Understanding how marine species tolerate acidified conditions is critical for predicting biological responses to ocean change. A recent one-year experiment (Long 2026) found that juvenile snow crab (Chionoecetes opilio) maintain growth and molting under acidification (pH 7.8, 7.5), and survival begins to decline only after ∼250 days under severe acidification (pH 7.5). In this companion study, we characterized whole-transcriptome responses after 8 hours and 88 days of exposure to identify molecular mechanisms underlying short-term tolerance and chronic effects of ocean acidification. The immediate transcriptional response involved strong activation of genes associated with mitochondrial metabolism and biogenesis, protein homeostasis, cuticle maintenance, and immune modulation, processes shared between moderate and severe treatments but of greater magnitude under severe acidification. After 88 days, expression patterns diverged, revealing sustained upregulation of stress- and damage-mitigation pathways in the severe treatment (pH 7.5) compared to the moderate treatment (pH 7.8). These findings indicate that crabs in severe acidification are likely to experience chronic OA stress that precedes outward physiological effects, and provides a mechanistic basis for delayed mortality. We further highlight potential early indicators of chronic acidification stress in snow crab, among which a gene likely coding for carbonic anhydrase 7 (CA7, GWK47_031192) appears to be the most promising biomarker.
Continue reading ‘Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab’Posts Tagged 'crustaceans'
Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab
Published 20 February 2026 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, molecular biology, morphology, mortality, North Pacific, otherprocess, physiology, reproduction
Untargeted mass spectrometry to investigate ocean acidification in Cancer borealis using optimized metabolite extraction methods
Published 5 February 2026 Science ClosedTags: biological response, crustaceans, laboratory, methods, physiology
Ocean acidification (OA) refers to the ongoing decline in ocean pH caused by the cascading effects of increased atmospheric CO2, which has significant negative impacts on various marine organisms, particularly crustaceans with calcified shells. However, research on the metabolic responses of crustaceans remains limited. In this study, we performed untargeted metabolomics on hemolymph samples from Cancer borealis (Jonah crab), a crustacean species well known for its tolerance to temperature and pH changes, to investigate its metabolic responses to OA. Two extraction methods—isopropanol (IPA) and acidified methanol (AcMeOH)—were employed to capture a broad range of metabolites and small peptides. Both methods enabled comprehensive detection; however, IPA yielded more consistent and extensive metabolite coverage, identifying 43 lipids compared to only 15 with AcMeOH. We identified 15 metabolites that responded significantly to OA. Several metabolites, including the potential neuropeptide cycloprolylglycine and the exogenous compound curcumin, exhibited concentration changes under OA exposure, suggesting their potential relevance in stress response pathways triggered by environmental stress. Overall, we highlight IPA as a more effective extraction method for untargeted metabolomics in crustacean hemolymph. Our study elucidates metabolic dynamics that enhance our understanding of the physiological adaptability of marine crustaceans under environmental stress and provides a comprehensive dataset that for future OA research.
Continue reading ‘Untargeted mass spectrometry to investigate ocean acidification in Cancer borealis using optimized metabolite extraction methods’Northern shrimp exhibit origin-specific proteomic remodelling under ocean acidification, with limited response to ocean warming
Published 19 January 2026 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, multiple factors, North Atlantic, otherprocess, physiology, temperature
Highlights
- Ocean acidification, but not warming, drives proteomic response in Northern Shrimp.
- Shrimp from different origins show distinct molecular responses to ocean acidification.
- St. Lawrence shrimp display the strongest protein changes to ocean acidification.
- Local conditions shape how shrimp cope with global change drivers.
- Conservation plans must consider regional differences in shrimp responses.
