Marine habitat-forming species provide crucial ecosystem functions and services worldwide. Still, the individual and combined long-term effects of ocean acidification and warming on bryozoan populations, structures, and microbiomes remain unexplored. Here, we investigate the skeletal properties, microbiome shifts, and population trends of two bryozoan species living inside and outside a volcanic CO2 vent, a natural analog to future ocean acidification conditions. We show that bryozoans can acclimatize to acidification by adjusting skeletal properties and maintaining stable microbiomes. However, we document a decrease in microbial genera playing essential functions under acidified conditions. Moreover, we show that ocean acidification exacerbates bryozoan cover loss and mortality caused by ocean warming. The observed shifts in the microbiome and cover suggest that, despite their morphological plasticity, bryozoan species will be heavily impacted by future ocean conditions, posing a threat to many benthic ecosystems in which they play a pivotal role.
Continue reading ‘Interactive effects of ocean acidification and warming disrupt calcification and microbiome composition in bryozoans’Posts Tagged 'adaptation'
Interactive effects of ocean acidification and warming disrupt calcification and microbiome composition in bryozoans
Published 12 August 2025 Science ClosedTags: abundance, adaptation, biological response, BRcommunity, bryozoa, community composition, communitymodeling, field, Mediterranean, modeling, molecular biology, morphology, mortality, otherprocess, prokaryotes, vents
Identification, characterization, and expression analysis reveal regulatory roles of MCM genes in Patinopecten yessoensis under low-pH stress
Published 12 August 2025 Science ClosedTags: adaptation, biological response, laboratory, molecular biology, mollusks, North Pacific, otherprocess, reproduction
Highlights
- Nine MCM genes are systematically identified from Patinopecten yessoensis genome.
- PyMCMs are widely expressed during development and adult tissues, especially PyMCM6.
- PyMCM5 is particularly sensitive to low pH stress, whereas PyMCM8 and PyMCM9 are not.
- Scallops reduce DNA replication but maintain DNA repair in response to low-pH stress.
Abstract
The Yesso scallop (Patinopecten yessoensis), an ecomically important bivalve species, exhibits high susceptibility to ocean acidification. The growth retardation induced by low-pH stress poses a significant challenge for Yesso scallop aquaculture. However, the molecular mechanisms underlying this phenomenon are not well understood. Considering the pivotal role of cell proliferation in organism growth, we investigated the minichromosome maintenance (MCM) family in P. yessoensis, which are key regulators of DNA replication initiation and cell cycle regulation. In this study, we identified nine MCM genes (PyMCM2–10) in the P. yessoensis genome. These PyMCMs exhibit highly conserved sequence characteristics and typical MCM domains. Phylogenetic analysis showed that PyMCMs cluster into nine distinct clades, underscoring their strong evolutionary conservation across species homologs. Spatiotemporal expression profiling demonstrated widespread expressions of PyMCMs throughout all developmental stages and adult tissues, with particularly high levels in vigorous cell proliferation (e.g., up to 318 TPM in multicell stage and up to 202 TPM in gonad tissue). Notably, PyMCM6 exhibited consistently high expression across development and across tissues (> 44 TPM), suggesting a key regulatory role in both development and tissue maintenance. Under low-pH stress, the expressions of PyMCMs were downregulated to varying degrees, with PyMCM5 showing the most significant reduction (|log2FC| up to 3.5), while PyMCM8 and PyMCM9 remained relatively stable. This pattern suggests a strategic response that scallops reduce DNA replication capacity (mediated by PyMCM2–7) but potentially maintain DNA repair functions (associated with PyMCM8/9 stability) to mitigate damage induced by low-pH, potentially explaining the intrinsic inhibition of cell proliferation. Quantitative real-time PCR and in situ hybridization further confirmed that low-pH stress inhibits PyMCMs expressions (p < 0.05), with the effect amplified as pH decreases. Collectively, these findings enhance our understanding of PyMCMs in regulating bivalve growth retardation under low-pH stress and provide valuable insights into the mechanisms of environmental adaptation in bivalves.
