The relationship between adverse environmental conditions and grooming behavior is an unresolved mechanism whereby a changing climate may impact reproductive success in animals that brood their eggs. Although important to embryo survival and development in decapod crustaceans, brood grooming by ovigerous females may be impacted by energetically demanding conditions associated with climate change, which may contribute to lethal and sublethal outcomes for brood health and survival. Despite its potential importance to reproduction, brood-grooming behavior has not been empirically described in the American lobster Homarus americanus H. Milne Edwards, 1837, a commercially important marine decapod. The relationship between brood-grooming behavior, temperature, and pH was explored at different points in the embryogenesis of American lobsters. For a period of 5 mo, egg-bearing females were exposed to different combinations of ecologically relevant conditions of temperature and pH, including those reflecting ocean warming (+4°C), ocean acidification (-0.5 pH), and the combination of warming and acidification. Fecundity, embryo development, and female grooming behavior were assessed at multiple time points. The proportion of time that lobsters spent fanning, but not probing, their broods increased with advancing embryo development. Neither egg loss, nor any measured brood-grooming behaviors, varied significantly with temperature or pH in this experiment. American lobster reproduction appears well suited to tolerate future conditions of ocean acidification and warming based on the ability to maintain stable brood grooming and brood mortality levels under a range of conditions.
Continue reading ‘Brood-grooming behavior of American lobsters Homarus americanus in conditions of ocean warming and acidification’Posts Tagged 'crustaceans'
Brood-grooming behavior of American lobsters Homarus americanus in conditions of ocean warming and acidification
Published 9 September 2024 Science ClosedTags: biological response, crustaceans, laboratory, mortality, multiple factors, North Atlantic, performance, reproduction, temperature
Species sensitivity distributions: understanding ocean acidification’s impact on marine biota
Published 30 July 2024 Science ClosedTags: biological response, cnidaria, crustaceans, echinoderms, fish, mollusks, phytoplankton, review, zooplankton
This research paper investigates the repercussions of ocean acidification on marine ecosystems, focusing on the sensitivity of diverse taxa to changing pH stages. Drawing from recent research, we discover the complicated interaction among climate change, contaminant accumulation, and atmosphere dynamics, with a particular emphasis on coastal regions reliant on fisheries. Through a complete assessment, we recognize substantial differences in sensitivity amongst calcifying taxa, highlighting the implications for each polar and temperate/tropical region. Furthermore, we propose tailored management techniques relying on distinct climate zones and taxonomic groups to mitigate the destructive effects of ocean acidification. Our sensitivity analyses monitoring of capability shifts in Species Sensitivity Distributions (SSDs) under preindustrial pH situations, underscoring the importance of historic baselines in predicting future influences. This paper contributes to our understanding of how ocean acidification threatens marine biodiversity and underscores the urgency of implementing efficient conservation measures.
Continue reading ‘Species sensitivity distributions: understanding ocean acidification’s impact on marine biota’Revisiting 20 years of coral–algal interactions: global patterns and knowledge gaps
Published 1 July 2024 Science ClosedTags: algae, biological response, BRcommunity, corals, crustaceans, echinoderms, protists, review
Coral–algal interactions are pivotal in reef ecosystems globally as they can scale up ecosystem levels and lead to dominance shifts. In this study, we conducted a systematic review of global coral–algal interactions, identifying the most studied locations, species, and types of interactions. We then assessed how these interactions may be impacted by consumers and climate change. Over the past 20 years (2001–2020), coral and algae interactions were mostly explored in the Pacific, and the Caribbean and US East Coast, where branching and massive corals were the focus, while other coral growth forms received less attention, and effects on algae were often overlooked. Adult corals were generally reported to be damaged when directly interacting with algae through physical abrasion or allelopathy. Conversely, algae interactions were found to have a positive impact on juvenile corals by facilitating larval recruitment and settlement. As expected, coral–algal interactions and the type of coral–algal relationships vary globally, most likely due to differences in abiotic conditions, community composition and the number of studies performed in a region. Despite the large emphasis on the role of consumers in controlling coral–algal interactions, few studies directly explored the effects of herbivory on coral–algal interactions. Given the growing evidence that ocean warming and acidification can reduce the competitive ability of corals, understanding the dynamic relationships between coral, algae, and consumers under future climate change conditions is crucial in predicting future coral recruitment potential and reef composition patterns. Here, we highlight the main findings from coral–algal interaction studies performed in the last 20 year and point to future directions, such as: 1) diversifying location, coral species, growth forms and life phases; 2) considering effects on both sides of interaction, not neglecting effects on algae; and 3) taking a closer look into the role of consumers and microbiomes. Advancing our understanding of coral–algal interactions, as well as how these interactions shift under changing conditions, is critical in predicting how coral reef ecosystems may operate in the future.
