Phenotypic plasticity and evolutionary adaptation allow populations to cope with global change, but limits and costs to adaptation under multiple stressors are insufficiently understood. We reared a foundational copepod species, Acartia hudsonica, under ambient (AM), ocean warming (OW), ocean acidification (OA), and combined ocean warming and acidification (OWA) conditions for 11 generations (approx. 1 year) and measured population fitness (net reproductive rate) derived from six life-history traits (egg production, hatching success, survival, development time, body size and sex ratio). Copepods under OW and OWA exhibited an initial approximately 40% fitness decline relative to AM, but fully recovered within four generations, consistent with an adaptive response and demonstrating synergy between stressors. At generation 11, however, fitness was approximately 24% lower for OWA compared with the AM lineage, consistent with the cost of producing OWA-adapted phenotypes. Fitness of the OWA lineage was not affected by reversal to AM or low food environments, indicating sustained phenotypic plasticity. These results mimic those of a congener, Acartia tonsa, while additionally suggesting that synergistic effects of simultaneous stressors exert costs that limit fitness recovery but can sustain plasticity. Thus, even when closely related species experience similar stressors, species-specific costs shape their unique adaptive responses.
Continue reading ‘Simultaneous warming and acidification limit population fitness and reveal phenotype costs for a marine copepod’Posts Tagged 'crustaceans'
Simultaneous warming and acidification limit population fitness and reveal phenotype costs for a marine copepod
Published 8 September 2023 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, morphology, mortality, multiple factors, otherprocess, reproduction, temperature, zooplankton
Chapter 12 – Climate change and multiple stressors
Published 25 August 2023 Science ClosedTags: biological response, crustaceans, review
In this review we assess and predict the impacts of climate change on the ecophysiology and distribution of Carcinus maenas—the green or five-spine shore crab—based on research to date on this and other marine invertebrates. Warming is expected to minimally affect C. maenas because of its broad thermal tolerances, planktotrophic development, and capacity for rapid adaptation; however, the embryos and larvae are more sensitive to environmental drivers, so the species may be more restricted than expected by adults alone. The impacts of ocean acidification are mostly expected to be minimal, as for other crustaceans. The osmoregulatory capacity of the euryhaline Carcinus genus means it is already adapted to fluctuating salinities. Furthermore, in many cases the effect of combining environmental drivers seems to minimize their joint impacts on C. maenas. Strong currents and upwelling may enhance recruitment but have less predictable effects. Finally, we echo predictions of further poleward range expansion of C. maenas as the climate warms. We conclude that C. maenas is well positioned to face minimum impacts from global change.
Continue reading ‘Chapter 12 – Climate change and multiple stressors’Estuarine shellfish and climate change
Published 14 August 2023 Science ClosedTags: biological response, crustaceans, echinoderms, mollusks, review
Over centuries, shellfish populations have directly and indirectly benefitted humans living in coastal communities by providing fisheries and ecosystem services. The naturally dynamic estuarine environment, home to many economically important shellfish populations is, however, also commonly subjected to anthropogenic pressure from exploitation, pollution, and the acceleration of climate change. Climate change alters the rate and direction of long-term biogeochemical change in the ocean, but also, in combination with large-scale climate oscillations and other factors, can modulate the frequency, persistence, and/or magnitude of extreme coastal events including estuarine heatwaves, coastal hypoxia, and coastal acidification. This chapter explores the dynamic variability of the estuarine environment and assesses the impacts of climate stressors in isolation and in combination with other climatic/anthropogenic stressors on estuarine shellfish species. Individually, warming temperatures can alter the rates of physiological processes and can result in changes in growth and reproduction, while extremes in temperature can elicit physiological stress, mortality, or even local extinctions. Range contractions or expansions resulting from shifts in temperature or salinity can have cascading effects on ecosystem functioning, as important functional roles associated with shellfish (i.e., suspension-feeding, habitat engineering, bioturbation, predation) are