Continue reading ‘Identification, characterization, and expression analysis reveal regulatory roles of MCM genes in Patinopecten yessoensis under low-pH stress’Antarctic fishes in a changing climate: a comparative approach to predicting species-specific futures
Published 12 August 2025 Science ClosedTags: adaptation, Antarctic, biological response, fish, multiple factors, otherprocess, performance, temperature
The polar regions are experiencing climate change at the fastest rates on Earth and serve as bellwethers for the profound threats facing species, ecosystems, and physical processes worldwide due to uncurbed anthropogenic greenhouse gas emissions. My dissertation research focuses on early life stages of Antarctic fishes, which are thought to be particularly vulnerable to climate change due to their unique evolutionary history and specialization to their stenothermal habitat. I used a comparative framework, examining four closely related species in the Nototheniidae family – Trematomus bernacchii, Trematomus pennellii, Trematomus nicolai, and Pagothenia borchgrevinki – to understand how subtle interspecific variation in traits may impact species-specific performance under projected future ocean conditions. I first measured basal characteristics across the four species, as very little is known about Antarctic fishes at young life stages, focusing on metabolic traits and the exploration-avoidance axis of behavior, two key dimensions of species fitness and drivers of niche differentiation. While basal metabolic demands appeared relatively conserved across species at the juvenile life stage, I found divergent behavioral strategies that could be a critical driver of niche differentiation in Antarctic fish assemblages. T. bernacchii and T. pennellii showed risk-prone behavior, T. nicolai showed avoidant behavior, and P. borchgrevinki showed cautious exploratory behavior. I also observed a potentially conserved freezing strategy in response to novelty, which, when paired with in situ observations, indicates that freezing may be an important predator avoidance strategy in these fishes. I then focused on the two ‘risky’ species – Trematomus bernacchii and Trematomus pennellii – to explore how acclimation to projected future ocean warming and ocean acidification conditions may impact their risk-prone behavior. While acclimation to warming and elevated pCO₂ affected behavior in both species, the effect sizes of pCO₂ were small, and warming was the driving force behind behavioral modifications. In both species, fishes acclimated to ocean warming conditions demonstrated reduced exploratory activity and showed indications of neophilia. These responses amplified over time, and T. pennellii demonstrated a stronger response (i.e., effect sizes) in both behaviors. Consistent with previous physiological and behavioral studies, while limited, our results support the inference that T. pennellii have a particularly risk-prone strategy when faced with novelty that is amplified when acclimated to warming. My final chapter proposes a novel ‘ice reef’ framework and emphasizes how three-dimensional ice habitat formed by platelet, anchor, and brinicle ice may function as critical nursery and refugia habitats for young polar fishes. Drawing on in situ observations and the literature, I discuss the recurring behavioral, physiological, and morphological features across a diversity of polar fishes, suggesting ice-associated and ice-obligate life history strategies may be much more widespread than previously acknowledged. As climate change rapidly alters ice phenology and stability, the loss of ice reefs could jeopardize fish recruitment, community resilience, and key ecosystem services. This perspective underscores the urgent need to study ice reefs before they disappear altogether.
Continue reading ‘Antarctic fishes in a changing climate: a comparative approach to predicting species-specific futures’Adaptive phenotypic evolution of Skeletonema costatum to ocean acidification and warming with trade-offs from a multi-year outdoor experiment
Published 11 August 2025 Science ClosedTags: adaptation, biological response, growth, laboratory, mesocosms, multiple factors, otherprocess, photosynthesis, physiology, phytoplankton, temperature
Human-induced climate change is increasing variability in marine environments, significantly affecting marine organisms and ecosystems. While marine diatoms can adapt to ocean acidification and warming in stable laboratory settings, their responses to long-term environmental changes under natural variability remain unclear. To investigate this, we cultivated Skeletonema costatum in outdoor semi-continuous cultures for over 3 years, exposing them to fluctuating natural light and temperature that tracked the in situ sea surface temperatures. We simulated current and future ocean conditions through four treatments: ambient CO2 and temperature (LTLC), elevated CO2 (LTHC), elevated temperature (+4°C, HTLC) and combined increases (HTHC). After 1396 days, we assessed populations in two assay environments (20°C, 400 ppm CO2 and 24°C, 1000 ppm CO2) for adaptations in growth rate, pigment composition and photosynthesis. The HTLC-selected group showed the highest growth rates in the HTHC assay environment, while the LTLC-selected group grew fastest in the LTLC assay environment, indicating adaptive evolution. Furthermore, populations selected under elevated conditions exhibited lower fitness in LTLC environments, highlighting a trade-off and underscoring the complexity of evolutionary adaptation in marine diatoms. Understanding these mechanisms is crucial for predicting phytoplankton dynamics and their role in marine ecosystems, especially in response to climate change.
Continue reading ‘Adaptive phenotypic evolution of Skeletonema costatum to ocean acidification and warming with trade-offs from a multi-year outdoor experiment’Epigenetic insights into physiological resilience: multigenerational readouts of CO2-induced seawater acidification effects on fish embryos
Published 5 August 2025 Science ClosedTags: adaptation, biological response, fish, laboratory, molecular biology, morphology, otherprocess, physiology, reproduction
Highlights
- Ocean acidification causes generation-specific developmental and metabolic changes.
- F2 embryos show enhanced resilience through transcriptional recovery mechanisms.
- Hypomethylation of ion transport genes drives adaptive acid-base regulation.
- Epigenetic inheritance facilitates multigenerational acclimation to acidification.
Summary
Anthropogenic CO2 emissions are acidifying oceans, threatening marine organisms during early development. We investigated multigenerational effects of projected 2100 acidification (pH 7.6) on marine medaka (Oryzias melastigma) embryos across three generations using integrated phenotypic, physiological, transcriptomic, and epigenetic analyses. Prolonged acidification altered developmental trajectories, with F2 embryos showing size reductions. Metabolic responses were generation-specific: F0 embryos displayed decreased ammonium excretion, while F1 and F2 maintained stable profiles. Transcriptomic analysis revealed generational changes in neurotransmission, ion regulation, and epigenetic pathways. F2 embryos exhibited attenuated transcriptional perturbations and partial restoration of acid-base homeostasis, suggesting enhanced adaptability. Adaptive gene expression correlated with hypomethylation recovery of ion transport genes AE1a and NHE2 in F2 embryos. Increased hypomethylated AE1a promoter CpG sites in F1 and F2 generations aligned with elevated transcription, indicating epigenetically-driven enhancement. These results demonstrate epigenetic control’s crucial role in multigenerational plasticity and adaptive responses to ocean acidification.