Continue reading ‘Revisiting 20 years of coral–algal interactions: global patterns and knowledge gaps’Red king crab larval survival and development are resilient to ocean acidification
Published 14 June 2024 Science ClosedTags: biological response, chemistry, crustaceans, laboratory, morphology, mortality, North Pacific, reproduction
Ocean acidification, a decrease in oceanic pH resulting from the uptake of anthropogenic CO2, can be a significant stressor for marine organisms. In this study, we reared red king crab larvae from hatching to the first crab stage in four different pH treatments: current surface ambient, diel fluctuation to mimic larval migration between the surface and mixed layer under current ambient conditions, pH 7.8, and pH 7.5. Larvae were monitored throughout development and the average length of each stage was determined. At each of the zoeal stages, the glaucothoe stage, and the first crab stage, we measured survival, morphometry, dry mass, and carbon, nitrogen, calcium, and magnesium content. Red king crab larvae were highly resilient to ocean acidification. There were no differences among treatments in survival or in average stage length. Although there were clear ontogenetic trends in size, weight, and elemental composition, most of these did not vary with pH treatment. Zoeal morphology did not vary among treatments, although glaucothoe and C1 crabs were slightly smaller in pH 7.8 than in the ambient treatment. Ambient larvae also had a slightly higher mass than pH 7.8 larvae but not pH 7.5. Ambient larvae had higher magnesium contents than pH 7.8 and pH 7.5, but calcium levels were the same. Ambient larvae also had slightly lower carbon and nitrogen content than pH 7.8 and pH 7.5 larvae but only in the 4th zoeal stage. Overall this study suggests that red king crab larvae are well adapted to a wide range of pH conditions and appear resilient to ocean acidification levels projected for the next two centuries.
Continue reading ‘Red king crab larval survival and development are resilient to ocean acidification’Lower seawater pH reduces the foraging activity of the Florida stone crab, Menippe mercenaria (Say, 1818) (Decapoda: Brachyura: Menippidae)
Published 3 June 2024 Science ClosedTags: biological response, chemistry, crustaceans, laboratory, North Atlantic, performance, physiology
Anthropogenic activities like habitat degradation, excess nutrient runoff, and sewage outfalls can decrease seawater pH in coastal environments. Coastal waters can also experience frequent fluctuations in seawater pH due to biological activity (i.e., photosynthesis and respiration). Commercially important species like the Florida stone crab, Menippe mercenaria (Say, 1818), inhabit coastal waters and experience fluctuations in seawater pH on both diurnal and seasonal scales. Organisms exposed to reductions in seawater pH may have difficulty sensing chemical cues due to physiological changes and the associated metabolic stress of compensating for a more acidic environment. Here we determined the foraging activity of the Florida stone crab when exposed to reduced pH conditions (control pH 7.8, reduced pH 7.6). The impacts of reduced pH on foraging activity were determined by monitoring activity time, stress, predation attempts, and handling time when crabs were exposed to lower seawater pH for 12 hrs. Crabs exposed to reduced pH conditions experienced elevated stress levels and reduced activity than crabs in the control pH treatment. These results suggest that exposure to more extreme pH conditions may limit the foraging activity of stone crabs.
