Divergent bleaching and recovery trajectories in reef-building corals following a decade of successive marine heatwaves

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(52)

Published: Dec. 19, 2023

Increasingly frequent marine heatwaves are devastating coral reefs. Corals that survive these extreme events must rapidly recover if they to withstand subsequent events, and long-term survival in the face of rising ocean temperatures may hinge on recovery capacity acclimatory gains heat tolerance over an individual’s lifespan. To better understand trajectories successive heatwaves, we monitored responses bleaching-susceptible bleaching-resistant individuals two dominant species Hawai’i, Montipora capitata Porites compressa , a decade included three heatwaves. Bleaching-susceptible colonies P. exhibited beneficial acclimatization stress (i.e., less bleaching) following repeat becoming indistinguishable from conspecifics during third heatwave. In contrast, M. repeatedly bleached all seasonal bleaching substantial mortality for up 3 y Encouragingly, both remained pigmented across entire time series; however, pigmentation did not necessarily indicate physiological resilience. Specifically, displayed incremental yet only partial symbiont density tissue biomass phenotypes 35 mo heatwave as well considerable mortality. Conversely, appeared most metrics within 2 experienced little no Ultimately, results even some visually robust, corals can carry cost recurring multiple years, leading divergent erode reef resilience Anthropocene.

Language: Английский

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Experimental coral reef communities transform yet persist under mitigated future ocean warming and acidification

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(45)

Published: Oct. 29, 2024

Coral reefs are among the most sensitive ecosystems affected by ocean warming and acidification, predicted to collapse over next few decades. Reefs shift from net accreting calcifier-dominated systems with exceptionally high biodiversity eroding algal-dominated dramatically reduced biodiversity. Here, we present a two-year experimental study examining responses of entire mesocosm coral reef communities (+2 °C), acidification (-0.2 pH units), combined future °C, -0.2 pH) treatments. Contrary modeled projections, show that under conditions, these structure composition yet persist as novel calcifying Our results suggest if climate change is limited Paris Climate Agreement targets, could in an altered state rather than collapse.

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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Coral histology reveals consistent declines in tissue integrity during a marine heatwave despite differences in bleaching severity

PeerJ, Journal Year: 2025, Volume and Issue: 13, P. e18654 - e18654

Published: Jan. 3, 2025

Marine heatwaves are starting to occur several times a decade, yet we do not understand the effect this has on corals across biological scales. This study combines tissue-, organism-, and community-level analyses investigate effects of marine heatwave reef-building corals. Adjacent conspecific pairs coral colonies Montipora capitata Porites compressa that showed contrasting phenotypic responses ( i.e. , bleached vs . bleached) were first identified during occurred in 2015 Kāne’ohe Bay, Hawai‘ i. These bleaching-resistant bleaching-susceptible sampled for histology photographed before, during, after subsequent 2019. Histology samples quantified for: (i) abundance mesenterial filaments, (ii) tissue structural integrity, (iii) clarity epidermis, (iv) cellular integrity (lack necrosis/granulation) 1–5 scale averaged an overall score. Tissue scores revealed significant decline health 2019 relative months prior individuals both species, regardless past bleaching history or severity heatwave. Coral then compared concurrent colony severity, which was significantly correlated with suggests stability symbiosis is related host health. Colony partial mortality also as cumulative proportion each appeared dead 2.5 years following event, found be strongly predictive extent M. but P. latter suffered little no mortality. Surprisingly, either suggesting better predictor than Despite negative heat stress at tissue- colony-level, changes cover detected, indicating resilience community level. However, declines response accompanied by visible may still have long-term consequences fitness, important area future investigation commonly associated decreases fecundity growth. Our results suggest valuable tool revealing harmful before they visually evident bleaching, thus improve predictability ecosystem climate change-driven providing more comprehensive assessment

Language: Английский

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Parental effects provide an opportunity for coral resilience following major bleaching events

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(1), P. e0290479 - e0290479

Published: Jan. 7, 2025

Identifying processes that promote coral reef recovery and resilience is crucial as ocean warming becomes more frequent severe. Sexual reproduction essential for the replenishment of populations maintenance genetic diversity; however, ability corals to reproduce may be impaired by marine heatwaves cause bleaching. In 2014 2015, Hawaiian Islands experienced bleaching with differential susceptibility in species Montipora capitata , a dominant reef-building region. We tested hypothesis resistance enhances reproductive capacity offspring performance examining biology colonies bleached recovered (B) did not bleach (NB) 2015 subsequent spawning seasons. The proportion spawned was higher 2016 than 2017. Regardless parental history, we found eggs abnormality bundles fewer While output similar between B NB 2016, survivorship year were significantly influenced history (egg donor × sperm donor: B, NB, NB). Offspring produced egg donors had highest survivorship, while from previously lowest highlighting negative effects on investment performance. sexual continues M . post-bleaching, gametes are differentially impacted time following event resistance. Our results demonstrate importance identifying resistant individuals during after heating events. This study further highlights significance maternal through potential provisioning provides baseline human-assisted intervention (i.e., selective breeding) mitigate climate change reefs.