Continue reading ‘Epigenetic insights into physiological resilience: multigenerational readouts of CO2-induced seawater acidification effects on fish embryos’Multi generational acclimation of Scrippsiella trochoidea to ocean warming and acidification
Published 4 August 2025 Science ClosedTags: adaptation, biological response, growth, laboratory, multiple factors, otherprocess, physiology, phytoplankton, temperature
Dinoflagellates, particularly harmful algal bloom (HAB)-forming species, exhibit remarkable resilience to climate change stressors, including ocean warming and acidification. However, their specific acclimation strategies compared to other phytoplankton groups remain poorly understood. This study investigates the multi-generational acclimation mechanisms of Scrippsiella trochoidea under simulated future ocean conditions (25°C, 1000 ppm pCO₂; HTHC) compared to present-day conditions (21°C, 400 ppm pCO₂; LTLC). Over 10 generations, S. trochoidea demonstrated significant physiological and biochemical adjustments, including a 79% increase in growth rate, a 73% rise in cell volume, and notable elevations in macromolecular components such as carbohydrates (38%), lipids (48%), proteins (90%), and chlorophyll (158%). These changes were accompanied by enhanced carbon fixation and nutrient acquisition. During the compensation phase (fifth generation), S. trochoidea exhibited a unique nitrate-phosphate trade-off, redirecting nitrates to nucleic acid biosynthesis and chlorophyll production while utilizing phosphorus storage for phospholipid synthesis. This strategy resulted in increased residual phosphorus and alternative lipid sources, highlighting a distinct acclimation mechanism compared to other phytoplankton groups. These findings underscore the ecological importance of dinoflagellates in shaping biogeochemical cycles under future ocean scenarios. By revealing their unique adaptive strategies, this study provides essential insights into predicting HAB dynamics and mitigating their ecological and economic impacts. Incorporating these results into predictive models will enhance our ability to forecast bloom events and guide effective marine management strategies, such as nutrient runoff control and habitat restoration, in the context of climate change.
Continue reading ‘Multi generational acclimation of Scrippsiella trochoidea to ocean warming and acidification’Complementary genetic and epigenetic changes facilitate rapid adaptation to multiple global change stressors
Published 1 August 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, molecular biology, multiple factors, otherprocess, temperature, zooplankton
Significance
Organisms must adapt or acclimate to survive global change, but how these processes interact and the role of epigenetic variation is unknown. We experimentally evolved the marine copepod Acartia tonsa for 25 generations in global change conditions and measured their genomic, epigenomic, and gene expression responses. We found that both genetic and epigenetic changes contributed to resilience and were inversely related, acting in different regions of the genome. Epigenetic changes were functionally linked to the regulation of stress and transposable elements and correlated with shifts in gene expression. These findings paint a surprising picture of the complementary contributions of both genetic and epigenetic mechanisms to population resilience in global change conditions.
Abstract
To persist under unprecedented rates of global change, populations can adapt or acclimate. However, how these resilience mechanisms interact, particularly the role of epigenetic variation in long-term adaptation, is unknown. To address this gap, we experimentally evolved the foundational marine copepod Acartia tonsa for 25 generations under ocean acidification, warming, and their combination and then measured epigenomic, genomic, and transcriptomic responses. We observed clear and consistent epigenomic and genomic divergence between treatments, with epigenomic divergence concentrated in genes related to stress response and the regulation of transposable elements. However, epigenetic and genetic changes were inversely related and occurred in different regions of the genome; levels of genetic differentiation (FST) were up to 2.5× higher in regions where methylation did not differ between treatments compared to regions with significant methylation changes. This negative relationship between epigenetic and genetic divergence could be driven by local inhibition of one another or distinct functional targets of selection. Finally, epigenetic divergence was positively, though weakly, associated with gene expression divergence, suggesting that epigenetic changes may facilitate phenotypic change. Taken together, these results suggest that unique, complementary genetic and epigenetic mechanisms promote resilience to global change.
