Increases in atmospheric CO2 have led to more CO2 entering the world’s oceans, decreasing the pH in a process called ’ocean acidification’. Low pH has been linked to impacts on macroalgal growth and stress, which can alter palatability to herbivores. Two common and ecologically important macroalgal species from the western Antarctic Peninsula, the unpalatable Desmarestia menziesii and the palatable Palmaria decipiens, were maintained under three pH treatments: ambient (pH 8.1), near future (7.7) and distant future (7.3) for 52 days and 18 days, respectively. Discs of P. decipiens or artificial foods containing extracts of D. menziesii from each treatment were presented to the amphipod Gondogeneia antarctica in feeding choice experiments. Additionally, G. antarctica exposed to the different treatments for 55 days were used in a feeding assay with untreated P. decipiens. For D. menziesii, extracts from the ambient treatment were eaten significantly more by weight than the other treatments. Similarly, P. decipiens discs from the ambient and pH 7.7 treatments were eaten more than those from the pH 7.3 treatment. There was no significant difference in the consumption by treated G. antarctica. These results suggest that ocean acidification may decrease the palatability of these macroalgae to consumers but not alter consumption by G. antarctica.
Continue reading ‘Impacts of ocean acidification on the palatability of two Antarctic macroalgae and the consumption of a grazer’Posts Tagged 'performance'
Impacts of ocean acidification on the palatability of two Antarctic macroalgae and the consumption of a grazer
Published 27 February 2025 Science ClosedTags: algae, Antarctic, biological response, BRcommunity, crustaceans, laboratory, performance
Dynamics in brood chamber pH of the European flat oyster (Ostrea edulis) in response to ocean acidification
Published 13 February 2025 Science ClosedTags: biological response, laboratory, mollusks, multiple factors, North Atlantic, performance, physiology, temperature
Ocean acidification is posing a threat to marine bivalve species who struggle to deposit calcium carbonate in order to grow their shell. Some oyster species have developed a brooding reproductive strategy which might help them cope with this acidification stress. Brooding oysters have shown to be more resilient against ocean acidification than broadcast spawning oyster species. It is suspected that because the brood chamber is on top of the maternal gills, the mothers add carbon dioxide into the chamber from her respiration. This suggests larvae evolved to develop in a more acidic environment than the surrounding water column. Through exaptation the larvae may have coopted traits needed for development in the brood chamber which now enable them to be more resilient to ocean acidification. In this study, we measured the pH inside the brood chamber of Ostrea edulis under current and future predicted ocean conditions (i.e., elevated temperature and decreased seawater pH) to get a better understanding of the ambient-maternal relationship on brood chamber pH fluctuations under ocean acidification scenarios. The results suggested that maternal respiration indeed makes the brood chamber always a more acidified environment then the surrounding water. Elevated temperatures in the surrounding water slightly lower the pH as a result of increased maternal metabolism. Yet lowering the ambient pH causes a much larger and significant reduction of internal pH levels since the oyster is constantly filtering the overlaying water while the valves open. Additionally, there seems to be a positive relationship between shell gape and internal pH changes suggesting that the mothers behaviour may also influence how fast and to which level pH values can drop inside the brood chamber. These results give an indication of what conditions brooding oysters larvae will have to face in the future and helps determine possible winners and beneficial strategies in an acidified ocean.
Continue reading ‘Dynamics in brood chamber pH of the European flat oyster (Ostrea edulis) in response to ocean acidification’The effects of combined stress from pH and microplastic-derived odours on the European green crab Carcinus maenas’s olfactory behaviour
Published 12 February 2025 Science ClosedTags: biological response, crustaceans, laboratory, North Atlantic, performance
Simple Summary
The European shore crab, Carcinus maenas, also known as the European green crab, uses its sense of smell to detect prey, predators, and mating partners. Here, we examined how such crabs behave in environmental conditions that simulate the changes predicted by climate change. Crabs were exposed to female sexual odours, food smells, and various types of plastic leach outs. A decreased pH altered the crab’s behaviour towards food (Glutathione) and sex odour, reducing the animal’s response levels and increasing reaction times. Most interestingly, the crabs were more attracted to polyethylene (PE) odour in future ocean conditions, whilst males’ responses to female sex cues were especially reduced significantly. Response-level changes vary between the sexes, highlighting that understanding the effects of climate conditions on animal behaviour and choices is complicated and difficult to predict. That crabs become more attracted to plastic raises the question of what the bioactive chemicals are in PE that induce such a response, and this could demonstrate how climate change potentially increases the risks associated with plastic pollution in future oceans.