gained or lost. Since nearly all shellfish species produce calcified structures exposed to the external environment, increasing CO2 concentrations and extremes in CO2 can have negative consequences on calcification that may vary by life stage and may have fitness-related consequences. Low oxygen extremes, which may become more persistent or severe under warming temperatures, consistently yield negative effects on the growth, development, metabolism, reproduction, survival, and/or abundance of mollusks and crustaceans and, thus, can have disproportionate impacts on ecosystem functioning.Estuaries commonly host co-occurring extremes (e.g., hypoxia and acidification), forcing organisms to cope with multiple stressors. Multi-stressors, an emerging field of research, can have a range of additive, synergistic, and antagonistic effects on shellfish species, with additional stressors typically yielding more negative outcomes than single stressors. Still, there are many unknowns regarding the potential effects of climate change syndromes on coastal shellfish, particularly in dynamic estuarine environments, and examinations of the combined impacts of warming/hypoxia/acidification and/or harmful algal blooms have only just begun. Autonomous observing platforms and high-frequency sensor arrays are essential to generating long-term and fine-scale time series datasets to characterize the shifting biogeochemical patterns under climate change. It will also be critical to scale up physiological studies to assess impacts on populations, communities, and ecosystems. Finally, to protect and/or restore shellfish resources, continued collaboration between communities and researchers on adaptive strategies that mitigate harm to shellfish populations experiencing extremes in future change will be vital.
Continue reading ‘Estuarine shellfish and climate change’Responses of marine macroalgae to climate change drivers
Published 11 August 2023 Science ClosedTags: biological response, crustaceans, echinoderms, mollusks, review
Climate changes are progressively altering global ocean environments, leading to ocean acidification and warming, marine heatwaves, deoxygenation, and enhanced exposure of UV radiations within upper mixing layers. Marine macroalgae are affected by these environmental changes in coastal waters, where changing magnitudes of these drivers are usually larger than in open oceans. While macroalgae have developed physiological mechanisms to cope with these stressors, their responses to or tolerances to these stressors are species-specific and spatiotemporally variable. Fleshy macroalgal species are commonly capable of tolerating moderate decline of pH and diel fluctuations of pH, and their growth and photosynthesis can be enhanced by elevated CO2 concentrations in seawater and in the air during emersion at low tides. However, macroalgal calcifiers are especially sensitive to ocean acidification, with their calcification being reduced, which exacerbates the harm of solar UV radiation due to thinned protective calcareous layers. Marine warming and heatwaves, however, may endanger most macroalgal species as their seasonality of life cycle is temperature-dependent. Macroalgae either distributed in upper or lower intertidal zones are susceptible to UV radiation, which may have negative, neutral, or beneficial effects on them, depending on the levels of UV and other factors. UV-A (315–400 nm) can stimulate the photosynthesis of macroalgae under low to moderate levels of solar radiation; however, UV-B (280–315 nm) mainly causes negative effects. While the combined effects of elevated temperature, CO2, and UV radiation have rarely been documented, exposures to marine heatwaves and high levels of UV can be fatal to microscopic stages of macroalgae. Apart from the species found in estuaries, the physiology and community structure of macroalgae can be influenced by reduced salinity and pH associated with rainfall and/or terrestrial runoffs. Nevertheless, reduced O2 availability associated with ocean deoxygenation and/or hypoxia, promoted by eutrophication and ocean warming, may favor macroalgal carbon fixation because of suppressed photorespiration due to reduced O2 vs. CO2 ratios, although little documentation exists to support this possibility. While macroscopic stages of macroalgae are resilient or even benefit from some of the drivers, their microscopic stages and/or juveniles are susceptible to ocean climate changes, and the sustainability of their life cycles is endangered. In this chapter, we review and analyze the responses of different macroalgal groups and different life cycle stages to climate change drivers individually and/or jointly based on the literature surveyed, along with perspectives for future studies on the multifaceted effects of ocean climate changes.