Continue reading ‘Lower seawater pH reduces the foraging activity of the Florida stone crab, Menippe mercenaria (Say, 1818) (Decapoda: Brachyura: Menippidae)’Important but ignored: research progress on crab foraging behaviour and its implications for aquaculture
Published 24 May 2024 Science ClosedTags: biological response, crustaceans, fisheries, performance, review
Crab fisheries play a crucial role in global fishery economics, but they heavily rely on wild catches. With the decline and exploratory limits of wild populations, expanding the scale and production of aquaculture becomes vital for the sustainability of crab fisheries. The development of crab aquaculture encounters significant dietary challenges, stemming from suboptimal formulated feeds and inefficient feeding management. Leveraging insights from crab foraging behaviours offers a promising solution to these issues; however, progress is hindered by a lack of comprehensive behavioural data and the underappreciation of these insights in aquaculture. To bridge this gap, we systematically examine the progress in studies of crab foraging behaviour, analysing the influences of predators, prey, and environmental characteristics, and discuss possibilities for future research and development in the field by combining these findings with the demands of aquaculture. This review identifies a discrepancy in research focus, with inadequate emphasis on the major cultured species and their behavioural responses to factors limiting aquaculture productivity, aiming to enhance our comprehension of crab foraging behaviour and facilitate growth in the crab industry.
Continue reading ‘Important but ignored: research progress on crab foraging behaviour and its implications for aquaculture’Time-dependent changes in shrimp armor and escape kinematics under ocean acidification and warming
Published 13 May 2024 Science ClosedTags: biological response, chemistry, crustaceans, morphology, multiple factors, performance, physiology, temperature
Pandalid shrimp use morphological and behavioral defenses against their numerous fish and invertebrate predators. Their rapid tail-flip escape and rigid exoskeleton armor may be sensitive to changes in ocean temperature and carbon chemistry in ways that alter their efficacy and impact mortality. Here we tested the hypothesis that ocean warming and acidification conditions affect the anti-predator defenses of Pandalus gurneyi. To test this hypothesis, we exposed shrimp to a combination of pH (8.0, 7.7, 7.5) and temperature (13°C, 17°C) treatments and assessed their tail-flip escape and exoskeleton armor after short-term (2 weeks) and medium-term (3 months) exposure. Results revealed complex effects on escape kinematics, with changes in different variables explained by either pH, temperature, and/or their interaction; decreased pH, for instance, primarily explains reduced acceleration while cold temperature explains increased flexion duration. Carapace mineral content (Ca and Mg) was unaffected, but warmer temperatures primarily drove enhanced mechanical properties (increased hardness and stiffness). No effects were observed in the stiffness and strength of the rostrum. Furthermore, most of the observed effects were temporary, as they occurred after short-term exposure (2 weeks), but disappeared after longer exposure (3 months). This demonstrates that P. gurneyi defenses are affected by short-term exposure to temperature and pH variations, however, they can acclimate to these conditions over time. Nonetheless, changes in the tail-flip escape kinematics may be disadvantageous when trying to flee predators and the enhanced exoskeleton armor could make them more resistant to predation during short periods of environmental change.
Continue reading ‘Time-dependent changes in shrimp armor and escape kinematics under ocean acidification and warming’Functional diversity and metabolic response in benthic communities along an ocean acidification gradient
Published 1 May 2024 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, community composition, crustaceans, echinoderms, field, Mediterranean, mollusks, otherprocess, vents
Highlights
- Ocean acidification (OA) affect the distribution of traits within a community leading to the selection of specific functional traits.
- Along with the selection of traits, OA led to differences in oxygen consumption between benthic communities following acidification gradient.
- Altered acidified condition have a negative effect on the stability of the community resulting from changes in functional evennes of benthic communities.
Abstract
Altered ocean chemistry caused by ocean acidification (OA) is expected to have negative repercussions at different levels of the ecological hierarchy, starting from the individual and scaling up to the community and ultimately to the ecosystem level. Understanding the effects of OA on benthic organisms is of primary importance given their relevant ecological role in maintaining marine ecosystem functioning. The use of functional traits represents an effective technique to investigate how species adapt to altered environmental conditions and can be used to predict changes in the resilience of communities faced with stresses associated with climate change. Artificial supports were deployed for 1-y along a natural pH gradient in the shallow hydrothermal systems of the Bottaro crater near Panarea (Aeolian Archipelago, southern Tyrrhenian Sea), to explore changes in functional traits and metabolic rates of benthic communities and the repercussions in terms of functional diversity. Changes in community composition due to OA were accompanied by modifications in functional diversity. Altered conditions led to higher oxygen consumption in the acidified site and the selection of species with the functional traits needed to withstand OA. Calcification rate and reproduction were found to be the traits most affected by pH variations. A reduction in a community’s functional evenness could potentially reduce its resilience to further environmental or anthropogenic stressors. These findings highlight the ability of the ecosystem to respond to climate change and provide insights into the modifications that can be expected given the predicted future pCO2 scenarios. Understanding the impact of climate change on functional diversity and thus on community functioning and stability is crucial if we are to predict changes in ecosystem vulnerability, especially in a context where OA occurs in combination with other environmental changes and anthropogenic stressors.