Abstract
Ocean acidification (OA) associated with climate change is expected to lower the ocean’s pH by 0.5 units by 2100. Whilst associated effects such as coral bleaching and shell calcification are well documented, lesser-known impacts are the ‘invisible’ effects on animal sensory systems. Olfactory disruption impacts the behaviour towards chemical cues in many marine species, including crustaceans. We examine the effects of microplastic odour and additional stressors on the European green crab C. maenas. Using uridine diphosphate (UDP) and uridine triphosphate (UTP) as a sex pheromone bouquet, glutathione (GSH) as a food cue, and polyethylene (PE) as plastic odour, cues were mixed with carboxycellulose to create slow-release gels. Crabs were exposed to gels in seawater pH values of 8.2, 7.6, and 7.2. Crabs took longer to react to all odours in reduced pH conditions (pH 8.2 to pH 7.2, p = 0.0017). At a low pH, PE-exposed crabs exhibited attraction towards microplastic odour and changed behavioural responses by burying. The study confirms low pH as disruptive to olfaction and highlights that plastic derivatives can become more bioactive at reduced pH levels, potentially increasing the threat posed by microplastic pollution. Further research is required to determine the potential long-term impacts of the combined threat of microplastics and reduced pH in the environment.
Continue reading ‘The effects of combined stress from pH and microplastic-derived odours on the European green crab Carcinus maenas’s olfactory behaviour’Behavioral and physiological effects of ocean acidification on juvenile American lobsters (Homarus americanus)
Published 12 February 2025 Science ClosedTags: biological response, crustaceans, laboratory, North Atlantic, performance, physiology
Alteration of pH within the world’s ocean, or ocean acidification (OA), results from increased absorption of CO2 into global waters. Acidification can positively or negatively affect physiology and behavior of marine taxa, though the effects vary greatly based on species and life stage. Crustaceans are often noted as being resilient to acidification, though negative physiological and behavioral impacts have been shown. Studies on the impacts of OA on the American lobster (Homarus americanus) have primarily focused on its physiology. This thesis aims to observe the potential effects of acidification on the foraging behavior and hemolymph chemistry of juvenile American lobsters. We exposed 28 juvenile lobsters (carapace length, CL, 29mm – 52mm, average 42 +/- 1.3mm) to randomly assigned, individual pH values between 7.3 and 7.8 for 12 days to observe potential impacts of acidification. The time taken to locate blue mussels, the number of foraging trips taken, the time taken to successfully feed, and hemolymph L-lactate concentration (stress indicator) were assessed after the exposure period. Counter to our predictions, as pH decreased, lobsters successfully fed two-times quicker, maintained normal locate times of prey, and took fewer foraging trips. We found that lobsters responsed to prey cues similarly across the pH range, indicating that olfaction was likely not impaired. These results suggest that juvenile American lobsters may increase foraging activity in response to acidified conditions.
Continue reading ‘Behavioral and physiological effects of ocean acidification on juvenile American lobsters (Homarus americanus)’Warming, but not acidification, increases metabolism and reduces growth of redfish (Sebastes fasciatus) in the Gulf of St. Lawrence
Published 6 February 2025 Science ClosedTags: biological response, fish, growth, laboratory, multiple factors, North Atlantic, performance, physiology, temperature
Understanding the effects of global change, including temperature, pH, and oxygen availability, on commercially important species is crucial for anticipating consequences for these resources and their ecosystems. In the Gulf of St. Lawrence (GSL), redfish (Sebastes spp.) have been under moratorium from 1995 to 2024, with a massive recruitment observed in 2011–2013. However, little is known about their metabolic and thermal physiology, making predictions of their response to changing GSL conditions challenging. To address this, we quantified the effects of four acclimatation temperatures (2.5, 5.0, 7.5, and 10.0 ℃) and two pH levels (7.35 and 7.75) on standard and maximum metabolic rates (SMR and MMR), aerobic scope (AS), hypoxia tolerance (O2crit), food consumption, and growth in redfish. SMR, MMR, and AS increased with temperature, but growth decreased at the highest temperature, likely due to increased metabolic demand, with food consumption similar across 5.0 to 10.0 °C treatments. O2crit was lower for fish acclimated to 2.5 and 5.0 ℃, making redfish less hypoxia-tolerant at higher temperatures. Except from SMR, no significant effect of pH was observed. These results suggest that future changes in the GSL will challenge redfish, with potential long-term effects on their growth due to increased energy requirements.