Abstract
The Northern shrimp (Pandalus borealis) is an ecologically important species and the target of one of the world’Canas largest shellfish fisheries. Yet, its habitats are rapidly changing due to human-driven climate change, with temperatures projected to increase by ∼4 °C and seawater pH to decline by 0.3 pH units the end of the century. These stressors may cause interactive effects, with responses differing among origins due to local adaptation or long-term acclimatisation. We investigated the impacts of ocean warming and acidification (individually and combined) on the proteome of female P. borealis from four geographic origins. Shrimp proteomes responded to ocean acidification, but not to warming, with marked origin-specific differences. Comparing the most favourable condition (2 °C, pH 7.75) to low pH (7.35) across tested temperatures, we detected 109 differentially abundant proteins (DAPs) in shrimp from the Saint Lawrence Estuary (SLE), six in those from the Northeast Newfoundland Coast (NNC) and Eastern Scotian Shelf (ESS), and three in the Esquiman Channel (EC). SLE shrimp showed widespread downregulation across metabolic, genetic information processing, and signalling pathways, suggesting higher sensitivity to acidification relative to other origins, where responses were muted. These findings highlight intraspecific variation in proteomic responses to ocean acidification in this commercially valuable crustacean. They confirm ocean acidification as a major concern in the context of rapid environmental change and suggest that uniform conservation strategies may be ineffective. Instead, management efforts should account for origin-specific sensitivities, reflecting the complex adaptive landscape shaping the resilience of P. borealis and other exploited marine species.
Continue reading ‘Northern shrimp exhibit origin-specific proteomic remodelling under ocean acidification, with limited response to ocean warming’Reproduction of the viviparous marine isopod Cirolana harfordi held in seawater with raised temperature and lowered pH
Published 2 January 2026 Science ClosedTags: biological response, crustaceans, growth, laboratory, mortality, multiple factors, reproduction, temperature, zooplankton
Cirolanid isopods play important ecological roles as predators and scavengers, but when populations increase, they can form swarms that attack fish and humans. Understanding how the reproduction of cirolanid isopods will be affected by future warmer and more acidic oceans is therefore important. Samples of the viviparous species Cirolana harfordi were held in 4 combinations of 2 temperatures (18 and 24°C) and 2 pH levels (7.7 and 8.1), and the development of embryos and mancas was investigated by microscopic examination of each pregnant female through the transparent ventral cuticle of their thorax. Higher temperature increased the rate of development, thereby reducing pregnancy duration and accelerating the growth of mancas postpartum. By contrast, increased acidity had no significant effect on these parameters and had no deleterious effects on the development of the mancas. Higher temperature did not have a significant effect on the number of postpartum mancas after the 22 weeks that the adults spent in treatments. Increased temperature and/or lowered pH had no effect on the adult survival or growth. These data are in keeping with the hypothesis that C. harfordi may be able to withstand future warmer and more acidic oceans. Longer-term studies are needed to determine whether decreasing pregnancy durations in higher temperatures increases the number of times females can become pregnant over their lifetime, potentially leading to greater population numbers.
Continue reading ‘Reproduction of the viviparous marine isopod Cirolana harfordi held in seawater with raised temperature and lowered pH’Ocean acidification reduces juvenile snow crab, Chionoecetes opilio, survival but does not affect growth or morphometrics
Published 18 December 2025 Science ClosedTags: biological response, crustaceans, laboratory, morphology, mortality, North Pacific, reproduction
Highlights
- Snow crab were reared at 3 pHs for 396 days.
- Low pH did not affect size at molt.
- Low pH did not affect intermolt period.
- Survival was lower at a pH of 7.5 than at ambient or pH 7.8.
- Snow crab are moderately sensitive to ocean acidification.
