species, which resulted impaired settlement corals. Coral‐specific also included swelling, depressed respiration rates, decreases symbiont densities function. These results indicate both immediate latent negative physiology coral–algal mutualisms specifically. In addition, G. P. were sensitized heat stress following exposure, suggesting that combinatorial nature climate stressors will lead declining sensitization was not observed N. exposed hypoxia, be more resilient combined stressors. Overall, emphasize importance reducing anthropogenic carbon emissions limit further ocean deoxygenation warming.

Language: Английский

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Considerations for determining warm-water coral reef tipping points

Earth System Dynamics, Journal Year: 2025, Volume and Issue: 16(1), P. 275 - 292

Published: Feb. 7, 2025

Abstract. Warm-water coral reefs are facing unprecedented human-driven threats to their continued existence as biodiverse functional ecosystems upon which hundreds of millions people rely. These impacts may drive past critical thresholds, beyond the system reorganises, often abruptly and potentially irreversibly; this is what Intergovernmental Panel on Climate Change (IPCC, 2022) define a tipping point. Determining point thresholds for reef requires robust assessment multiple stressors interactive effects. In perspective piece, we draw recent global revision initiative (Lenton et al., 2023a) literature search identify summarise diverse range interacting that need be considered determining warm-water ecosystems. Considering observed projected stressor impacts, endorse revision's conclusion mean surface temperature (relative pre-industrial) threshold 1.2 °C (range 1–1.5 °C) long-term atmospheric CO2 concentrations above 350 ppm, while acknowledging comprehensive stressors, including ocean warming response dynamics, overshoot, cascading have yet sufficiently realised. already been exceeded, therefore these systems in an overshoot state reliant policy actions bring levels back within limits. A fuller likely further lower most cases. Uncertainties around points such crucially important underline imperative and, case knowledge gaps, employing precautionary principle favouring lower-range values.

Language: Английский

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Ecosystem Microbiology of Coral Reefs

Coral reefs of the world, Journal Year: 2025, Volume and Issue: unknown, P. 131 - 144

Published: Jan. 1, 2025

Language: Английский

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Remotely sensing coral bleaching in the Red Sea

Remote Sensing in Ecology and Conservation, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Abstract Coral bleaching, often triggered by oceanic warming, has a devastating impact on coral reef systems, resulting in substantial alterations to biodiversity and ecosystem services. For conservation management, an effective technique is needed not only detect monitor bleaching events but also predict their severity levels. By combining high‐resolution satellite measurements (Sentinel‐2 Multispectral Instrument) bottom reflectance model within least‐squares approach, we developed new ocean color remote‐sensing specifically designed detect, map, levels (low high) of at high spatial resolution 10 m. The proposed algorithm was implemented tested the Red Sea compared remarkably well with concurrent independent situ data. We applied investigate response corals during after event Wadi El‐Gemal region (Egypt) from July December 2020. Our results show that sea surface temperature (SST) were unusually August–September After event, signal decreased concurrently SST October–November 2020, aligned recovery bleached reefs offers cost‐effective approach toward developing near‐real‐time system for monitoring multi‐reef scales. Such tools would aid policymakers managers implementing integrated management strategies conservation, as supporting reactive plans, including identification priority areas intervention.

Language: Английский

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