Continue reading ‘Warming, but not acidification, increases metabolism and reduces growth of redfish (Sebastes fasciatus) in the Gulf of St. Lawrence’Ocean acidification
Published 3 February 2025 Science ClosedTags: biological response, performance, review
Ocean acidification describes the decline in pH of marine environments as they continue to absorb anthropogenically derived carbon dioxide (CO2). Research over the past ~15 years has reported that levels of ocean acidification forecasted for the end of the century (CO2 ~800-1000 μatm; pH ~7.6-7.7) can severely impair behaviours of marine animals, including fishes and invertebrates. Impaired behaviours of most concern are those linked with neural and sensory systems, such as the capacity to respond appropriately to predators. However, after an initial proliferation of studies reporting dire behavioural disturbances, studies finding negligible effects of end-of-century ocean acidification began to accumulate. We have now reached a point where there is little consensus on whether, and how much, ocean acidification will impact animal behaviour. Here, we outline existing knowledge regarding the effects of ocean acidification on animal behaviour, discuss the chronology of discoveries and controversies in the field, and provide guidance for improving rigour and transparency in behavioural ecology more broadly.
Continue reading ‘Ocean acidification’Investigating the effects of environmental stress on coastal zooplankton populations: from mechanistic drivers to trophic impacts
Published 29 January 2025 Science ClosedTags: abundance, biological response, BRcommunity, crustaceans, field, laboratory, mortality, multiple factors, otherprocess, oxygen, performance, zooplankton
Environmental stressors, such as hypoxia and acidification, are increasing in intensity, duration, and extent in coastal waters and estuaries. Environmental stressors are known to affect a wide range of marine species, including zooplankton. Zooplankton are a critical link in marine food webs, connecting phytoplankton to higher trophic levels such as economically important fish, and are thought to be informative indicators of ecosystem change. For this reason, increased attention has been paid to understanding the mechanisms shaping zooplankton populations. Previous studies have shown that zooplankton exhibit both lethal and sublethal responses to changes in dissolved oxygen and pH. However, there is a range of species-specific responses to stressors. Different responses across species alter zooplankton community composition and spatial distributions, directly impacting predator-prey interactions and the trophic dynamics in coastal environments. This dissertation integrates laboratory experiments, in situ observations, and field work to understand how environmental stressors affect coastal zooplankton populations and nearshore food webs. In Chapter 1, I conducted laboratory experiments to investigate whether the copepod, Calanus pacificus, showed behavioral responses to stressors, and whether these responses lead to changes in vertical population distributions. Our laboratory experiments demonstrated significant effects of bottom water hypoxia and acidification on behavioral avoidance, swimming statistics, and apparent mortality rates in C. pacificus. In Chapter 2, I used a remote camera system to quantify in situ behavioral responses of zooplankton to stressors, using results from Chapter 1 to generate hypotheses about observations in the field. Our in situ videos revealed that copepods in stressful conditions exhibited significantly slower swimming speeds than copepods in non-stressful conditions, while amphipods showed significantly decreased abundances within stressful conditions. Finally, in Chapter 3, I collected zooplankton net tows in an intertidal estuary to investigate the transport of pelagic species into eelgrass beds and the role of eelgrass beds as potential sinks of pelagic zooplankton over the tidal cycle, potentially due to predation by juvenile fish. We found evidence of transport of pelagic species into intertidal habitats and measured large spatial and temporal variability, highlighting the need for sampling programs that can capture small-scale variability. This dissertation provides insight into the mechanisms that link the effects of environmental stressors across individual responses to population, community, and ecosystem level scales and suggests novel methodologies to help advance our understanding of changing zooplankton dynamics.
Continue reading ‘Investigating the effects of environmental stress on coastal zooplankton populations: from mechanistic drivers to trophic impacts’Physiochemical responses of an asterinid starfish (Echinodermata: Asteroidea) to global ocean change
Published 20 January 2025 Science ClosedTags: biological response, calcification, echinoderms, laboratory, mortality, multiple factors, performance, physiology, temperature
The continuous increase in greenhouse gas (GHG) emissions, especially carbon dioxide (CO2), since the beginning of global industrialization has resulted in significant alterations in seawater physicochemical properties, particularly elevated seawater temperatures (ocean warming, OW) and ocean acidification (OA). These changes have wide-ranging consequences for marine organisms, affecting their biological functions and ecological roles. The combined effects of OW and OA may amplify adverse outcomes compared to individual stressors due to the complex reorganization of cellular mechanisms and molecular pathways, which subsequently appear in behavioral modifications. However, organismal reactions and thresholds to these stressors are variable, which might differ within organism ontogeny or among taxa, making predictions challenging. Therefore, increasing research has been performed to better understand the potential mechanisms underlying the ability of marine organisms to alleviate the effects of environmental change, mainly due to OW and OA. Thus, employing multiple bioindicators, specifically keystone species such as starfish, to evaluate the impacts of OW and OA offers a comprehensive approach to examining their effects not simply on the organism concerned but also on the broader ecosystem.