Continue reading ‘Complementary genetic and epigenetic changes facilitate rapid adaptation to multiple global change stressors’Impacts of multiple coastal stressors across life-history stages in the eastern oyster
Published 31 July 2025 Science ClosedTags: adaptation, biological response, laboratory, molecular biology, mollusks, multiple factors, otherprocess, oxygen, reproduction
Urbanized estuaries are characterized as a complex of biotic and abiotic stressors, which currently challenge marine life and are expected to intensify and become increasingly unpredictable under the ongoing impacts of climate change. The persistence of coastal species that inhabit these stressful environments will ultimately depend on their ability to adapt. Many of these species have complex life cycles, featuring distinct morphological and physiological developmental stages that can exhibit unique responses to environmental pressures. However, since all stages share the same genome, selective pressures acting on one stage can have cascading effects throughout the life cycle. The larval stage, being particularly sensitive to environmental stressors and often the only free-moving stage, plays a crucial role in gene flow across populations. Consequently, selection during this stage can set the trajectory for the entire life cycle and significantly influence the adaptive structure of populations. This dissertation explores the impacts of multiple environmental stressors across the life-history stages of the eastern oyster (Crassostrea virginica). In Chapter 1, we integrated genomic information about larval stressor response into a seascape genomics framework, using adult oysters sampled from various localities with differing environmental profiles in Narragansett Bay, Rhode Island. We identified environmentally driven signatures of local adaptation corresponding to different genomic regions, even amidst high gene flow. In loci putatively under selection in larvae exposed to coastal stressors, we found stressor-specific associations with environmental conditions that aligned with adult candidate loci, highlighting the critical role of the larval stage in shaping population adaptive divergence. In Chapter 2, we exposed genetically diverse pools of larval oysters to diurnal fluctuating acidification and hypoxia for most of their development. Genomic analysis of samples taken before and after exposure revealed substantial shifts in allele frequencies at loci putatively under selection, suggesting a potential for rapid adaptation to future environmental conditions. Chapter 3 extended this work by exposing oysters to these stressors from the pediveliger stage, through settlement, and into early juvenile development. Genomic analysis from the larval and settlement exposure periods revealed both unique and shared signatures of selection across the early developmental stages. While the juvenile stage was more tolerant to the stressor conditions, we found that stressor exposure through the pediveliger larval and settlement stages had short-term carryover effects on juvenile performance. These findings demonstrate the complex connection of evolutionary responses across the full life cycle. While early developmental stages are sensitive to coastal stressors, our analysis reveals adaptive responses that highlight the resilience of this species. Specifically, these early life-stage responses can influence later developmental stages, shaping the species’ overall adaptive capacity and impacting population structure dynamics. Consequently, understanding these dynamics is crucial for predicting how population structure and adaptive divergence will evolve in response to intensifying coastal stressors.
Continue reading ‘Impacts of multiple coastal stressors across life-history stages in the eastern oyster’Potential for regional resilience to ocean warming and acidification extremes: projected vulnerability under contrasting pathways and thresholds
Published 30 July 2025 Science ClosedTags: adaptation, biogeochemistry, chemistry, globalmodeling, mitigation, modeling, otherprocess
We analyze the frequency and amplitude of projected warming and ocean acidification extremes under high CO2 and strongly mitigating scenarios. We find interpretational differences in projections arising from methodological choices associated with specification of stressor thresholds. Use of absolute versus distribution-based thresholds, and, in the distribution-based case, the inclusion or exclusion of seasonal variability, can lead to very different regional patterns in projected stress. The choice of fixed versus adaptive baseline, for example, determines whether future stress frequency in the low-CO2 scenario most closely resembles that in the high-emissions scenario or historical period. We find that mitigation through emissions reductions, in combination with representation of rates of adaptation that are realistic for some marine organisms, has the potential to dampen end of century threshold exceedance to frequencies of occurrence closer to the recent historical period than to the high-emissions scenario.
Continue reading ‘Potential for regional resilience to ocean warming and acidification extremes: projected vulnerability under contrasting pathways and thresholds’Adaptive responses of large yellow croaker Larimichthys crocea to ocean acidification: integrative analysis of gill and kidney transcriptomics and antioxidant enzyme activities
Published 21 July 2025 Science ClosedTags: adaptation, biological response, fish, laboratory, molecular biology, morphology, North Pacific, otherprocess, physiology
Anthropogenic acidification is a long-term challenge to marine ecosystems. Though coastal acidification is intensifying, the large yellow croaker (Larimichthys crocea) exhibits good adaptability to pH fluctuations, the underlying mechanisms of which remain poorly understood. This study investigated the morphology, antioxidant enzyme activity, and gene expression of L. crocea under varying acidification conditions (pH 8.1 (H group), 7.8 (M group), and 7.4 (L group)). Water pH fluctuations were also monitored to explore the physiological responses and potential adaptive molecular mechanisms of L. crocea under various acidified environments. The results indicated that the water pH decreased in the H group, significantly increased in the L group (p < 0.05), and remained stable in the M group during the experiment. The lowest MDA content and the highest antioxidant enzyme activities (CAT, SOD, GSH-Px) were observed in L. crocea at pH 7.8, suggesting pH 7.8 was optimal for L. crocea. Transcriptomic analysis revealed distinct gene expression patterns between the gills and kidneys under acidification stress. Differentially expressed genes (DEGs) in the gills were primarily observed between the M and L groups (62.3%), whereas in the kidneys, the majority of DEGs were observed between the M and H groups (43.2%). These findings suggested that the gills play a critical role in adapting to low pH in L. crocea, while the kidneys were more responsive to high pH. Enrichment analysis identified critical pathways, including vasopressin-regulated water reabsorption, mineral reabsorption, and aldosterone-regulated sodium reabsorption, which are associated with water and ion metabolism. These pathways play a pivotal role in the acid–base homeostasis and metabolism of L. crocea. These results provide insights into the adaptive mechanisms of L. crocea to acidified environments, with implications for aquaculture management and future ocean acidification adaptation.
