Deoxygenation lowers the thermal threshold of coral bleaching

Scientific Reports, Journal Year: 2022, Volume and Issue: 12(1)

Published: Oct. 31, 2022

Abstract Exposure to deoxygenation from climate warming and pollution is emerging as a contributing factor of coral bleaching mortality. However, the combined effects heating on susceptibility remain unknown. Here, we employed short-term thermal stress assays show that deoxygenated seawater can lower limit an Acropora by much 1 °C or 0.4 based index scores dark-acclimated photosynthetic efficiencies, respectively. Using RNA-Seq, similar responses heat with without seawater, both activating putative key genes hypoxia-inducible response system indicative cellular hypoxia. We also detect distinct responses, including disruption O 2 -dependent photo-reception/-protection, redox status, activation immune prior onset bleaching. Thus, corals are even more vulnerable when faced in waters. This highlights need integrate dissolved measurements into global monitoring programs reefs.

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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Disparate Inventories of Hypoxia Gene Sets Across Corals Align With Inferred Environmental Resilience

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

Published: May 19, 2022

Aquatic deoxygenation has been flagged as an overlooked but key factor contributing to mass bleaching-induced coral mortality. During events triggered by coastal nutrient pollution and ocean warming, oxygen supplies lower concentrations that can elicit aerobic metabolic crisis i.e., hypoxia. Surprisingly little is known of the fundamental hypoxia gene set inventory corals possess respond lowered (i.e., deoxygenation). For instance, it unclear whether copy number differences exist across species may affect efficacy a measured transcriptomic stress response. Therefore, we conducted ortholog-based meta-analysis investigate how inventories differ amongst assess putative variations (CNVs). We specifically elucidated CNVs for compiled list 32 genes 24 protein sets from with sequenced genome spanning robust complex clade. found approximately third investigated exhibited differences, these were species-specific rather than attributable robust-complex split. Interestingly, consistently highest expansion present in Porites lutea , which considered exhibit inherently greater tolerance other species. Consequently, our analysis suggests coincide increased tolerance. As such, unevenly expanded (or reduced) presented here provide interest target examining diagnosing) responses. Important next steps will involve determining what extent such align certain traits.

Language: Английский

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Intra‐colony spatial variance of oxyregulation and hypoxic thresholds for key Acropora coral species

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(3)

Published: March 1, 2024

Abstract Oxygen (O 2 ) availability is essential for healthy coral reef functioning, yet how continued loss of dissolved O via ocean deoxygenation impacts performance building corals remains unclear. Here, we examine intra‐colony spatial geometry important Great Barrier Reef (GBR) species Acropora may influence variation in hypoxic thresholds upregulation, to better understand capacity tolerate future reductions availability. We first evaluate the application more streamlined models used parameterise Hypoxia Response Curve data, that have been historically identify variable oxyregulatory capacity. Using closed‐system respirometry analyse drawdown rate, show a two‐parameter model returns similar outputs as previous 12th‐order descriptive statistics such average oxyregulation (T pos and ambient level at which exerts maximum regulation effort (P cmax ), diverse species. Following an experiment whether stress induced by fragmentation affected subsequently differences response interior exterior colony locations abrotanoides , cf. microphthalma elseyi . Average across was greater (0.78–1.03 ± SE 0.08) compared with (0.60–0.85 0.08). Moreover, P occurred relatively low p <30% (±1.24; SE) air saturation all species, colony. When against availability, these factors corresponded mean oxyregulation, suggesting lower corresponds higher oxyregulation. Collectively, our data affects thresholds, potentially driving

Language: Английский

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In Vivo Lifetime Imaging of the Internal O₂ Dynamics in Corals with near-Infrared-Emitting Sensor Nanoparticles

ACS Sensors, Journal Year: 2024, Volume and Issue: 9(9), P. 4671 - 4679

Published: Aug. 23, 2024

Mapping of O2 with luminescent sensors within intact animals is challenging due to attenuation excitation and emission light caused by tissue absorption scattering as well interfering background fluorescence. Here we show the application sensor nanoparticles (∼50–70 nm) composed indicator platinum(II) tetra(4-fluoro)phenyltetrabenzoporphyrin (PtTPTBPF) immobilized in poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA). We injected into gastrovascular system colony fractions reef-building tropical corals that harbor photosynthetic microalgae their tissues. The are excited red LED (617 emit near-infrared (780 nm), which enhances transmission through biological materials. This enabled us map internal concentration via time-domain luminescence lifetime imaging outer layers across several coral polyps flowing seawater. After injection, dispersed for hours. While intensity showed some local aggregation particles, a more homogeneous distribution larger area colony. Local stimulation symbiont photosynthesis induced oxygenation illuminated areas formation lateral gradients toward surrounding respiring tissues, were dissipated rapidly after onset darkness. Such measurements key improving our understanding how regulate chemical microenvironment metabolic activity, they affected environmental stress such ocean warming, acidification, deoxygenation. Our experimental approach can also be adapted vivo other natural systems biofilms, plant animal organoids cell constructs, where conditions relevant high optical density

Language: Английский

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Caribbean scleractinian corals exhibit highly variable tolerances to acute hypoxia