The presented studies in this thesis aim to contribute to the understanding the role of physiochemistry and trade-offs on marine ectotherms, particularly asterinid starfish, in coping with environmental stress. For this purpose, mineralogic, metabolic, behavioral, lipidomics, and enzymatic activity approaches are used. The research summarized in this thesis provides the first investigation of the effects of global ocean change on biomineralization and physiological traits through long-term experiments using asterinid starfish species, Aquilonastra yairi, distributed in tropical to subtropical regions (across the Mediterranean Sea, Red Sea, and Gulf of Suez). The starfish were exposed to two temperature levels (27 °C and 32 °C) crossed with three pCO2 regimes (455 µatm, 1052 µatm, and 2066 µatm), representing factorial combinations of ambient conditions and future levels of CO2 and temperature change according to the IPCC-Representative Concentration Pathways (RCPs) 8.5 greenhouse gas emission scenario for the year 2100.
The present work revealed that asterinid starfish demonstrate high stressor tolerance and resilience to increased temperature and pCO2 through adaptive adjustments in physiological functions or behavioral activities, suggesting high homeostatic capacities and the ability to regulate physiochemical response to maintain survival, fitness, and metabolic biosynthesis under chronic conditions. The temperature was the predominant factor, exerting a significant effect on the magnitude and frequency of the affected physiological-related processes; however, concurrent exposure to OA and OW stress produced synergistic effects on some of the starfish physiology-related responses tested. While decreased pH negatively affects starfish calcification performance, the increased temperature potentially mitigates these effects. However, increased temperature might also lead to more magnesium (Mg2+) incorporation into the calcite lattice, potentially compromising the starfish skeleton. Furthermore, it was revealed that starfish can preserve lipid-associated biochemistry (FAs) under elevated temperature and pCO2, which potentially provides molecular instruments to cope with future OA and OW scenarios. However, combined OA and OW significantly affected Ca-ATPase and Mg-ATPase enzyme activities, which are recognized to play an important role in the biomineralization pathway, raising concerns about potential susceptibilities in skeletal development and preservation.
Investigating the complex impacts of global ocean change on marine organisms requires a comprehensive research approach that encompasses diverse biological, chemical, and physical traits. Understanding the physiological and chemical responses of bioindicator species, e.g., asterinid starfish, to combined stressors OW and OA is important to comprehend the relationships and interactions between biological processes and abiotic environmental conditions, which in turn essential for accurately predicting their resilience, ecological implication, and broader ecosystem dynamics. At the ecosystem scale, this study significantly contributes to the ongoing knowledge for future studies of the impact of climate change on coral reef-associated invertebrates. Specifically, this finding is beneficial for the conservation of coral reef ecosystems under future ocean conditions.
Continue reading ‘Physiochemical responses of an asterinid starfish (Echinodermata: Asteroidea) to global ocean change’Impacts of climate change on members of shallow water Antarctic communities
Published 16 January 2025 Science ClosedTags: algae, Antarctic, biological response, BRcommunity, community composition, crustaceans, laboratory, mortality, otherprocess, performance, physiology
Human-derived CO2 emissions have lowered the ocean’s pH and increased global temperatures. Low seawater pH can decrease the calcification, growth, and survival of calcifying invertebrates. Furthermore, low pH changes macroalgal growth and stress, possibly altering palatability to consumers. Global warming has decreased sea ice coverage, profoundly influencing photosynthetic organisms by altering subsurface irradiance. Shallow, hard-bottom communities along the Western Antarctic Peninsula are characterized by large macroalgal forests that shelter large numbers of mesograzers. Amphipods and macroalgae have a community-wide mutualistic relationship where macroalgae provide refuge from predatory fish while amphipods remove competing epiphytes. To understand how climate change could impact members of this relationship, macroalgal-associated mesograzers were collected near Palmer Station, Antarctica (64°46′S, 64°03′W) and maintained under three different pH treatments [ambient (pH 8.1), near-future (pH 7.7), and distant-future conditions (pH 7.3)] for 52 days. Total assemblage number and the relative proportion of each species were similar across the treatments, indicating possible resistance to short-term low pH exposure. The amphipods Djberboa furcipes, Gondogeneia antarctica, and Prostebbingia gracilis were maintained under the pH treatments for 8 weeks. No difference in biochemical composition or survival was found between the treatments for any of the species. However, each species decreased molt activity between the ambient and pH 7.3 treatment. These results suggest that amphipods may maintain their survival in decreased pH by reallocating energy into compensatory behaviors and away from energy-expensive processes like molting. The palatability of the unpalatable Desmarestia menziesii and the palatable Palmaria decipiens were maintained under three pH treatments and then presented to the amphipod Gondogeneia antarctica in a feeding choice assay. Decreased seawater pH generally lowered the consumption of both species, suggesting that acidification may decrease the palatability of these macroalgae to consumers. Finally, biochemical composition, carbon and nitrogen percentages, and C:N were correlated with sea ice indices for the macroalgae D. menziesii, Himantothallus grandifolius, Sarcopeltis antarctica, and Iridaea sp. from a sea ice gradient. Surprisingly, most of the chemical components were not correlated with sea ice cover, indicating sea ice coverage does not change the nutritional contributions of macroalgae to food webs.