Continue reading ‘Adaptive responses of large yellow croaker Larimichthys crocea to ocean acidification: integrative analysis of gill and kidney transcriptomics and antioxidant enzyme activities’Adaptation strategy of the planula strobilation in moon jelly, Aurelia coerulea to acidic environments in terms of statolith formation
Published 21 July 2025 Science ClosedTags: adaptation, biological response, cnidaria, laboratory, morphology, North Pacific, otherprocess
Simple Summary
Ocean acidification poses a significant threat to marine invertebrates with calcium-based structures. This study investigated the effects of low pH on two types of strobilation in Aurelia coerulea: polyp-strobilation (conventional asexual reproduction from polyps) and planula-strobilation (direct development from planulae). Experiments were conducted under pH 6.8, 7.8, and 8.1 conditions to observe morphological changes and statolith formation in ephyrae. Under the pH 6.8 condition, polyp-strobilation failed to produce normal ephyrae, while planula-strobilation succeeded in releasing morphologically normal ephyrae, albeit without statoliths. Under the pH 7.8 condition, both strobilation types produced ephyrae with altered statolith morphology. These statoliths were smaller in size but more numerous than those formed at pH 8.1 as normal pH, suggesting a compensatory mechanism that maintains total statolith mass and potentially preserves function. Planula-strobilated ephyrae had fewer but larger, needle-shaped statoliths, suggesting rapid statolith development. These findings suggest that planula-strobilation functions as a stress-adaptive reproductive strategy, producing the minimum necessary morphology and internal structures to ensure survival in a changing environment. The ability of Aurelia coerulea to adjust reproductive strategy and developmental traits under acidified conditions may contribute to its ecological success and persistence under future climate change scenarios.
Abstract
Ocean acidification, caused by increased atmospheric CO2, threatens marine organisms that depend on calcium-based structures such as jellyfish statoliths. This study investigated the effects of low pH on the morphology and statolith formation of ephyrae in Aurelia coerulea, comparing two developmental pathways to form ephyra: polyp-strobilation and planula-strobilation. Under the pH 6.8 condition, polyps failed to produce viable ephyrae, whereas planula-strobilation succeeded in releasing ephyrae with normal morphology, though statoliths were absent. Under the pH 7.8 condition, both strobilation types produced normal-shaped ephyrae with reduced statolith size but increased statolith number compared with the control (pH 8.1), suggesting a compensatory response to acidification. Statolith morphology differed between pathways: planula-strobilated ephyrae had needle-shaped statoliths with high aspect ratios, indicating a rapid, early-stage crystallization process. Despite their minimal body size and statolith development, planula-strobilated ephyrae maintained the functional mass of statoliths necessary for survival. This rapid, morphologically minimized development suggests that planula-strobilation is an adaptive reproductive strategy in response to environmental stress. Our findings suggest that A. coerulea possesses a flexible life history strategy that may facilitate its resilience to ongoing ocean acidification scenarios.
Continue reading ‘Adaptation strategy of the planula strobilation in moon jelly, Aurelia coerulea to acidic environments in terms of statolith formation’Stage-dependent life-history, physiological, and behavioral responses to low pH in an estuarine crab
Published 18 July 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, mortality, otherprocess, performance, physiology, reproduction, South Atlantic
Highlights
- We assessed the effects of low pH on larval stages of the crab Neohelice granulata.
- Low pH affects intermolt period, mortality, and oxygen consumption.
- Low pH also impacts swimming velocity and distance traveled.
- Marine larval stages were more adversely affected than the exported (first) larval stage.
Abstract
Early stages of marine invertebrates are vulnerable to ocean acidification. We investigated low pH effects on larval stages of the crab Neohelice granulata. We hypothesized that Zoea I, adapted to fluctuating environments, would show greater resilience than Zoea II and III, which develop in stable nearshore areas. We assessed pH 8 -control-, pH 7.5, and pH 6.9 effects on intermolt duration, mortality, oxygen consumption, and swimming behavior. Zoea I tolerated low pH with no changes in development or mortality, though oxygen consumption decreased at pH 6.9. In contrast, Zoea II and III showed delayed development, higher mortality, and reduced oxygen consumption at pH 6.9. While Zoea I showed no changes in swimming, Zoea II and III exhibited reduced swimming velocity and distance traveled under acidified conditions. These findings show that Zoea II and III are more sensitive to low pH, while Zoea I is more resilient.