Continue reading ‘Responses of marine macroalgae to climate change drivers’The reproductive capacities of the calanoid copepods Parvocalanus crassirostis and Acartia pacifica under different pH and temperature conditions
Published 4 August 2023 Science ClosedTags: biological response, crustaceans, Indian, laboratory, multiple factors, reproduction, temperature, zooplankton
The increasing atmospheric CO2 concentrations and warming of marine waters have encouraged experiments on multi-stressor interactions in marine organisms. We conducted a multigenerational experiment to assess reproductive capacities regarding egg production in calanoid copepods Parvocalanus crassirostis and Acartia pacifica under different pH and temperature conditions. The experimental set-up allowed assessing the tandem effect of warming and acidification on the number of eggs produced by healthy copepod pairs under two pH conditions of 8.20 and 7.50 (hard selection) as well as with a gradual reduction of 0.05 pH units at each generation (soft selection). The results are quite interesting, with very diverse performance across temperatures. The number of eggs produced under hard selection was higher at pH 8.20 compared to pH 7.50 for both species, with the maximum number of eggs produced at 24–28 °C, whereas under soft selection, there was no significant difference in the egg production rate at 24–28 °C across generations and there was an improvement in the number of eggs produced at 8–16 °C. The results provide evidence that in a future ocean scenario of lower pH and higher temperature, the two species, and possibly the copepod population at large, might not decrease. Copepod populations might be resilient, and the transcriptomic evidence of adaptation to increased temperature and lower pH is a ray of hope. We believe further studies are needed to provide more robust datasets to underpin the hypothesis of adaptation to climate change.
Continue reading ‘The reproductive capacities of the calanoid copepods Parvocalanus crassirostis and Acartia pacifica under different pH and temperature conditions’Northern shrimp from multiple origins show similar sensitivity to global change drivers, but different cellular energetic capacity
Published 3 August 2023 Science ClosedTags: biological response, crustaceans, laboratory, mortality, multiple factors, North Pacific, physiology, respiration, temperature
Species with a wide distribution can experience regionally a wide range of environmental conditions, to which they can acclimatize or adapt. Consequently, the geographic origin of an organism can influence its responses to environmental changes, and therefore its sensitivity to combined global change drivers. This study aimed at determining the physiological responses of the northern shrimp Pandalus borealis, at different levels of biological organization and from four different geographic origins, exposed to elevated temperature and low pH to define its sensitivity to future ocean warming (OW) and acidification (OA). Shrimp sampled within the northwest Atlantic, were exposed for 30 days to combinations of three temperature (2, 6 or 10 °C) and two pH levels (7.75 or 7.40). Survival, metabolic rates, whole-organism aerobic performance and cellular energetic capacity were assessed at the end of the exposure. Our results show that shrimp survival was negatively affected by temperature above 6 °C and low pH, regardless of their origin. Additionally, shrimp from different origins show overall similar whole-organism performances: aerobic scope increasing with increasing temperature and decreasing with decreasing pH. Finally, the stability of aerobic metabolism appears to be related to cellular adjustments specific to shrimp origin. Our results show that the level of intraspecific variation differs among levels of biological organization: different cellular capacities lead to similar individual performances. Thus, the northern shrimp sensitivity to OW and OA is overall comparable among origins. Nonetheless, shrimp vulnerability to predicted global change scenarios for 2100 could differ among origins due to different regional environmental conditions.