Continue reading ‘Impacts of climate change on members of shallow water Antarctic communities’Will climate change alter the swimming behavior of larval stone crabs?: a guided-inquiry lesson
Published 23 December 2024 Science ClosedTags: biological response, crustaceans, education, multiple factors, performance, reproduction, temperature
The ocean has absorbed ~one third of the excess atmospheric carbon dioxide (CO2) released since the Industrial Revolution. When the ocean absorbs excess CO2, a series of chemical reactions occur that result in a reduction in seawater pH, a process called ocean acidification. The excess atmospheric CO2 is also resulting in warmer seawater temperatures. These stressors pose a threat to marine organisms, especially during earlier life stages (i.e., larvae). The larvae of species like the Florida stone crab (Menippe mercenaria) are free swimming, allowing a population to disperse and recruit into new habitats. After release, stone crab larvae undergo vertical swimming excursions in response to abiotic stimuli (gravity, light, pressure) allowing them to control their depth. Typically, newly hatched larvae respond to abiotic cues that would promote a shallower depth distribution, where surface currents can transport them offshore to complete development. As larvae develop offshore, they become less sensitive to certain abiotic stimuli, which promotes a deeper depth distribution that may expose them to variable current speeds, thus influencing the direction of advection (horizontal movement). Environmental stressors like ocean acidification and elevated seawater temperatures may also impact the larvae’s natural response to these abiotic stimuli throughout ontogeny (development). Changes in their natural swimming behavior due to climate stressors could, therefore, influence the transport and dispersal of the species. This guided-inquiry lesson challenges introductory marine biology and oceanography students to determine how future ocean pH and temperature projections could impact the swimming behavior of Florida stone crab larvae.
Continue reading ‘Will climate change alter the swimming behavior of larval stone crabs?: a guided-inquiry lesson’Ocean acidification and plankton
Published 10 December 2024 Science ClosedTags: biological response, community composition, otherprocess, performance, physiology, phytoplankton, review
Ocean acidification represents a significant and growing threat to some species of marine plankton, with wide-ranging implications for marine ecosystems and the services they provide. The alterations in plankton physiology, behavior, and community structure under acidified conditions exemplify the profound impact of anthropogenic CO₂ emissions on the ocean’s smallest, yet most essential inhabitants.
Continue reading ‘Ocean acidification and plankton’Physiological and behavioral responses of the Baltic clam Macoma balthica to a laboratory simulated CO2-leakage from a subseabed carbon storage site
Published 3 December 2024 Science ClosedTags: biological response, laboratory, mollusks, morphology, mortality, North Atlantic, performance, physiology
Highlights
- Baltic clams were exposed to CO2 leakage simulated in laboratory conditions.
- Physiological and behavioral responses of the model organism were evaluated.
- Shell growth in thickness and length were inhibited at pH 6.3.
- Biochemical composition, condition index and burrowing depth results were inconclusive.
Abstract
Carbon capture and storage in sub-seabed geological reservoirs is now officially included in the atmospheric CO2 emissions reduction policy and meets the agenda of Sustainable Development Goals (SDGs). Over the last few years biological risk assessment studies have delivered substantial empirical data on possible consequences of CO2 leakages from underwater storage sites on benthic systems. Current knowledge on Carbon Capture and Storage CCS associated risks is limited to marine systems. Yet there are multiple areas identified as suitable for carbon storage, but their hydrogeochemical features are so distinct that they should be studied as separate cases. Baltic Sea is one example of an area but is host to a unique – in a world scale – ecosystem with low salinity in combination with reduced oxygen availability in the benthic zone. Geological surveys have designated a potential storage site in the Southern Baltic Sea, namely the B3 oil field. Thus, this study focuses on biological effects of seawater acidification caused by a simulated CO2 leakage scenarios under laboratory conditions on a model macrobenthic in-faunal species. Baltic clams Macoma balthica were exposed to different environmental pH scenarios: pH 7.7 (no leakage), pH 7.0 (moderate hypercapnia) and pH 6.3 (severe hypercapnia) in three independent experiments conducted with the use of a hyperbaric tank (Karl Eric Titank) mimicking hydrostatic pressure of 900 kPa, relevant to conditions at the B3 field. Selected physiological aspects of the Baltic clam, such as survival, shell growth rate, morphometric condition and biochemical composition were investigated along with their behavioral responses, i.e. sediment burrowing activity. The results showed modest effects of hypercapnia on physiological performance of the clams that did not lead to greater mortality in neither of the tested leakage scenarios. Apart from high survival of the clams even in the lowest seawater pH (6.3) there were only little changes observed in the burrowing depth of the clams and biochemical composition of their soft tissues related to seawater acidification. The most evident physiological responses of the clams to prolonged hypercapnia (40 days at pH 6.3) were manifested in decreased shell growth.