Abstract
Anthropogenic release of CO2 and its subsequent dissolution in the oceans results in a decrease in the pH of seawater, known as ocean acidification, which can negatively affect marine organisms. Little is known about the response of snow crab, Chionoecetes opilio, to reduced pH. Juvenile snow crab were captured in the Bering Sea and exposed to three different pH treatments (Ambient (pH ∼7.95), pH 7.8, and pH 7.5) for 396 days at a constant temperature of 4 °C with thirty crabs randomly assigned to each treatment. Crabs were checked daily for molting or mortality. Wet mass and carapace morphometrics were measured after every molt. Reduced pH did not affect the intermolt duration, the carapace width after each molt, or wet mass of the crabs after each molt, giving no indication that growth rate was changed by reduced pH. There also was no change in morphometrics caused by reduced pH. However, the mortality rate of crabs held at pH 7.5 was 40 % higher than those held at pH 7.8 or Ambient. Such a substantial increase in mortality without accompanying sublethal effects is surprising; individuals susceptible to reduced pH might have died early in the experiment, or that differences in growth rate might have become apparent with longer exposure. Regardless, juvenile snow crab are somewhat sensitive to ocean acidification, although, consistent with studies at other life-history stages, snow crab may be more resistant to changes in pH than other Alaska crab species.
Continue reading ‘Ocean acidification reduces juvenile snow crab, Chionoecetes opilio, survival but does not affect growth or morphometrics’Stressed overwintering bottleneck hypothesis: ocean warming and acidification synergistically disrupt Arctic zooplankton overwintering
Published 1 December 2025 Science ClosedTags: Arctic, biological response, crustaceans, laboratory, molecular biology, mortality, multiple factors, physiology, reproduction, respiration, temperature, zooplankton
Ocean warming (OW), driven by the influx of warm Atlantic water masses, and acidification (OA) are threatening Arctic marine ecosystems. However, their potential synergistic effects are poorly understood, especially during the Polar Night when marine species are particularly vulnerable to stressors. Here, we tested our novel Stressed Overwintering Bottleneck Hypothesis (SOBH): warming will disrupt the overwintering of the keystone pan-Arctic copepod Calanus glacialis, a pivotal secondary producer, by impairing fitness-related traits underpinning survival and reproduction. We exposed C. glacialis to current and projected future OW levels (0 °C and 4 °C) and OA levels (pH 8.0 and 7.4-7.3) for 53 days during the mid-Arctic Polar Night. We assessed survival, development, and physiological and molecular mechanisms (oxygen consumption, lipid depletion, the expression of nine targeted genes related to oxidative stress and damage repair, and DNA damage). OW alone did not affect C. glacialis mortality; however, OA increased copepod survival at 0 °C. Notably, their combined effects (OWA) synergistically doubled mortality, as predicted by SOBH. Warming also accelerated moulting from copepodite stage V to adulthood in December, and increased respiration, exhausted lipid reserves entirely by early March, approximately one to four months before the spring algal bloom, further supporting SOBH. DNA damage and gene expression patterns indicated low investment in maintenance and damage repair. Collectively, these findings reveal hidden mechanisms by which OW and OA synergistically threaten overwintering Calanus copepods by drastically increasing mortality, accelerating moulting, raising metabolic rates, and causing early lipid depletion. These effects generate cross-seasonal phenological mismatches among overwintering survival, energy reserves, reproduction, and primary production. Such stressed overwintering bottlenecks in foundational secondary producers like Calanus copepods provide novel explanations for how OW and OA can constrict Arctic marine food webs. At a broader perspective, SOBH highlights how multiple stressors induced overwintering disruption could reshape pan-Arctic and global biodiversity.
Continue reading ‘Stressed overwintering bottleneck hypothesis: ocean warming and acidification synergistically disrupt Arctic zooplankton overwintering’Acidification-mediated perturbations of developmental pathways and life-stage transitions in Artemia salina
Published 27 November 2025 Science ClosedTags: biological response, crustaceans, fisheries, laboratory, mortality, reproduction
Projected increases in atmospheric carbon dioxide are anticipated to induce a 0.3–0.5 unit decline in oceanic pH by the year 2100, posing a significant threat to marine ecosystems. This study investigated the sub lethal effects of simulated ocean acidification on the ontogenetic success of Artemia salina, a key trophic link in aquaculture systems. A controlled, in vitro experiment employing a Completely Randomized Design (CRD) was conducted, maintaining constant temperature, salinity, and dissolved oxygen. Embryonic development and larval survival were assessed across a gradient of pH levels, representing projected future ocean acidification scenarios. Preliminary data indicate a negative correlation between decreasing pH and both hatching success and larval survivorship. Further investigations are warranted to elucidate the long-term ecological consequences of ocean acidification on Artemia salina populations and their role in aquaculture.