Continue reading ‘Functional diversity and metabolic response in benthic communities along an ocean acidification gradient’Biological response of eelgrass epifauna, Taylor’s sea hare (Phyllaplysia taylori) and eelgrass isopod (Idotea resecata), to elevated ocean alkalinity
Published 18 April 2024 Science ClosedTags: biological response, chemistry, crustaceans, mollusks, mortality, physiology
Marine carbon dioxide removal (mCDR) approaches are under development to mitigate the effects of climate change with potential co-benefits of local reduction of ocean acidification impacts. One such method is ocean alkalinity enhancement (OAE). A specific OAE method that avoids issues of solid dissolution kinetics and the release of impurities into the ocean is the generation of aqueous alkalinity via electrochemistry to enhance the alkalinity of the surrounding water and extract acid from seawater. While electrochemical acid extraction is a promising method for increasing the carbon dioxide sequestration potential of the ocean, the biological effects of this method are relatively unknown. This study aims to address this knowledge gap by testing the effects of increased pH and alkalinity, delivered in the form of aqueous base, on two ecologically important eelgrass epifauna in the U.S. Pacific Northwest, Taylor’s sea hare (Phyllaplysia taylori) and eelgrass isopod (Idotea resecata), across pH treatments ranging from 7.8 to 9.3. Four-day experiments were conducted in closed bottles to allow measurements of the evolution of carbonate species throughout the experiment with water refreshed twice daily to maintain elevated pH. Sea hares experienced mortality in all pH treatments, ranging from 40 % mortality at pH 7.8 to 100 % mortality at pH 9.3. Isopods experienced lower mortality rates in all treatment groups, which did not significantly increase with higher pH treatments. Different invertebrate species will likely have different responses to increased pH and alkalinity, depending on their physiological vulnerabilities. Investigation of the potential vulnerabilities of local marine species will help inform the decision-making process regarding mCDR planning and permitting.
Continue reading ‘Biological response of eelgrass epifauna, Taylor’s sea hare (Phyllaplysia taylori) and eelgrass isopod (Idotea resecata), to elevated ocean alkalinity’Effects of pH on olfactory behaviours in male shore crabs, Carcinus maenas
Published 11 April 2024 Science ClosedTags: adaptation, biological response, chemistry, crustaceans, laboratory, North Atlantic, otherprocess, physiology, reproduction
The effects of climate change are becoming more apparent, predominantly concerning the impacts of ocean acidification on calcifying species. Many marine organisms rely on chemical signals for processes such as foraging for food, predator avoidance, or locating mates. The process of how chemical cues in marine invertebrates function, and how this sensory mode is affected by pH levels, is less researched. We tested the impact of reduced pH (7.6), simulating end-of-the-century predicted average ocean pH, against current oceanic pH conditions (8.2), on the behavioural response of male shore crabs Carcinus maenas to the female sex pheromone bouquet consisting of Uridine–diphosphate (UDP) and Uridine–triphosphate (UTP). While in current pH conditions (8.2), there was a significant increase in sexual interactions in the presence of female pheromone, males showed reduced sexual behaviours at pH 7.6. The crab weight–pH relationship, in which larger individuals respond more intensely sexually in normal pH (8.2), is reversed for both the initial detection and time to locate the cue. These results indicate that lowered pH alters chemical signalling in C. maenas also outside the peak reproductive season, which may need to be taken into account when considering the future management of this globally invasive species.