The effects of ocean acidification on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis
Published 27 November 2024 Science ClosedTags: biological response, crustaceans, laboratory, molecular biology, North Pacific, performance, physiology
Increases in atmospheric carbon dioxide (CO2) lead to ocean acidification (OA) which has been shown to alter olfactory behaviours in marine organisms. However, coastal regions experience CO2 levels greater than end-of-century open ocean predictions. I investigated the effects of OA on the olfactory system of the intertidal yellow shore crab, Hemigrapsus oregonensis. I hypothesized that given their variable natural environment these crabs are more tolerant to OA. Crabs demonstrated impaired olfactory behaviour after acute and long-term static exposures to OA. This impairment was correlated with a decrease in olfactory receptor protein expression and a 20% decrease in olfactory sensory neuron volume. Crabs exposed to fluctuating CO2 had intermediate behavioural responses and showed no changes in receptor expression. These results show that coastal crabs are affected by ocean acidification despite their variable natural environment, being particularly vulnerable during upwelling events and this impairment will likely worsen in the future.
Continue reading ‘The effects of ocean acidification on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis’Cross-talk between tissues is critical for intergenerational acclimation to environmental change in Acanthochromis polyacanthus
Published 21 November 2024 Science ClosedTags: adaptation, biological response, fish, laboratory, molecular biology, otherprocess, performance, physiology, reproduction
Organisms’ responses to environmental changes involve complex, coordinated responses of multiple tissues and potential parental influences. Here using a multi-tissue approach we determine how variation in parental behavioural tolerance and exposure to elevated CO2 influences the developmental and intergenerational molecular responses of their offspring in the coral reef fish Acanthochromis polyacanthus to future ocean acidification (OA) conditions. Gills and liver showed the highest transcriptional response to OA in juvenile fish regardless of parental OA conditioning, while the brain and liver showed the greatest intergenerational acclimation signals. Developmentally induced signals of OA, such as altered neural function in the brain, were restored to control levels after intergenerational exposure. Intergenerational CO2 exposure also enabled the offspring to adjust their metabolic processes, potentially allowing them to better meet the energetic demands of a high CO2 environment. Furthermore, offspring of OA-exposed parents differentially expressed a new complement of genes, which may facilitate intergenerational acclimatory responses. A genetic component of intergenerational plasticity also played a crucial role, with the parental behavioural phenotype largely determining the offspring’s transcriptional signals. Overall, our results reveal tissue-specific transcriptional changes underlying intergenerational plastic responses to elevated CO2 exposure, enhancing understanding of organismal acclimation to OA throughout the whole body.
Continue reading ‘Cross-talk between tissues is critical for intergenerational acclimation to environmental change in Acanthochromis polyacanthus’Combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in Chinese mitten crab Eriocheir sinensis
Published 6 November 2024 Science ClosedTags: biological response, BRcommunity, crustaceans, laboratory, performance, physiology, prokaryotes
Highlights
- Low pH stress might disturb the maintaining of protein homeostasis in hemocytes.
- Combination of low pH stress and bacterial infection cause disruption of TLR pathway.
- Low pH stress and bacterial infection inhibit the TCA cycle in hemocytes.
Abstract
Water pH is a critical environmental factor for aquaculture. Acidification is a pressing environmental issue that poses significant threats to the aquaculture industry. Since the outbreaks of disease generally accompany with environmental stress, comparative transcriptome analyses were performed to investigate the combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in the economically important crab Eriocheir sinensis. The results revealed that the immune deficiency (IMD) pathway and prophenoloxidase (proPO) system was activated to defense against Vibro parahaemolyticus even when crabs were subjected to low pH stress, whereas low pH stress resulted in the disorder of Toll-like receptor (TLR) pathway upon V. parahaemolyticus infection. Moreover, low pH stress might weaken crabs′ defense against V. parahaemolyticus by inhibiting the up-regulation of crustin and suppressing the expression of lysozyme, and disturb the maintaining of protein homeostasis through the transcriptional decrement of a batch of heat shock proteins (HSPs). It is worth noting that both V. parahaemolyticus infection and low pH stress might suppress the energy metabolism in the hemocytes via inhibiting the expression of critical enzymes, dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex and fumarase, in the tricarboxylic acid (TCA) cycle. This study provides novel understandings concerning the transcriptional changes of hemocyte in E. sinensis subjected to a combination of low pH stress and V. parahaemolyticus infection as well as contribute to optimize the management strategies for the prevention and control of diseases in E. sinensis farming.