Continue reading ‘Acidification-mediated perturbations of developmental pathways and life-stage transitions in Artemia salina’Transcriptomic analysis of the hepatopancreas response to low-pH stress in kuruma shrimp (Marsupenaeus japonicus)
Published 6 November 2025 Science ClosedTags: biological response, crustaceans, fisheries, laboratory, molecular biology, North Pacific, physiology
Highlights
- Low-pH stress disrupted oxidative balance in M. japonicus, suppressing SOD and CAT activities while increasing MDA levels.
- Low-pH stress triggered 2705 DEGs in hepatopancreas linked to immunity, oxidative stress, and energy metabolism.
- CTSD, GLB1, and LGI4 are implicated in long-term immune adaptation to low pH.
- Key pathways—lysosome, Toll-like receptor, AMPK, and PPAR signaling—were activated under low pH stress.
- Hub genes such as NADH-GOGAT and MDHM were identified as central regulators of antioxidant defense and energy metabolism.
Abstract
Ocean acidification has emerged as a globally recognized environmental issue, posing a serious threat to marine ecosystems. To elucidate the adaptive mechanisms of Marsupenaeus japonicus under acidified conditions, both biochemical and transcriptomic analyses were performed following low-pH exposure. Biochemical assays revealed that low pH stress significantly SOD and CAT activities while markedly elevating MDA levels, indicating oxidative damage. T-AOC exhibited a transient rise followed by a sharp decline at later stages, suggesting initial activation and subsequent exhaustion of antioxidant defense. Transcriptomic profiling identified 2705 DEGs that were primarily enriched in pathways related to immune regulation, redox balance, apoptosis, and energy metabolism, including the lysosome, Toll-like receptor, and PPAR signaling pathways. Protein interaction analysis identified 9 hub genes, including NADH-GOGAT and MDHM, which may play key roles in antioxidant defense and metabolic regulation. The integration of enzyme activity and transcriptomic data indicates that acid stress initially induces oxidative imbalance, followed by compensatory activation of antioxidant and immune systems to restore cellular homeostasis. These findings provide comprehensive insights into the oxidative stress adaptation of M. japonicus and offer a genetic and physiological foundation for breeding acid-tolerant shrimp strains.
Continue reading ‘Transcriptomic analysis of the hepatopancreas response to low-pH stress in kuruma shrimp (Marsupenaeus japonicus)’DNA methylation plasticity drives copepod resilience to coastal high pCO2 and cadmium pollution under multigenerational exposure
Published 20 October 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, metals, molecular biology, mortality, multiple factors, North Pacific, otherprocess, reproduction, zooplankton
Highlights
- Fluctuating acidification caused the most Cd multigenerational toxicity in copepods.
- The adverse effects of acidification and Cd tended to intensify during F1-F3.
- The copepods potentially adapted to combined exposure in F4.
- DNA hypomethylation rendered copepods presenting the adaptive potential.
ABSTRACT
The vast majority of coastal organisms have been facing multigenerational scenarios of fluctuatingly high pCO2 and Cd pollution in their natural habitats. However, the adaptive capacity of these organisms to such combined stressors and the underlying mechanisms remain poorly understood. In this study, we conducted a multigenerational experiment (F1-F4) to investigate the adaptive responses of the marine copepod Tigriopus japonicus to combined fluctuatingly high pCO2 and Cd exposure, along with the associated mechanisms. Our findings revealed that steady high pCO2 aggravated Cd multigenerational toxicity, and it was more under fluctuating acidification. Notably, by the F4 generation, copepods potentially adapted to the combined stressors. Through transcriptomic and DNA methylation analyses of copepods from the F1 and F4 generations, we found that under combined exposure, F1 copepods likely reallocated more energy to counteract Cd toxicity; however, DNA hypermethylation inhibited Cd exclusion and detoxification/stress response pathways, ultimately compromising development and reproduction. In contrast, in the F4 generation, DNA hypomethylation enhanced processes such as cuticle repair program, compensatory mechanism (e.g., detoxification and immune response), and reproduction, consequently increasing the copepod’s fitness. These findings reveal an epigenetic basis for phenotypic acclimatization, offering marine copepods a supplementary mechanism to cope with combined stressors.
