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

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

Published: Jan. 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.

Language: Английский

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Oceanic differences in coral-bleaching responses to marine heatwaves

The Science of The Total Environment, Journal Year: 2023, Volume and Issue: 871, P. 162113 - 162113

Published: Feb. 9, 2023

Anomalously high ocean temperatures have increased in frequency, intensity, and duration over the last several decades because of greenhouse gas emissions that cause global warming marine heatwaves. Reef-building corals are sensitive to such temperature anomalies commonly lead coral bleaching, mortality, changes community structure. Yet, despite these overarching effects, there geographical differences thermal regimes, evolutionary histories, past disturbances may different bleaching responses within among oceans. Here we examined overall Atlantic, Indian, Pacific Oceans, using both a spatially explicit Bayesian mixed-effects model deep-learning neural-network model. We used 40-year dataset encompassing 23,288 coral-reef surveys at 11,058 sites 88 countries, from 1980 2020. Focusing on ocean-wide assessed relationships between percentage bleached temperature-related metrics alongside suite environmental variables. found while sea-surface were consistently, strongly, related all oceans, clear most For instance, was an increase with depth Atlantic Ocean whereas opposite observed Indian Ocean, no trend could be seen Ocean. The standard deviation thermal-stress negatively but not Globally, has progressively occurred higher four although, again, three Together, patterns highlight historical circumstances oceanographic conditions play central role contemporary coral-bleaching responses.

Language: Английский

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Mesophotic coral bleaching associated with changes in thermocline depth

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

Published: Oct. 16, 2023

As global temperatures continue to rise, shallow coral reef bleaching has become more intense and widespread. Mesophotic ecosystems reside in deeper (30-150 m), cooler water were thought offer a refuge shallow-water reefs. Studies now show that mesophotic instead have limited connectivity with corals but host diverse endemic communities. Given their extensive distribution high biodiversity, understanding susceptibility warming oceans is imperative. In this multidisciplinary study of an atoll the Chagos Archipelago central Indian Ocean, we evidence at 90 m, despite absence bleaching. We also was associated sustained thermocline deepening driven by Ocean Dipole, which might be further enhanced internal waves whose influence varied sub-atoll scale. Our results demonstrate potential vulnerability thermal stress highlight need for oceanographic knowledge predict heterogeneity.

Language: Английский

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Viruses of a key coral symbiont exhibit temperature-driven productivity across a reefscape

ISME Communications, Journal Year: 2023, Volume and Issue: 3(1)

Published: April 3, 2023

Abstract Viruses can affect coral health by infecting their symbiotic dinoflagellate partners (Symbiodiniaceae). Yet, viral dynamics in colonies exposed to environmental stress have not been studied at the reef scale, particularly within individual lineages. We sequenced major capsid protein (mcp) gene of positive-sense single-stranded RNA viruses known infect dinoflagellates (‘dinoRNAVs’) analyze reef-building coral, Porites lobata. repeatedly sampled 54 harboring Cladocopium C15 dinoflagellates, across three environmentally distinct zones (fringing reef, back and forereef) around island Moorea, French Polynesia over a 3-year period spanning reef-wide thermal event. By end sampling period, 28% (5/18) corals fringing experienced partial mortality versus 78% (14/18) forereef. Over 90% (50/54) had detectable dinoRNAV infections. Reef zone influenced composition richness mcp amino acid types (‘aminotypes’), with containing highest aminotype richness. The event significantly increased dispersion, this pattern was strongest that mortality. These findings demonstrate infections respond fluctuations situ on reefs. Further, productivity will likely increase as ocean temperatures continue rise, potentially impacting foundational symbiosis underpinning ecosystems.

Language: Английский

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Variability in thermal stress thresholds of corals across depths

Frontiers in Marine Science, Journal Year: 2023, Volume and Issue: 10

Published: Sept. 14, 2023

Mesophotic habitats are potential refugia for corals in the context of climate change. The seawater temperature a mesophotic habitat is generally lower than shallow habitat. However, susceptibility and threshold temperatures not well understood. We compared 11 species to understand their thermal stress thresholds using physiological parameters. Coral fragments were exposed two treatments, with set at ~30°C ~31°C, low-temperature treatment ~28°C as “no stress” condition 14 days. found that coral depths slightly or equal depths. results suggest ecosystems can survive low (<4 degree heating weeks) stress. mass bleaching high mortality be expected when rise above 4 weeks.

Language: Английский

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First characterization of upper mesophotic coral assemblages in Santo Antão (Cabo Verde, East Atlantic Ocean): Demographic and community approaches provide baseline ecological data

Progress In Oceanography, Journal Year: 2025, Volume and Issue: unknown, P. 103432 - 103432

Published: Feb. 1, 2025

Language: Английский

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Depth variation in benthic community response to repeated marine heatwaves on remote Central Indian Ocean reefs

Royal Society Open Science, Journal Year: 2024, Volume and Issue: 11(3)

Published: March 1, 2024

Coral reefs are increasingly impacted by climate-induced warming events. However, there is limited empirical evidence on the variation in response of shallow coral reef communities to thermal stress across depths. Here, we assess depth-dependent changes benthic following successive marine heatwaves from 2015 2017 a 5–25 m depth gradient remote Chagos Archipelago, Central Indian Ocean. Our analyses show an overall decline hard and soft cover increase crustose coralline algae, sponge pavement system. findings indicate that elevated seawater temperatures varied We found greater group at depths (5–15 m) compared with deeper zones (15–25 m). The loss was better predicted initial stress, while associated repeated study shows extending 25 were heatwaves, supporting concerns about resilience severe climate-driven

Language: Английский

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The effect of depth on the composition and saturation of total fatty acids present within the tissues and skeletons of two reef-building corals

Marine Biology, Journal Year: 2025, Volume and Issue: 172(5)

Published: April 3, 2025

Language: Английский

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Characterizing the extent of the oceanic 60–150 m deep mesophotic zone in Tuamotu-Gambier Archipelago atolls using multibeam bathymetry and geomorphology data

Coral Reefs, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Language: Английский

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Improved coral nursery production through contingent heat stress events via depth manipulation

Aquaculture, Journal Year: 2025, Volume and Issue: unknown, P. 742558 - 742558

Published: April 1, 2025

Language: Английский

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