Continue reading ‘Northern shrimp from multiple origins show similar sensitivity to global change drivers, but different cellular energetic capacity’Characteristics of meiofaunal community in the subtidal zone near Hupo, anticipating ocean acidification in the East Sea of Korea
Published 19 June 2023 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, community composition, crustaceans, field, nematodes, North Pacific, otherprocess, protists, zooplankton
This study aimed to investigate the meiofauna community characteristics in coastal waters highly affected by ocean acidification. Therefore, the meiofauna communities in the coastal waters of Hupo in Uljin-gun, a county bordering the East Sea of Korea, were monitored over five years. During the study period, the mean abundance of total meiofauna communities expressed in population density was 614.4 individuals (Inds.)/10 cm2, similar to the reported meiofauna abundance in the subtidal zone in the Yellow Sea of Korea, an area with sandy sedimentary facies. The most dominant taxa were nematodes (65–70%) and harpacticoids (7–20%); these two taxa accounted for approximately 80% of the total meiofauna abundance. Among the stations studied, station (St.) 10 showed the lowest seawater pH value, and in 2011, when the measured pH was the lowest at 7.82, St. 10 showed the lowest abundance values for total meiofauna and harpacticoids in the 5-year period. To examine the effect of ocean acidification on meiofauna communities at the species level, species of nematodes, the most dominant taxon, were analyzed. The results indicated that the number of nematode species at St. 10 in 2009, when the pH value was low, was 8, which was very low compared to that in the other years of the study period. According to the feeding type, epistrate feeders (2A) accounted for a remarkably high proportion at St. 10, which showed a low pH. This study provides various data on meiobenthic community characteristics to understand the effects of ocean acidification on coastal ecosystems.
Continue reading ‘Characteristics of meiofaunal community in the subtidal zone near Hupo, anticipating ocean acidification in the East Sea of Korea’Risk assessment of a coastal ecosystem from SW Spain exposed to CO2 enrichment conditions
Published 8 June 2023 Science ClosedTags: abundance, biogeochemistry, biological response, BRcommunity, community composition, crustaceans, echinoderms, laboratory, mesocosms, mollusks, morphology, mortality, North Atlantic, otherprocess, physiology, sediment
The Weight-of-Evidence (WOE) approach uses multiple lines of evidence to analyze the adverse effects associated with CO2 enrichment in two stations from the Gulf of Cádiz (Spain) with different contamination degrees. Sediment contamination and metal (loid) mobility, toxicity, ecological integrity, and bioaccumulation from the samples exposed to different acidification scenarios (pH gradient from 8.0 to 6.0) were used in the WOE. The experiments were conducted under laboratory conditions using a CO2-bubbling system. Different integration approaches such as multivariate analyses were used to evaluate the results. The results indicated that the adverse biological effects under pH 6.5 were related to the mobility of dissolved elements (As, Fe, Cu, Ni, and Zn). Furthermore, the pH reduction was correlated to the increase of bioaccumulation of As, Cr, Cu, Fe, and Ni in the tissues of mussels at pH 7.0. The noncontaminated sediment showed environmental degradation related to the acidification at pH values of 7.0; whereas the sediment moderately contaminated showed both environmental risks, caused by acidification and the presence and the increase of the bioavailability of contaminants. The WOE approach supposes an effective tool to identify and distinguish the causes of adverse effects related to the enrichment of CO2 in marine environments.
Continue reading ‘Risk assessment of a coastal ecosystem from SW Spain exposed to CO2 enrichment conditions’Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves
Published 5 June 2023 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, cnidaria, community composition, crustaceans, echinoderms, Indian, mollusks, otherprocess, phanerogams, phytoplankton, primary production, review, socio-economy
Highlights
- Overfishing and climate change show potential effects on MMI ES.
- MMI regulating ES can be quantified using species richness and functional traits.
- Digital platforms are valuable tools to retrieve data but have limitations.
- Baseline data and information on environmental changes and MMI ES is provided.
Abstract
This study aimed to investigate the impact of changing environmental conditions on MMI ES in seagrasses and mangroves. We used data from satellite and biodiversity platforms combined with field data to explore the links between ecosystem pressures (habitat conversion, overexploitation, climate change), conditions (environmental quality, ecosystem attributes), and MMI ES (provisioning, regulation, cultural). Both seagrass and mangrove extents increased significantly since 2016. While sea surface temperature showed no significant annual variation, sea surface partial pressure CO2, height above sea level and pH presented significant changes. Among the environmental quality variables only silicate, PO4 and phytoplankton showed significant annual varying trends. The MMI food provisioning increased significantly, indicating overexploitation that needs urgent attention. MMI regulation and cultural ES did not show significant trends overtime. Our results show that MMI ES are affected by multiple factors and their interactions can be complex and non-linear. We identified key research gaps and suggested future directions for research. We also provided relevant data that can support future ES assessments.