Continue reading ‘DNA methylation plasticity drives copepod resilience to coastal high pCO2 and cadmium pollution under multigenerational exposure’The bacterial community composition of American lobster (Homarus americanus) embryos and recently hatched larvae held under different temperature and acidification conditions
Published 16 October 2025 Science ClosedTags: biological response, BRcommunity, community composition, crustaceans, laboratory, molecular biology, multiple factors, North Atlantic, otherprocess, prokaryotes, reproduction, temperature
Previous research investigating the microbial community of American lobster embryos has long led researchers to believe this habitat comprised only a select few bacterial taxa. However, using 16S rRNA gene sequencing, we show this community to be more diverse than previously thought. We investigated how the bacterial communities of American lobster embryos and larvae change over embryogenesis and hatching in response to two environmental variables. Ovigerous female lobsters caught from Maine and Massachusetts were held under varying temperature and pH regimes that approximated observed and predicted warming and ocean acidification conditions in the Gulf of Maine (GoM) and Southern New England (SNE). The bacterial microbiome associated with the lobster embryos was quantified from two-time points during the experiment, and larvae were collected within 12 hours of hatching. Alpha diversity increased with each life history stage, and embryo and larvae microbiomes shared little community overlap with that in the surrounding tank water. Neither environmental conditions nor lobster origin significantly altered bacterial communities, with life history stage driving alpha and beta diversity. Embryos and larvae shared three core bacterial members identified as members of the genera Rubritalea, Delftia, and Stenotrophomonas. American lobster embryos and larvae appear to have a highly selective microhabitat for bacteria that is not altered by environmental conditions. This leads us to wonder what role the microbiome may have on a developing lobster, and where the microbiome is originating if not from the surrounding seawater.
Continue reading ‘The bacterial community composition of American lobster (Homarus americanus) embryos and recently hatched larvae held under different temperature and acidification conditions’Warming oceans may pose a serious threat to American lobsters
Published 15 October 2025 Press releases ClosedTags: biological response, crustaceans
The Gulf of Maine is warming faster than 99% of the world’s oceans, raising concerns for its $2 billion-a-year American lobster fishery. Scientists at William & Mary’s Batten School & VIMS have been studying the impacts of ocean acidification and warming on lobster reproduction, and the results of their most recent research suggest the rising temperatures pose the greatest risk.
Utilizing a purpose-built experimental facility designed by Professor Emily Rivest and housed in the Batten School of Coastal & Marine Sciences & VIMS’ Seawater Research Laboratory, the researchers exposed egg-bearing lobsters from the Gulf of Maine to water temperature and pH conditions that mimic those predicted for 2060. Published in the journal Marine Ecology Progress Series, the results revealed that the embryos can handle ocean acidification surprisingly well, but increased temperatures led to distinct stress responses that ultimately resulted in smaller larvae.
“American lobsters are dynamic creatures that have been shown to tolerate highly variable conditions as they move from coastal waters to the deeper ocean,” said the study’s lead author Brittany Jellison, who conducted the research as a postdoctoral scholar at the Batten School & VIMS. “However, as we observe rising ocean temperatures, increased acidification and more frequent marine heat waves, it’s important to understand how future environmental changes might impact this economically and culturally important species.”