Continue reading ‘Combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in Chinese mitten crab Eriocheir sinensis’Improved growth performance and physiological state in hybrid abalone (Haliotis rufescens and Haliotis fulgens) facing ocean acidification conditions
Published 1 November 2024 Science ClosedTags: biological response, BRcommunity, mollusks, morphology, mortality, performance, physiology, respiration
Highlights
- Hybrid vigor in abalones evaluated under future ocean acidification scenarios.
- Hybrid cross abalone show positive heterosis on biological performance.
- More robust metabolic response observed in hybrids than in pure abalone crosses.
- Higher heterosis for survival and shell growth reached at pH 7.8 conditions.
- Interspecific hybridization yield resilient cross withstand ocean acidification.
Abstract
Abalone (Haliotis spp.) is a valuable global aquaculture resource in Mexican abalone industry, particularly red (Haliotis rufescens) and green (H. fulgens) abalone, showing significant growth. However, climate change -particularly ocean acidification (OA)- threatens production by negatively impacting mollusks, leading to recruitment failures, poor fertilization, malformations, and reduced calcification and growth jeopardizing sustainability and food security. This study aims to assess robustness of a hybrid abalone cross RF (H. rufescens ♀ x H. fulgens ♂) to OA conditions by evaluating biological performance (survival, growth in weight and length) and metabolic response (oxygen consumption, ammonia excretion rate, and atomic O:N ratio). Juveniles from hybrid RF cross and two pure parental crosses (RR, FF) were exposed to three pH levels: control (pH ≈ 8.0) and two reduced pH scenarios (pH 7.8 and 7.5), representing moderate and severe OA conditions. The results showed hybrid cross exhibiting better growth and metabolic response than pure crosses under all conditions. Notably, hybrid length growth was superior under moderate OA conditions (pH 7.8) compared to control (pH 8.0) and intense OA conditions (pH 7.5). Enhanced physiological hybrid status was evidenced by increased oxygen consumption and stable ammonia excretion, reflected in higher atomic O:N ratio. This study demonstrates hybrid cross RF robustness under OA conditions and supports interspecific hybridization as potential mitigation strategy to alleviate negative OA effects for sustainable abalone production.
Continue reading ‘Improved growth performance and physiological state in hybrid abalone (Haliotis rufescens and Haliotis fulgens) facing ocean acidification conditions’Chapter 6 – Impacts of ocean acidification on the behavior of marine mollusks
Published 22 October 2024 Science ClosedTags: biological response, BRcommunity, laboratory, mollusks, performance
Ocean acidification, a direct consequence of increasing carbon dioxide (CO2) emissions, is a pressing environmental issue that has far-reaching implications for marine ecosystems (Doney et al., 2009). The oceans absorb approximately one-third of the CO2 produced by human activities, leading to decreased seawater pH, a process known as ocean acidification (Rodriguez, 2012). This phenomenon has been identified as a significant threat to marine life, mainly invertebrates such as mollusks, echinoderms, and crustaceans, which rely on carbonate ions to build their shells and skeletons (Guinotte and Fabry, 2008; Doney et al., 2020).
Continue reading ‘Chapter 6 – Impacts of ocean acidification on the behavior of marine mollusks’Ecophysiology and ocean acidification in marine mollusks: from molecule to behavior
Published 17 October 2024 Science ClosedTags: biological response, education, growth, mollusks, morphology, performance, physiology, reproduction, review, socio-economy
Ecophysiology and Ocean Acidification in Marine Mollusks: From Molecule to Behavior provides an extensive overview of the latest research on the various ecophysiological effects of ocean acidification on marine mollusks. This book synthesizes historical information and recent findings on the effects of environmental change, ocean warming, and acidification on key mollusks and their life-history. It also discusses the underlying mechanisms underpinning the effects of ocean warming and acidification. Written by internationally recognized experts in the field of marine biology, this book systematically examines the effects of ocean acidification on the reproduction, growth and development, physiological metabolism, immunity, and behavior of marine mollusks.