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

Published: May 17, 2023

Introduction Climate change, and the increase in sea surface temperature, is exacerbating ocean deoxygenation because of inherent property seawater to sequester less dissolved gas, such as oxygen, at warmer temperatures. While most coral reef studies focus on effects thermal stress acidification, few acknowledge threat hypoxia. Hypoxia traditionally defined 6.3 kPa (2 mg L-1 O2), however, a universal hypoxia threshold not useful given vast range responses among marine organisms. The metabolic tolerances are unknown for Caribbean species their algal symbionts. Objective Here, we quantified spectrum acute six ecologically structurally important (Acropora cervicornis, Siderastrea radians, siderea, Porites astreoides, porites, Orbicella faveolata) symbionts (Symbiodinium, Breviolum, Durusdinium spp.). Methods A total 24 fragments (4 individuals per species) were exposed 10 distinct oxygen concentrations ranging from normoxia (20.38 kPa) severe (3.3 kPa). We used intermittent flow respirometry measure host respiration dark symbiont photosynthesis light each level. determined line best fit rate vs. PO2 data calculated critical partial pressure (PO2 crit), method that has been tested symbiotic species. Results Coral measured here displayed wide tolerances. For hosts, crit values differed roughly two-fold 5.74 16.93 kPa, symbionts, three-fold 3.9 11.3 kPa. Discussion These results should be regarded first step characterizing response tolerance multiple hosts concentrations. Given some above generally accepted threshold, these have implications community composition reefs under rapidly changing climate can guide purposeful restoration.

Language: Английский

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Physiological responses of Pocillopora corals to upwelling events in the Eastern Tropical Pacific

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

Published: July 31, 2023

Upwelling events can change the sea water conditions within few hours during several months on a seasonal regimen. These are predicted to intensify due climate change, exposing shallow benthic organisms hypoxia and thermal stress, among other extreme conditions. Some coral reefs in Eastern Tropical Pacific (ETP) recurrently experience upwelling events. Coral off Gorgona Island, Colombia, exposed lower oxygen concentrations (3.0 - 3.7 mg O 2 L -1 ) temperatures (17 24°C) from mid-January mid-April, when develops, compared rest of year (4.9 ± 0.7 , 28.4 0.3°C, mean SD). While no visible signs stress have been reported for corals upwelling, it be hypothesized that would negatively affected by these changes. Therefore, objectives this study were (1) identify effects temperature metabolic rate (MO Pocillopora under lab conditions, (2) examine changes skeletal growth Symbiodiniaceae density field between non-upwelling seasons. Findings revealed MO was significantly reduced 20% at 24°C increased 10% 32°C 28°C. During season, exhibited 52% increase density, but decreased 50% season. Fast strongly affects metabolism corals. Although not lethal, they compromised energy their vital functions, indicating pushes them toward physiological limit. Consequently, increases combination with ocean warming deoxygenation may particularly critical upwelling-exposed build Pacific.

Language: Английский

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Shifts in the coral microbiome in response to in situ experimental deoxygenation

Applied and Environmental Microbiology, Journal Year: 2023, Volume and Issue: 89(11)

Published: Nov. 2, 2023

Marine hypoxia is a threat for corals but has remained understudied in tropical regions where coral reefs are abundant. Though microbial symbioses can alleviate the effects of ecological stress, we do not yet understand taxonomic or functional response microbiome to hypoxia. In this study, experimentally lowered oxygen levels around Siderastrea siderea and Agaricia lamarcki colonies situ observe changes deoxygenation. Our results show that triggers stochastic change overall, with some bacterial families changing deterministically after just 48 hours exposure. These represent an increase anaerobic opportunistic taxa microbiomes both species. Thus, marine deoxygenation destabilizes increases opportunism. This work provides novel fundamental knowledge during may provide insight into holobiont function stress.

Language: Английский

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Cellular adaptations leading to coral fragment attachment on artificial substrates in Acropora millepora (Am-CAM)

Scientific Reports, Journal Year: 2022, Volume and Issue: 12(1)

Published: Nov. 1, 2022

Reproductive propagation by asexual fragmentation in the reef-building coral Acropora millepora depends on (1) successful attachment to reef substrate through modification of soft tissues and (2) a permanent bond with skeletal encrustation. Despite decades research examining corals, initial response, cellular reorganisation, development leading fragment via newly formed skeleton has not been documented its entirety. Here, we establish first "coral model" for this species ("Am-CAM") developing novel methods that allow correlation fluorescence electron microscopy image data vivo microscopic time-lapse imagery. This multi-scale imaging approach identified three distinct phases involved propagation: contact response when substrate, followed stabilisation anchoring tissue, (3) formation "lappet-like appendage" structure bonding tissue encrustation onset calcification. In Am-CAM, provide new biological insights can enable researchers, managers restoration practitioners begin evaluating effectiveness, which is needed optimise species-substrate compatibility achieve effective outplanting.

Language: Английский

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Paired metabolomics and volatilomics provides insight into transient high light stress response mechanisms of the coral Montipora mollis

Metabolomics, Journal Year: 2024, Volume and Issue: 20(4)

Published: June 17, 2024

The coral holobiont is underpinned by complex metabolic exchanges between different symbiotic partners, which are impacted environmental stressors. chemical diversity of the compounds produced high and includes primary secondary metabolites, as well volatiles. However, metabolites volatiles have only been characterised in isolation so far. Here, we applied a paired metabolomic-volatilomic approach to characterise holistically response under stress. Montipora mollis fragments were subjected high-light stress (8-fold higher than controls) for 30 min. Photosystem II (PSII) photochemical efficiency values 7-fold control versus treatment corals immediately following exposure, but returned pre-stress levels after min recovery. Under stress, identified an increase carbohydrates (> 5-fold arabinose fructose) saturated fatty acids (7-fold myristic oleic acid), together with decrease acid derivatives both (e.g., 80% oleamide nonanal), other antioxidants (~ 85% sorbitol galactitol). These changes suggest short-term light induces oxidative Correlation analysis positive links sorbitol, galactitol, six 11 volatiles, four these previously antioxidants. This suggests that 19 may be related share similar functions. Taken together, our findings demonstrate how metabolomics-volatilomics illuminate broader shifts occurring identify linkages uncharacterised putatively determine their

Language: Английский

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