Continue reading ‘Warming oceans may pose a serious threat to American lobsters’Effects of multiple stressors on embryos and emerging larvae of the American lobster
Published 14 October 2025 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, morphology, multiple factors, North Atlantic, otherprocess, physiology, reproduction, temperature
Environmental changes in the ocean can impose significant physiological costs and morphological changes to many marine organisms, and early life stages such as eggs and larvae are predicted to be particularly vulnerable to climate change drivers including warming and acidification. Although sensitivity to ocean change stressors during development has the potential to influence the performance, and ultimately the recruitment, of postlarvae and juveniles, the nature and strength of physiological modifications during embryo development is understudied in the ecologically and economically important American lobster Homarus americanus. We investigated the long-term, interactive impacts of ocean acidification and ocean warming on the development and physiology of brooded lobster embryos. We exposed ovigerous females to a combination of 2 temperatures and 2 pH levels for 5 mo, throughout which we measured development, metabolic rate, biochemical composition, and enzyme activity in their brooded embryos. The physiology of American lobster embryos appears to be robust to ocean acidification conditions but sensitive to warming, particularly for metabolic traits. We also found that warming induced a reduction in the size of freshly hatched larvae. Understanding how environmental change influences these early life stages of lobsters can improve predictions for how this species will fare in a changing ocean environment.
Continue reading ‘Effects of multiple stressors on embryos and emerging larvae of the American lobster’The effects of high seawater PCO2 on protein oxidative damage and ubiquitination in Penaeus vannamei
Published 13 October 2025 Science ClosedTags: biological response, crustaceans, laboratory, physiology
High environmental PCO2 in aquatic systems typically impairs physiology and performance in ectotherms; however, the effects of high PCO2 on protein degradation, a key process in protein homeostasis and growth, remain poorly understood. In this study, we investigated the effects of increasing environmental PCO2 (ambient, 5000 and 10,000 µatm) on metabolism, oxidative stress and protein ubiquitination (an indicator of protein degradation) in whiteleg shrimp (Penaeus vannamei). Standard metabolic rate was elevated by >2-fold at 5000 and 10,000 µatm PCO2, but this was not associated with increased post-prandial oxygen consumption or oxidative protein damage. However, levels of protein K48 ubiquitin were reduced by up to 10-fold at 10,000 µatm PCO2 compared with ambient controls, suggesting high PCO2 severely affects protein degradation. Our findings reveal that while P. vannamei appear resistant to elevated PCO2, fundamental modifications to protein degradation and homeostasis may affect long-term performance and growth in this species.
Continue reading ‘The effects of high seawater PCO2 on protein oxidative damage and ubiquitination in Penaeus vannamei’Molecular responses of amphipod (Parhyale darvishi), to pH stress in Persian Gulf
Published 10 October 2025 Science ClosedTags: biological response, crustaceans, Indian, laboratory, molecular biology, zooplankton
Climate change is driving more frequent and extreme pH fluctuations in intertidal habitats, yet the molecular mechanisms by which small crustaceans cope with acid–base stress remain poorly understood. In this study, we evaluated the transcriptional responses of the intertidal amphipod Parhyale darvishi to acute low-pH (6.0) and high-pH (9.0) challenges, simulating the extremes observed in tide pools. Following a 7-day acclimatization in aerated seawater (salinity 40–42 ppt, 24–25 °C, 12:12 h light:dark), individuals (4–7 mm length) were randomly assigned to one of three treatments: control (ambient pH 7.50–7.60), low pH (adjusted to 6.0 with 20 mL 37% HCl), or high pH (adjusted to 9.0 with 3 mL NaOH), each with two 1-L replicates containing 50 animals. After 0h, 12h and 24 h of exposure, total RNA was extracted and reverse-transcribed to cDNA. Real-time PCR assays quantified expression of five target genes: catalase (CAT), glutathione S-transferase (GST), Na⁺/K⁺-ATPase, apoptosis signal-regulating kinase 1 (ASK1), and caspase-3, with tubulin serving as the reference gene. Both pH stressors elicited significant transcriptional changes relative to controls. Under low pH, antioxidant genes CAT and GST were upregulated by approximately 2.5- and 2.1-fold, respectively, indicating activation of oxidative defense pathways. In contrast, high pH induced a more moderate antioxidant response (1.8- and 1.5-fold for CAT and GST) but triggered a pronounced apoptotic signal, with caspase-3 expression increasing nearly 3-fold. Na⁺/K⁺-ATPase transcripts rose under both treatments, reflecting osmoregulatory adjustments, while ASK1 exhibited a stronger induction in acid-stressed amphipods, suggesting stress-activated kinase signaling. These findings demonstrate that P. darvishi mounts distinct molecular responses to acid versus alkaline challenges, engaging antioxidant defenses under low pH and apoptosis-related pathways under high pH. Such differential gene expression profiles provide mechanistic insight into how intertidal amphipods cope with rapid pH swings, and underscore the utility of molecular biomarkers for assessing the resilience of coastal invertebrates under future acidification and alkalinization scenarios.