Continue reading ‘Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves’Effects of anthropogenic stressorson Helgoland’s lobsters(Homarus gammarus)
Published 2 June 2023 Science ClosedTags: biological response, crustaceans, laboratory, morphology, mortality, multiple factors, North Atlantic, physiology, temperature
As meroplankton, lobsters make up a great portion of both benthic communities and planktonic fauna in the water column. Furthermore, they represent a mayor food source across the marine food web and a vital source of protein for humans. As an economically important species, lobsters are highly susceptible to anthropogenic stressors (e.g habitat destruction, over-fishing, noise pollution). Moreover, climate change may magnify the impact of human activities on lobsters’ fitness. The collapse of the population of European lobster (Homarus gammarus) around Helgoland constitutes a good example and prompted a largescale restocking program. Yet, the question arises if recruitment of remaining natural individuals and program released specimens could be stunted by ongoing climate change and human activities.
In my thesis I investigate the effect of several anthropogenic stressors that could potentially be affecting the route to recovery of Helgoland’s lobsters.
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Owing to the difficulties in catching lobster larvae in the field, I used larvae from lobster-rearing facilities to study the effects of anthropogenic stress on larval development and physiology. Studies on the effects of climate change on European lobster larvae have mostly focused on the isolated effect of ocean acidification or warming. Acidification treatments were based on two shared socio-economic pathways emitted by the Intergovernmental Panel on Climate Change (IPCC) regarding the amount of atmospheric CO2 for the end of the century. This study is the first to provide a more complete picture of the thermal limits at different levels of biological organization of lobster larvae under acidification by including a ten-level temperature gradient setup (13-24°C) The results show temperature was positively correlated with growth and energy metabolism; while, pCO2 had a negative impact on survival and morphology. Thus, climate change could potentially stunt the European lobster restocking efforts taking place on the island.
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Continue reading ‘Effects of anthropogenic stressorson Helgoland’s lobsters(Homarus gammarus)’The Paleocene-Eocene transition in the Gulf of Guinea: evidence of the Petm in the Douala Basin, Cameroon
Published 1 June 2023 Science ClosedTags: biological response, crustaceans, dissolution, field, morphology, North Atlantic, paleo, protists, sediment
The Paleocene-Eocene Thermal Maximum (PETM) was identified for the first time in two sections (Bongue and Dibamba) from the Douala sub-basin located in the Gulf of Guinea, Cameroon. This discovery was based on a multi-disciplinary approach including benthic and planktic foraminifera, ostracods, major and trace elements, mercury, carbon stable isotope (δ13C values), total organic carbon (TOC), whole-rock and clay mineralogy. A combination of lithology, microfossil assemblage, and carbon isotope data indicate zone P5 and the top of the Paleocene enabling the definition of the Paleocene-Eocene boundary (PEB). A negative carbon-isotope excursion (CIE) spanning from the uppermost Paleocene deposits to the earliest Eocene sediments (PETM interval) shows a shift in δ13Corg values of 1.5 ‰ in Bongue and 3.0 ‰ in Dibamba. In both sections, this interval is affected by widespread acidification, as revealed by carbonate dissolution and microfossil preservation (i.e., species are dwarfed, broken, thin shelled, and with holes). The very low carbonate content and the scarcity of microfauna indicate the severity of acidification during the PETM, especially in the early Eocene where only one species was identified (Igorina broedermanni). Mercury anomalies, TOC contents, and trace element concentration ratios, point to volcanic activity linked to the Cameroon Volcanic Line (CVL) intrusive magma, and a decrease in productivity prior to the PETM. In addition to climate change, our geochemical and mineralogical data support the hypothesis that other environmental perturbations such as an increase in productivity and detrital input, as well as a decrease in bottom water oxygenation occurred during the PETM in the Douala sub-basin.