Continue reading ‘Stage-dependent life-history, physiological, and behavioral responses to low pH in an estuarine crab’Energetic adaptations of bivalves under environmental stress: a comprehensive review on bioenergetics and aquaculture sustainability
Published 18 July 2025 Science ClosedTags: adaptation, biological response, fisheries, mollusks, otherprocess, physiology, review
Bioenergetics, or scope for growth (SFG), is a model used to assess the health and adaptability of mollusks to external factors. It achieves this by converting physiological responses, such as clearance rate (CR), respiration rate (RR), excretion rate (ER), absorption efficiency (AE), and oxygen–nitrogen ratio (O:N ratio), into energy equivalents. This biomarker reflects the energy available for growth and reproduction, indicating an organism’s potential to adapt to environmental change and revealing the energetics behind growth. It has been a significant focus in marine ecology, biology, and aquaculture of mollusks. To understand the effects of various factors on the bioenergetics of bivalves, the effects of temperature, ocean acidification (OA), salinity, dissolved oxygen (DO), trace elements (e.g., copper (Cu), zinc (Zn), cadmium (Cd)), micro/nanoparticles (MPs/NPs), harmful algae, and other factors on the physiology and energy budget of bivalves were summarized and analyszed in this paper. We found that some influencing factors (e.g., OA, trace elements, and harmful algae) serve as selective pressures that make bivalves adapt to environmental changes, and the impacts of various stressors on the SFG in bivalves are diverse. However, under hypoxia and salinity changes, exceeding bivalve tolerance can lead to metabolic disorders and reduced SFG, impacting populations and aquaculture. At the same times, we analyzed WOS literature from 1980 to 2023 using VOS-viewer software to assess how climate change and pollutants affect bivalve energy assimilation and consumption, offering insights for bivalve biology and aquaculture research.
Continue reading ‘Energetic adaptations of bivalves under environmental stress: a comprehensive review on bioenergetics and aquaculture sustainability’Shifts in coral reef holobiont communities in the high-CO2 marine environment of Iōtorishima Island
Published 15 July 2025 Science ClosedTags: adaptation, biological response, BRcommunity, community composition, corals, field, molecular biology, North Pacific, otherprocess, phytoplankton, prokaryotes, vents
Ocean acidification (OA), driven by rising atmospheric CO2, presents a serious threat to marine biodiversity, especially within coral reef ecosystems. Natural analogue sites, such as the high-pCO2 seep at Iōtorishima Island in Japan, offer insights into future conditions. This study investigated the holobiont communities of Symbiodiniaceae and bacteria in the zoantharian Palythoa tuberculosa at Iōtorishima and compared them to specimens from control sites in Okinawa and Hawaiʻi. Using amplicon sequencing of the dinoflagellate internal transcribed spacer 2 (ITS2) region of ribosomal DNA and microbial 16S rRNA gene, we detected significant shifts in both Symbiodiniaceae and bacterial communities under high-pCO2 conditions at Iōtorishima. Specifically, P. tuberculosa at the seep site had reduced Symbiodiniaceae diversity, predominatly featuring Cladocopium C1 and C3 types. Additionally, its bacterial communities showed lower richness with distinct taxonomic profiles, including increased levels of Mollicutes and Vibrio spp. These results highlight the potentially adverse effects of OA on hexacoral holobionts and emphasize the need for detailed, high-resolution studies across various holobiont species and geographic locations. The shifts observed specifically in Symbiodiniaceae and bacterial communities at the Iōtorishima seep suggest that holobionts may exhibit plasticity in response to environmental stress, which has implications for resilience and adaptation of zoantharians and other reef organisms amid climate change. This research provides crucial baseline data for predicting future coral reef compositions in an OA-affected world.
Continue reading ‘Shifts in coral reef holobiont communities in the high-CO2 marine environment of Iōtorishima Island’Coral calcification mechanisms across a natural environmental mosaic in Hawai’i
Published 9 July 2025 Science ClosedTags: adaptation, biological response, chemistry, corals, field, North Pacific, otherprocess, physiology
Coral calcification is key to coral reef growth and function but may be compromised under increasing global and local stressors. Corals modify the carbonate chemistry of their calcifying fluid to facilitate calcification, but little is known about how these mechanisms vary across the substantial differences in reef seawater conditions that can occur over as little as a few kilometers. Here, we used boron-based geochemical proxies (δ11B, B/Ca) to investigate how three common Hawaiian coral species (Montipora capitata, Porites compressa, Porites lobata) regulate the carbonate chemistry of the calcifying fluid along a natural environmental mosaic of seawater carbonate chemistry and significant wave height. We found that calcification mechanisms were governed by complex species and site interactions: while all species generally differed from each other in their calcifying fluid chemistry, they also responded differently to site-specific environmental conditions. These results highlight that there are varying degrees of calcification mechanism plasticity in response to changing environmental conditions. Furthermore, species-specific patterns of pH upregulation inside the calcifying fluid were good predictors of calcification responses to ocean acidification and warming in at least two of the three species, with M. capitata being a clear winner under future ocean conditions. Our findings provide important insights into how corals calcify across a natural environmental mosaic and highlight the differential potential for an adaptive capacity in calcification mechanisms in the face of intensifying climate change.
Continue reading ‘Coral calcification mechanisms across a natural environmental mosaic in Hawai’i’Nutritional status and shell properties of the scallop Argopecten purpuratus are sensitive to intense upwelling events
Published 8 July 2025 Science ClosedTags: adaptation, biological response, field, mollusks, morphology, multiple factors, otherprocess, oxygen, physiology, South Pacific, temperature
Highlights
- The scallop Argopecten purpuratus cope with permanent environmental fluctuations.