Continue reading ‘Molecular responses of amphipod (Parhyale darvishi), to pH stress in Persian Gulf’Acute, static, and fluctuating ocean acidification effects on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis
Published 8 October 2025 Science ClosedTags: biological response, crustaceans, laboratory, North Pacific, performance, physiology
Increases in atmospheric carbon dioxide (CO2) accelerate ocean acidification (OA), which has been shown to alter olfactory behaviours in marine organisms. Coastal regions currently experience pCO2 greater than end-of-century open ocean predictions with daily and seasonal fluctuations. Therefore, we hypothesized that marine organisms inhabiting the coastal regions are tolerant to the effects of OA. The acute, static, and fluctuating effects of acidification on the olfactory system were investigated in the coastal yellow shore crab (Hemigrapsus oregonensis (Dana, 1851)). After exposures, the olfactory behaviour to a food cue, putrescine, was measured, and changes in olfactory sensory receptors and neurons (OSNs) were determined using immunohistochemistry. Crabs took 3 times longer to locate the odorant and preferred it less after acute (minutes) and long-term (14 days) static exposures to OA. This impairment was correlated with a 16 to 30% decrease in olfactory receptor protein (IR25a) immunoreactivity and a 20% decrease in OSN volume. Crabs exposed to daily fluctuating pCO2 (7 days) displayed behavioural responses intermediate to crabs in control or static acidification conditions, and showed no changes in IR25a. These results indicate that despite their variable natural environment, yellow shore crabs are affected by acidification, being particularly vulnerable during sustained upwelling events (long-term static high pCO2).
Continue reading ‘Acute, static, and fluctuating ocean acidification effects on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis’Identifying and reducing climate uncertainty in fisheries management reference points
Published 15 September 2025 Science ClosedTags: biological response, communitymodeling, crustaceans, fisheries, modeling, socio-economy
Modelling has predicted that reductions in ocean pH and increases in temperature will reduce vital rates (survival and growth) of North Pacific crab stocks and hence the target levels of fishing mortality consistent with sustainable harvesting. However, these predictions have been based on the best estimates of the effects of changes in ocean pH and temperature on vital rates from laboratory experiments. We quantified the effects of several climate and market sources of variability in Alaskan red king and southern Tanner crab fisheries on predicted optimal fishing mortality rates, including changes in ocean chemistry and temperature on vital rates, non-linear relationships between prices, costs and catch, and the uncertainty in population dynamics models. The declines in survival consistently lead to predictions of a reduction in productivity and hence the optimal level of fishing intensity over time, but the extent of change is uncertain. Uncertainty related to the effects of ocean pH and temperature on vital rates and variability among Earth System Models and future emission scenarios are the dominant sources of uncertainty, although potential fluctuations in prices and costs are also consequential. Further, simulations are used to explore the relationship between changes in ocean pH or temperature and vital rates (additional experimental replicates and a wider range of levels of ocean pH in experiments) and hence identify approaches to reduce the uncertainty in estimates of future projections of target fishing mortality rates. Importantly, we demonstrate that optimal approaches to reducing uncertainty depend on life stage (juvenile growth for red king crab and larval survival for southern Tanner crab), and the optimal experiment depends on species (increasing the range of pH levels for red king crab vs increasing sample sizes for southern Tanner crab). The results of this study can inform priorities for future ocean acidification-related laboratory experiments and provide a basis for evaluating “investment in research” more broadly.