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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Homogenization and distinction of coral recruit communities between natural and artificial substrates at Koh Tao a decade after deployment

Aquatic Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

Language: Английский

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Evidence of rare occurrences of the Phoenix effect in the Hawaiian corals Porites compressa and Montipora capitata following mortality induced by a marine heatwave

PeerJ, Journal Year: 2025, Volume and Issue: 13, P. e19225 - e19225

Published: April 15, 2025

Coral bleaching is a common stress response to extreme temperatures experienced during marine heatwaves. Bleached corals are left vulnerable without the nutritional support of their algal symbionts, and can often suffer partial or complete mortality. Bleaching-induced mortality accompanied by colonization turf algae over dead coral skeleton, which be difficult for regrow over. The Phoenix effect phenomenon rapid recovery live tissue following mortality, hypothesized occur via regrowth from deep within skeleton that expands top portions. Here, we found Hawaiian Porites compressa Montipora capitata display suggestive effect. During heatwave occurred in 2015 Kāne’ohe Bay, Hawai’i, USA, 237 individuals (including bleached non-bleached phenotypes) were identified monitored next 2–7 years. Nearly 16% P. 34% M. exhibited substantial approximately half these affected each species had heatwave. Partial was followed exposed skeleton. Of colonies with six (10% individuals; five one ) subsequently recovered 90% 2 years (2017), an additional three (two recovering 4 (2019). We qualify as those meet two criteria: (1) (≥40%) first 12 months initial heatwave, (2) any amount at anytime before 2022. Interestingly, only recovery. A consecutive, yet less severe 2019, none previously observed significant loss, suggesting remained resilient amidst secondary heat exposure. This example remarkable resilience may informative further study mechanisms regeneration important reef-building species.

Language: Английский

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Coral larvae increase nitrogen assimilation to stabilize algal symbiosis and combat bleaching under increased temperature

PLoS Biology, Journal Year: 2024, Volume and Issue: 22(11), P. e3002875 - e3002875

Published: Nov. 12, 2024

Rising sea surface temperatures are increasingly causing breakdown in the nutritional relationship between corals and algal endosymbionts (Symbiodiniaceae), threatening basis of coral reef ecosystems highlighting critical role reproduction maintenance. The effects thermal stress on metabolic exchange (i.e., transfer fixed carbon photosynthates from symbiont to host) during sensitive early life stages, however, remains understudied. We exposed symbiotic Montipora capitata larvae Hawaiʻi high temperature (+2.5°C for 3 days), assessed rates photosynthesis respiration, used stable isotope tracing (4 mM 13 C sodium bicarbonate; 4.5 h) quantify metabolite exchange. While did not show any signs bleaching experience declines survival settlement, depression was significant under temperature, indicated by a 19% reduction respiration rates, but with no change photosynthesis. Larvae showed evidence maintained translocation major photosynthate, glucose, symbiont, there reduced metabolism glucose through central glycolysis). larval host invested nitrogen cycling increasing ammonium assimilation, urea metabolism, sequestration into dipeptides, mechanism that may support maintenance stress. Host assimilation via dipeptide synthesis appears be limitation Symbiodiniaceae, we hypothesize contributes retention favoring photosynthate host. Collectively, our findings indicate although these susceptible diverting energy maintain population density, photosynthesis, allow avoid highlights potential stage specific responses

Language: Английский

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Physiological and symbiotic flexibility of reef‐building corals to new habitats: Insights from clonal colony transplants

Journal of Applied Ecology, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 15, 2024

Abstract Global decline of coral reefs shows varied responses to environmental stress, highlighting the need understand these differences. The physiological plasticity hosts and their microalgal symbionts can allow holobiont thrive in diverse marine environments, suggesting new strategies for effective restoration. To investigate local influence on physiology two Caribbean species ( Acropora palmata Orbicella faveolata ), clonal colonies from a land‐based nursery were transferred nearshore offshore one year. After transfer reef habitats, both shifted photopigmentation host energy reserves. also dominant altered growth. Stable isotopes identified higher autotrophic proportions metabolic carbon photosynthesis rates transplanted compared those nursery. Synthesis applications . These findings improve our understanding acclimatization plasticity, potential side effects domestication. As restoration accelerates globally, this knowledge is crucial guiding efforts conserving endangered ecosystems by supplying considerations improving coral‐rearing systems providing information genera‐specific transplant sites.

Language: Английский

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