- Upwelling intensity and duration affect its physiological perfomance.
- Shell organic matrix was adversely affected by intense upwelling events.
- The nutritional status of the A. purpuratus is modulated by upwelling intensity.
- A. purpuratus seems to be partially adapted to colder, low pH and hypoxic conditions.
Abstract
Changes in environmental conditions can be particularly stressful for marine biota. However, marine organisms possess a variety of biological mechanisms (e.g., expression of stress proteins, down or up metabolic regulation, among others) that enable them to adapt to such conditions. This will ultimately determine their resilience and adaptive capacity to the natural environmental fluctuations occurring in their habitats, but also to future climate-driven shifts. In Chile, the scallop Argopecten purpuratus inhabits regions under permanent upwelling conditions causing, at different temporal and spatial scales, cooling, low pH and hypoxic conditions of diverse magnitude. In one-year field experiment, we observed that A. purpuratus was, in some occasions, adversely affected by intense upwelling events during the spring season, when the most intense upwelling events were observed, and thus the lowest temperatures, pH and oxygen levels were registered. These effects were more evident in some shell properties, such as the shell organic matrix, a key component of the biomineralization process. Also, no impacts or positive responses (i.e., up-regulation) were observed on parameters associated to their nutritional status (i.e., carbohydrate and protein muscle content), and periostracum thickness suggesting the presence of physiological trade-offs, but also adaptive mechanisms serving to cope with stressful environmental conditions. Ultimately, our findings also raise concerns about the potential consequences of intensified upwelling due to climate change, particularly for the aquaculture sector that relies on this species, since the majority of impacts were observed in individuals of sizes considered attractive to the market.
Continue reading ‘Nutritional status and shell properties of the scallop Argopecten purpuratus are sensitive to intense upwelling events’Phenotypic plasticity in Mediterranean gorgonians Eunicella singularis and Paramuricea clavata at high temperature and low pH
Published 2 July 2025 Science ClosedTags: adaptation, biological response, corals, laboratory, Mediterranean, molecular biology, multiple factors, otherprocess, performance, physiology, temperature
Highlights
- The oxygen consumption of the gorgonian corals increased at high temperatures.
- Energy reserves were not affected by high temperature, low pH or their interaction.
- The global DNA methylation in Eunicella singularis was not affected by high temperature, low pH, or their combination.
- Global DNA methylation in Paramuricea clavata decreased under high temperature and low pH.
- High temperature alone caused more DEGs in E. singularis than low pH or combined treatment.
Abstract
The Mediterranean gorgonian octocorals are threatened by acidification, warming and marine heat waves. Phenotypic plasticity is critical for slow-growing gorgonians, as adaptation through natural selection might not be fast enough to cope with rapid environmental changes. DNA methylation (DNAm) is a type of (trans)generational phenotypic plasticity mechanism that may help slow-growing corals better withstand the effects of environmental changes by adjusting gene expression. This study aimed to assess the physiological responses and epigenetic modifications associated with phenotypic plasticity in the Mediterranean gorgonians Eunicella singularis and Paramuricea clavata exposed to warming (+4 °C), acidification (−0.35 pHT units) and their combination over two weeks. In addition, RNA-Seq-based differential gene expression analysis was performed for E. singularis.
High temperature, low pH and their combination did not cause tissue death or necrosis in the corals. Polyp activity in E. singularis increased at high temperatures. Warming increased oxygen consumption in both species. Energy reserves (protein, lipid, carbohydrate contents) were not affected by temperature, pH or their interaction in either species. The global DNA methylation (gDNAm) rate was ten times higher in P. clavata than in E. singularis. There was no effect of temperature, pH or their interaction on gDNAm in E. singularis. gDNAm in P. clavata decreased at high temperatures and low pH. Differential gene expression analysis indicated that high temperature induced the most extensive transcriptional changes in E. singularis, while low pH alone had the least impact. The combined stress of high temperature and low pH also led to notable up- and downregulation of gene expression. Heat stress in E. singularis caused widespread downregulation of transcription factors (TFs), particularly those in the zf-C2H2, AP-2, and HMG families. Conversely, the IRF, RFX, P53, and NRF1 families were upregulated, highlighting the complex transcriptional response to thermal stress. Overall, these physiological, transcriptomic and epigenetic alterations have the potential to negatively impact the fitness of these emblematic species and their associated ecosystems.
Continue reading ‘Phenotypic plasticity in Mediterranean gorgonians Eunicella singularis and Paramuricea clavata at high temperature and low pH’Non-additive phospholipidomic responses to ocean warming and acidification drive intraspecific variation in cell membrane vulnerability in a marine ectotherm
Published 1 July 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, multiple factors, North Atlantic, otherprocess, physiology, temperature
Highlights
- Shrimp show non-additive phospholipidome responses to combined OW and OA.
- Synergistic and antagonistic responses are origin- and scenario-dependent.
- Physiological shifts emerge when OA occurs near shrimp’s thermal limits.
- Shrimp show potential local adaptation/acclimatisation of cell membrane phenotypes.