Continue reading ‘Effects of pH on olfactory behaviours in male shore crabs, Carcinus maenas’Narrowed gene functions and enhanced transposon activity are associated with high tolerance to ocean acidification in a juvenile subarctic crustacean
Published 11 April 2024 Science ClosedTags: biological response, chemistry, crustaceans, growth, laboratory, molecular biology, morphology, mortality, North Pacific, physiology, reproduction
Ocean acidification (OA) threatens marine crustaceans, particularly those at high latitudes where conditions are rapidly changing. Red king crab (RKC) support important fisheries in Alaskan waters. RKC early life stages are sensitive to OA when exposure occurs as embryos and juveniles. However, in a supporting study, RKC were surprisingly tolerant of varying OA conditions (pH 7.5, 7.8, & 8.0) when reared long-term from larval hatching to the first crab stage (C1). Here, we examined gene expression in the C1 juveniles to characterize transcriptional activity of these OA-tolerant crabs. Expression of nearly half of all genes (44%) correlated with OA treatment, suggesting a strong molecular response to OA, contrary to the phenotypic results. Downregulated functions were numerous in response to OA, and included reduced energy production, biosynthesis, immune function, and notably lipid and carbohydrate metabolic processes, which suggest a shift in metabolic strategy to protein catabolism, possibly to reduce CO2 production and facilitate acid/base regulation. Only a handful of functions were enriched in OA-induced genes, which were related to transcription regulation, control of growth and cell death, and signaling activity. Transposon activity was high in OA-reared crab, many of which were upregulated at consistent levels, suggesting that transposon mobilization may be a component of the RKC OA-response system. Genetic composition did not differ among OA treatments indicating that transcriptional differences in OA-reared crab were more likely attributed to phenotypic plasticity than selective mortality. Our results suggest that OA-reared RKC have a narrowed, possibly optimized, set of gene functions that enables OA-tolerance through the early juvenile stage. OA-exposure from hatch may benefit RKC and related species by “hardening” them against OA through physiological reprogramming. Future studies should test OA-hardened crabs in additional challenges, as metabolic and immune limitations may ultimately make them more vulnerable to infection or secondary stressors.
Continue reading ‘Narrowed gene functions and enhanced transposon activity are associated with high tolerance to ocean acidification in a juvenile subarctic crustacean’Disparate response of decapods to low pH: a meta-analysis of life history, physiology and behavior traits across life stages and environments
Published 5 April 2024 Science ClosedTags: biological response, calcification, crustaceans, growth, mortality, performance, physiology, reproduction, review
Highlights
- Predicted level of ocean acidification is a threat for calcifier marine invertebrates.
- Decapods, thought debatable, are presumably resilient.
- Our meta-analysis revealed few impacts that mainly vary across biological traits.
- Effect sizes little vary depending on the life stages and environments.
Abstract
We employed a meta-analysis to determine if the presumed resilience of decapods to ocean acidification extends to all biological aspects, environments, and life stages. Most response categories appeared unaffected by acidification. However, certain fitness-related traits (growth, survival, and, to some extent, calcification) were impacted. Acid-base balance and stress response scaled positively with reductions in pH, which maintains homeostasis, possibly at the cost of other processes. Juveniles were the only stage impacted by acidification, which is believed to reduce recruitment. We observed few differences in responses to acidification among decapods inhabiting contrasting environments. Our meta-analysis shows decapods as a group slightly to moderately sensitive to low pH, with impacts on some biological aspects rather than on all specific life stages or habitats. Although extreme pH scenarios may not occur in the open ocean, coastal and estuarine areas might experience lower pH levels in the near to medium future, posing potential challenges for decapods.
Continue reading ‘Disparate response of decapods to low pH: a meta-analysis of life history, physiology and behavior traits across life stages and environments’Fouling communities from the South African west coast are vulnerable to cooling and ocean acidification
Published 15 March 2024 Science ClosedTags: abundance, annelids, biological response, BRcommunity, bryozoa, chordata, community composition, crustaceans, fish, mollusks, multiple factors, otherprocess, prokaryotes, South Atlantic, temperature
Changing temperature and ocean acidification are well-recognised consequences of climate change in marine systems. In contrast to global trends, the South African west coast is experiencing cooling due to increased frequency and intensity of upwelling. The implications of concurrent cooling and acidification for marine biota are poorly understood, particularly at the community level. This laboratory study assessed how cooling and acidification might affect fouling communities along the South African west coast. Communities were experimentally exposed to two temperatures, 13℃ (current) and 9℃ (cooling), and three pH treatments, 7.9 (current), 7.6 and 7.4, for 18 days. Cooling and acidification altered community structure. Species diversity declined in response to acidification but was not affected by cooling. This was driven by greatest loss of species at 7.4 pH. Notably, acidification reduced the abundance of both calcifying and soft-bodied taxa, highlighting the vulnerability of taxa like ascidians to acidification. Overall, these results highlight the dominant threat posed by acidification, even for alien taxa that are often perceived as resilient to climate change. Additionally, in regions experiencing cooling, acidification may pose a greater threat to fouling communities than thermal changes.