The book concludes by discussing the implications of current research, acknowledging data limitations in the field, and proposing future research directions, providing a better understanding of the potential impacts of ocean acidification on mollusks and the global aquaculture industry and inspiring new thinking for future research practices. It will be an indispensable resource for researchers, practitioners, undergraduate and graduate students, conservationists, and aquaculturists alike who are interested in marine environmental change, ecology, physiology, and marine biology.
Continue reading ‘Ecophysiology and ocean acidification in marine mollusks: from molecule to behavior’Mutligenerational chronic exposure to near future ocean acidification in European sea bass (Dicentrarchus labrax): insights into the regulation of the transcriptome in a sensory organ involved in feed intake, the tongue
Published 10 October 2024 Science ClosedTags: biological response, BRcommunity, fish, laboratory, molecular biology, performance, physiology
Highlights
- Multigenerational exposure to OA has no impact on teeth mineralization in Sea bass.
- Of the 18703 genes expressed in the tongue, 295 exhibited OA-induced regulation.
- Genes related to cell stress, immune system and fatty acid sensitivity are regulated.
- OA impacts the branchial expression of p2ry4 gene involved in gustatory system.
Abstract
In this study, we examined the effect of near future ocean acidification (OA) on the transcriptome of a sensory organ in contact with surrounding water, the tongue in adult European sea bass (Dicentrarchus labrax) by mean of RNAseq experiment. We acquired a total of 14.1 Mb quality-trimmed reads covering 18,703 expressed genes from the tongue of fish reared from two generations at actual (pH 8.0 condition) and predicted near-future seawater pH (pH 7.6 condition). Gene ontologies analyses of expressed genes support the evidence that the tongue exhibits biological processes related to the sensory system, tooth mineralization and immune defences among others. Our data revealed only 295 OA-induced regulated genes with 114 up- and 181 down-regulated by OA. Functions over-represented encompass processes involved in organic substance metabolic process, RNA metabolism and especially RNA methylation which, combined with the regulation of some hsp genes expression, suggest a molecular response to stress which might contribute to lingual cell homeostasis under OA. The immune system process is also found enriched within OA-induced regulated genes. With the exception of one fatty acid receptor, known taste perception effectors were not impacted by OA in the tongue. However, a complementary droplet digital PCR approach dedicated to genes involved in gustatory signal transduction revealed the down regulation by OA of pyrimidinergic receptor (p2ry4) transcript expression in the gills of the fish. Combined with scanning electron microscopy analysis, our RNAseq data revealed that OA has no impact on processes related to teeth development and mineralization. Altogether, our data reveal that multigenerational exposure to OA has not a substantially effect on the tongue transcriptome but emphasis should be placed on investigating the potential physiological consequences related to the regulation of genes related to cell stress, immune system and fatty acid sensitivity to conclude on species resilience in face of OA.
Continue reading ‘Mutligenerational chronic exposure to near future ocean acidification in European sea bass (Dicentrarchus labrax): insights into the regulation of the transcriptome in a sensory organ involved in feed intake, the tongue’Impact of low pH/high pCO2 on the physiological response and exopolysaccharide content in cyanobacteria Trichodesmium erythraeum
Published 26 September 2024 Science ClosedTags: biological response, BRcommunity, growth, laboratory, morphology, performance, prokaryotes
The acidification of the ocean caused by the diffusion of anthropogenic carbon dioxide (CO2) into seawater has been believed to threaten the stability of the marine ecosystem. As one of the major contributors to the primary production in oligotrophic oceans, the response of Trichodesmium to the acidification of the ocean has attracted a lot of attention. Therefore, in this study, we applied physiological and biochemical methods to identify the influences of high pCO2 and low pH conditions on the growth of T. erythraeum. Our results showed that the low pH during the acidification of the ocean was the main factor inhibiting the growth of T. erythraeum. In addition, low pH caused oxidative stress to T. erythraeum, as evidenced by the increase of the reactive oxygen species and antioxidant enzyme’s activities. The activity of carbonic anhydrase (CA) enzyme is dually regulated by pCO2 and pH, and T. erythraeum can adapt to different levels of pCO2 and pH in seawater by flexibly adjusting CA enzyme activity. We also discovered that the stimulatory effect of high pCO2 on the exopolysaccharide (EPS) content of T. erythraeum outweighed the inhibitory effect of low pH during the process of ocean acidification. In conclusion, this study systematically revealed the effects of high pCO2 and low pH caused by the acidification of the ocean on the growth and EPS of T. erythraeum. These results provide new insights into the response mechanisms of T. erythraeum in the acidified ocean under future climate conditions.
Continue reading ‘Impact of low pH/high pCO2 on the physiological response and exopolysaccharide content in cyanobacteria Trichodesmium erythraeum’