Continue reading ‘Identifying and reducing climate uncertainty in fisheries management reference points’A collaborative climate vulnerability assessment of California marine fishery species
Published 20 August 2025 Science ClosedTags: biological response, crustaceans, fish, fisheries, mollusks, North Pacific, policy, review
Climate change and the associated shifts in species distributions and ecosystem functioning pose a significant challenge to the sustainability of marine fisheries and the human communities dependent upon them. In the California Current, as recent, rapid, and widespread changes have been observed across regional marine ecosystems, there is an urgent need to develop and implement adaptive and climate-ready fisheries management strategies. Climate Vulnerability Assessments (CVA) have been proposed as a first-line approach towards allocating limited resources and identifying those species and stocks most in need of further research and/or management intervention. Here we perform a CVA for 34 California state-managed fish and invertebrate species, following a methodology previously developed for and applied to federally managed species. We found Pacific herring, warty sea cucumber, and California spiny lobster to be three of the species expected to be the most sensitive to climate impacts with California halibut, Pacific bonito, and Pacific hagfish expected to be the least sensitive. When considering climate sensitivity in combination with environmental exposure in both Near (2030–2060) and Far (2070–2100) Exposure climate futures, red abalone was classified as a species with Very High climate vulnerability in both periods. Dungeness and Pacific herring shifted from High to Very High climate vulnerability and Pismo clam and pink shrimp shifted from Moderate to Very High climate vulnerability as exposure conditions progressed. In providing a relative and holistic comparison of the degree to which state-managed marine fishery species are likely to be impacted as climate change progresses, our results can help inform strategic planning initiatives and identify where gaps in scientific knowledge and management capacity may pose the greatest risk to California’s marine resource dependent economies and coastal communities.
Continue reading ‘A collaborative climate vulnerability assessment of California marine fishery species’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’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’Ocean acidification decreases molting but not survival of Antarctic amphipods Djerboa furcipes, Gondogeneia antarctica, and Prostebbingia gracilis
Published 10 July 2025 Science ClosedTags: Antarctic, biological response, crustaceans, laboratory, morphology, mortality, physiology, zooplankton
Ocean acidification refers to a decrease in the pH of the world’s oceans from the oceanic uptake of human-derived atmospheric CO2. Low pH is known to decrease the calcification and survival of many calcifying invertebrates. Shallow, hard bottom communities along the Western Antarctic Peninsula often have incredibly large numbers of invertebrate mesograzers that shelter on and are mutualists with the dominant brown macroalgae. The common amphipod species Djerboa furcipes, Gondogeneia antarctica, and Prostebbingia gracilis were collected from the immediate vicinity of Palmer Station, Antarctica (64°46′S, 64°03′W) in January–February 2023 and maintained under three different pH treatments simulating ambient conditions (approximately pH 8.0), near-future conditions for 2100 (pH 7.7), and distant future conditions (pH 7.3) for 8 weeks. Molt number and mortality were monitored throughout the course of the experiment. After the 8 week exposure, amphipods were analyzed for their biochemical compositions including the Mg/Ca ratio of their exoskeletons. There was no significant difference in biochemical composition or survival among the pH treatments for any of the amphipod species. All three species, however, had significantly fewer total numbers of molts in the pH 7.3 treatment than in the ambient treatment. These results suggest that amphipods may be able to maintain their survival in decreased pH by reallocating energy into compensatory behaviors, such as acid–base regulation, and away from energy expensive processes like molting.
Continue reading ‘Ocean acidification decreases molting but not survival of Antarctic amphipods Djerboa furcipes, Gondogeneia antarctica, and Prostebbingia gracilis’