Continue reading ‘Fouling communities from the South African west coast are vulnerable to cooling and ocean acidification’Physiological impacts of climate change on juvenile American lobster Homarus americanus (Decapoda: Astacidea: Nephropidae), a commercially important species
Published 6 March 2024 Science ClosedTags: abundance, biological response, BRcommunity, calcification, crustaceans, laboratory, morphology, multiple factors, North Atlantic, otherprocess, temperature
The American lobster, Homarus americanus, H. Milne Edwards, 1837 is an ecologically, economically, and culturally valuable marine resource for the coastal communities in the Gulf of Maine. Lobsters in the Gulf of Maine are experiencing the effects of rapid warming and acidification due to climate change. Lobster shells are comprised of chitin with precisely precipitated minerals (calcite, amorphous calcium carbonate, and carbonate apatite) that provide structural integrity to the shell and protection against predators and microbial intrusion. We examined the combined effects of ocean warming and acidification on shell mineralogy, epibiont abundance, and growth in early benthic juveniles. Lobsters were grown under six different temperature/pCO2 treatment conditions over 52 days (three replicates per treatment) aligned with environmentally relevant as well as predicted future extremes. Elevated pCO2 and temperature led to a decrease in shell calcium and magnesium content, suggesting that these environmental stressors inhibit shell biomineralization. There was an interactive effect of the stressors on epibiont abundance with the probability of epibiont coverage increasing with increasing pCO2 and temperature. Elevated pCO2 alone was significantly correlated (P = 0.002) to decreased growth, but only for female lobsters. Ocean acidification and warming significantly affect shell integrity in juvenile lobster, increasing risk to injury and disease with potential downstream consequences for the lobster fishery.
Continue reading ‘Physiological impacts of climate change on juvenile American lobster Homarus americanus (Decapoda: Astacidea: Nephropidae), a commercially important species ‘Alterations in network robustness upon simultaneous temperature and pH perturbations
Published 13 February 2024 Science ClosedTags: biological response, crustaceans, laboratory, multiple factors, North Atlantic, physiology, temperature
Nervous systems have evolved to function consistently in the face of the normal environmental fluctuations experienced by animals. The stomatogastric nervous system (STNS) of the crab, Cancer borealis, produces a motor output that has been studied for its remarkable robustness in response to global perturbations. Changes in environments are often complex and multifactorial. We studied the robustness of the pyloric network of the STG in response to simultaneous perturbations of temperature and pH. We compared the effects of elevated temperatures on the triphasic pyloric rhythm at control ,acid ,or base pHs. In each pH, recordings were made at 110C, and then the temperature was stepped up in 20C, increments, until the rhythms became disorganized, or “crashed”. As the temperature was raised, there were few obvious differences between the pyloric burst frequencies and phase relationships between the conditions, until close to the crash temperatures. Nonetheless, the temperatures at which the rhythms were disrupted were lower in the two extreme pH conditions. This indicates that one environmental stress can make an animal less resilient to a second stressor.
Continue reading ‘Alterations in network robustness upon simultaneous temperature and pH perturbations’Early stage ecological communities on artificial algae showed no difference in diversity and abundance under ocean acidification
Published 24 January 2024 Science ClosedTags: abundance, algae, annelids, biological response, BRcommunity, calcification, chemistry, community composition, crustaceans, echinoderms, field, Mediterranean, mesocosms, mitigation, mollusks, otherprocess, photosynthesis, protists, respiration
Marine habitat-forming species create structurally complex habitats that host macroinvertebrate communities characterized by remarkable abundance and species richness. These habitat-forming species also play a fundamental role in creating favourable environmental conditions that promote biodiversity. The deployment of artificial structures is becoming a common practice to help offset habitat loss although with mixed results. This study investigated the suitability of artificial flexible turfs mimicking the articulated coralline algae (mimics) as habitat providers and the effect of ocean acidification (OA) on early stage ecological communities associated to flexible mimics and with the mature community associated to Ellisolandia elongata natural turfs. The mimics proved to be a suitable habitat for early stage communities. During the OA mesocosms experiment, the two substrates have been treated and analysed separately due to the difference between the two communities. For early stage ecological communities associated with the mimics, the lack of a biologically active substrate does not exacerbate the effect of OA. In fact, no significant differences were found between treatments in crustaceans, molluscs and polychaetes diversity and abundance associated with the mimics. In mature communities associated with natural turfs, buffering capability of E. elongata is supporting different taxonomic groups, except for molluscs, greatly susceptible to OA.