- Shrimp cell membrane vulnerability to combined OW and OA is origin-dependent.
Abstract
The lipidome is fundamental to the good functioning of cells and organisms. However, its role in species acclimatisation and adaptation to global changes remains overlooked. Investigating intraspecific variation in lipidome responses to combined global change drivers is therefore paramount to predict species’ vulnerability in future oceans. Here, we profiled the phospholipidome of the Northern shrimp, Pandalus borealis, from four different origins in the Northwest Atlantic, within an orthogonal design of ocean warming (OW) and acidification (OA) scenarios. We report complex origin-dependent non-additive responses under combined global changes. Shrimp display a high degree of intraspecific variation with distinct profiles of synergism, antagonism or temperature-driven phospholipidome responses when OA is superimposed on OW. Shrimp from the southernmost origin are only sensitive to OW, whilst those from the other three origins respond to combined OW and OA. These patterns involve changes in cellular membranes’ unsaturation, fluidity, curvature and thickness, underlying differential intraspecific cellular vulnerability to global changes. The isolated effects of OA are subtler, visible only in shrimp from the St. Lawrence Estuary (SLE). Shrimp from SLE also show the most pronounced phospholipidome remodelling, allowing them to acclimate to combined OW and OA. Whilst SLE shrimp seem most sensitive to global changes, those from the northernmost origins (Newfoundland and Esquiman Channel) display the greatest cellular vulnerability under combined OW and OA. Our findings evidence the highly complex interplay of OW and OA in remodelling marine ectotherms’ phospholipidomes, with direct implications for prioritising conservation efforts on populations most vulnerable to global changes.
Continue reading ‘Non-additive phospholipidomic responses to ocean warming and acidification drive intraspecific variation in cell membrane vulnerability in a marine ectotherm’Short and long-term exposure to ocean acidification in limpets from the Castello Aragonese vent systems (Ischia Island, Italy)
Published 12 June 2025 Science ClosedTags: adaptation, biological response, field, Mediterranean, mollusks, morphology, otherprocess, physiology, vents
Highlights
- First investigation limpet populations collected from the naturally acidified site.
- Increased dimension and energy endpoints in Patella caerulea from very low pH (<7.4).
- Induction of antioxidant systems and neurotoxicity in Patella rustica exposed to OA.
- Transplant of Patella caerulea activated oxidative stress and neurotoxicity endpoints.
Abstract
Ocean acidification (OA) is reported to entail a detrimental impact on calcifying organisms. Nevertheless, patellid limpets – P. caerulea, P. rustica, and P. ulyssiponensis – are able to persist in extremely low pH conditions inside the Castello Aragonese CO2 vent systems (Ischia Island), suggesting that they may have developed tolerance to OA, through plasticity and/or adaptive mechanisms. The aim of this study is to evaluate the long-term strategies adopted by limpets that spent their entire life cycle in naturally acidified conditions and the short-term ones induced by a 30-day in situ transplant experiment.
Regarding native limpet populations, P. caerulea exhibited increasing size and higher energy resources in the extremely acidified site, potentially related to different food availability or to reduction in competition and/or predatory pressure; furthermore, no effects on oxidative stress, biomineralization and neurotoxicity occurred. Similarly, P. ulyssiponensis didn’t exhibit any significant effects among different pH conditions regarding biochemical endpoints. Conversely, P. rustica displayed a significant modulation of almost all biochemical parameters, possibly due to its different position on the rocky shore. The short-term exposure of P. caerulea produced a decrease in protein content and an increase in glycogen content in the extreme acidified site, with an induction of superoxide dismutase and glutathione-S-transferases activities in the intermediate pH site.
Overall, our study revealed that different species of the same genus may have developed distinct responses to OA and suggested different mechanisms to cope with short and long-term exposure to low pH conditions.
Continue reading ‘Short and long-term exposure to ocean acidification in limpets from the Castello Aragonese vent systems (Ischia Island, Italy)’Population and maternal variation in the sensitivity of Dungeness crab Metacarcinus magister zoeae to elevated CO2
Published 10 June 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, morphology, mortality, North Pacific, otherprocess, reproduction
The response of marine organisms to ocean acidification depends on their adaptive capacity, which can be partially understood by evaluating the amount of existing variability in CO2 sensitivity within a species. The process of local adaptation is a mechanism that can drive variability in CO2 sensitivity. In this study, we measured the survival and molt rate of Dungeness crab Metacarcinus magister zoeae that were produced by gravid crabs collected from 3 locations in waters off of Washington State, USA, and reared in a common laboratory in ambient, medium, and high CO2 treatments. The 3 locations from which crabs were collected have different carbonate chemistry dynamics, and Dungeness crabs in these locations are to some extent genetically distinct. We hypothesized that these conditions may favor local adaptation. We did not find evidence of local adaptation, but did see different levels of CO2 sensitivity associated with the mother. This variation in CO2 sensitivity suggests an adaptive capacity that is likely to influence Dungeness crab response to future acidification.
Continue reading ‘Population and maternal variation in the sensitivity of Dungeness crab Metacarcinus magister zoeae to elevated CO2’