Continue reading ‘Early stage ecological communities on artificial algae showed no difference in diversity and abundance under ocean acidification’Local scale extreme low pH conditions and genetic differences shape phenotypic variation in a broad dispersal copepod species
Published 24 January 2024 Science ClosedTags: adaptation, biological response, chemistry, crustaceans, field, molecular biology, morphology, otherprocess, reproduction, South Pacific
Extreme low pH events in estuaries and upwelling areas can modulate the phenotypic and genetic diversity of natural populations. To test this hypothesis, we explored the linkage between local scale extreme low pH events, genetic diversity, and variation in fecundity-related traits (body size, egg size, and egg production rate) in the broad-dispersal copepod Acartia tonsa. We assessed genetic and phenotypic characteristics of populations by contrasting extreme low pH environments (upwelling and temperate estuary) in the coastal Southeast Pacific, under natural and experimental conditions. These populations showed significant genetic differentiation with higher diversity in mitochondrial and nuclear loci (encoding mtCOI and 18S rRNA) in the estuarine population. Copepods from this population are exposed to more frequent extreme low pH events (< 7.7), and the adult females exhibit consistent phenotypic variation in body size, egg size, and egg production rate across different cohorts. Experimental acclimation to extreme low pH conditions revealed no significant differences in fecundity-related traits between A. tonsa populations. Although these results partially support our hypothesis, the experimental findings suggest other drivers might also influence phenotypic differences in the local environments.
Continue reading ‘Local scale extreme low pH conditions and genetic differences shape phenotypic variation in a broad dispersal copepod species’Impacts of ocean acidification and warming on the release and activity of the barnacle waterborne settlement pheromone, adenosine
Published 19 January 2024 Science ClosedTags: biological response, crustaceans, laboratory, multiple factors, North Pacific, performance, physiology, temperature
The effects of ocean acidification (OA) and warming on the physiological processes of many marine species have been well documented. However, far less is known about the impacts of these global variables on chemical communication. In this study, we identified the barnacle waterborne settlement pheromone (BWSP) of Balanus albicostatus as adenosine (Ado). Our results showed that neither elevated temperature (30 °C vs. ambient 26 °C) nor elevated pCO2 (1000 μatm vs. ambient 400 μatm) significantly affected the release of Ado from B. albicostatus adults. Exposure to elevated temperature and OA did not impair larval cue perception for settlement in B. albicostatus; however, OA inhibited settlement under elevated temperature in the absence/presence of BWSP, and elevated temperature induced larval settlement only in the presence of BWSP under ambient pCO2 condition. These results provided important insights into barnacle aggregation behavior in changing oceans and may help to predict the consequences of climate change on barnacle populations.
Effect of low pH on embryonic and larval traits in the estuarine semi-terrestrial crab Neohelice granulata
Published 11 January 2024 Science ClosedTags: biological response, crustaceans, laboratory, morphology, mortality, physiology, reproduction, South Atlantic
Introduction
The life cycle of marine invertebrates alternates between development phases which exhibit different physiological and ecological characteristics. The larvae (and sometimes the eggs) of most crustaceans, echinoderms, and mollusks, for example, are small and conventionally mobile, and they constitute the dispersive stages. In addition, larvae and embryos are considered in some traits less “complex” than adults, often lacking certain physiological mechanisms that allow advanced stages to cope with slight or even higher changes in the environment. However, early life stages are as important as subsequent instars; either population renewal, dispersion as connectivity, rely on the ability of these stages to overcome the adverse environmental conditions (Levin, 2006; DiBacco et al., 2006). As any impact observed in those early life phases will be deleterious to the whole population, functioning as a “bottleneck”, it is fundamental to understand the effect and capacity of response to the different stressors.
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Continue reading ‘Effect of low pH on embryonic and larval traits in the estuarine semi-terrestrial crab Neohelice granulata’