Continue reading ‘The Paleocene-Eocene transition in the Gulf of Guinea: evidence of the Petm in the Douala Basin, Cameroon’Ocean acidification increases inorganic carbon over organic carbon in shrimp’s exoskeleton
Published 23 May 2023 Science ClosedTags: biogeochemistry, biological response, calcification, crustaceans, laboratory, morphology, respiration
Highlights
- PIC: POC ratio in shrimps’ exoskeleton may increase under future OA.
- Hyper-calcification and increased respiration are possible in shrimps under OA releasing more CO2 into the water.
- Increased PIC: POC ratio may impact the ecosystem functions as well as the carbon cycle.
Abstract
Ocean acidification (OA) may either increase or have a neutral effect on the calcification in shrimp’s exoskeleton. However, investigations on changes in the carbon composition of shrimp’s exoskeletons under OA are lacking. We exposed juvenile Pacific white shrimps to target pHs of 8.0, 7.9, and 7.6 for 100 days to evaluate changes in carapace thickness, total carbon (TC), particulate organic carbon (POC), particulate inorganic carbon (PIC), calcium, and magnesium concentrations in their exoskeletons. The PIC: POC ratio of shrimp in pH 7.6 treatment was significantly higher by 175 % as compared to pH 8.0 treatment. Thickness and Ca% in pH 7.6 treatment were significantly higher as compared to pH 8.0 treatment (90 % and 65 %, respectively). This is the first direct evidence of an increased PIC: POC ratio in shrimp exoskeletons under OA. In the future, such changes in carbon composition may affect the shrimp population, ecosystem functions, and regional carbon cycle.
Continue reading ‘Ocean acidification increases inorganic carbon over organic carbon in shrimp’s exoskeleton’A scientometric review of climate change and research on crabs
Published 15 May 2023 Science ClosedTags: biological response, crustaceans, review
Highlights
- Analyzed 2834 articles and 107,502 cited references from the (WOSCC) database, spanning 1977 to 2022.
- Identified leading contributors, institutions, research hotspots, and frontiers in the field.
- Categorized pivotal research issues and delineated the knowledge structure pertaining to marine biodiversity.
- Explored emergent research frontiers and hotspots in marine biodiversity studies.
- Assessed the current state of research and pinpointed prospective future avenues for investigation in this domain.
Abstract
Crabs categorized as cold-blooded organisms are especially at risk as climate change worsens. Their current situation was not well documented, especially in terms of scientometric analysis. The present study aims to investigate the relationship between research on crabs and climate change-related studies, with a focus on identifying trends and hotspots over time. The analysis was based on a collection of over 2834 relevant documents and 107,502 cited references indexed in the Web of Science Core Collection (WOSCC) database from 1977 to 2022. The findings indicated an increase in research in recent decades, with the USA as the largest contributor, followed by China and Brazil. Researchers from the USA and Germany were among the top published authors in the field. The most highly cited studies in WOSCC focused on the relationship between harmful algal blooms and crab research. Of these studies, 20 clusters were generated, with the most influential cluster identified as related to “ocean acidification,” “blue king crab,” and “mud crab fishery.” The most frequently cited and influential keywords in the field were “climate change” and “hypoxia,” respectively. Our conclusion is that the fields of “research on crabs” and “climate change” are thriving and that further exploration of the adaptation strategies of these organisms is necessary. This knowledge will benefit scientific communities, philanthropic funders or related governments, fisheries-related industries, and NGOs towards the sustainable management of commercial crab species in the future.
Continue reading ‘A scientometric review of climate change and research on crabs’Ocean acidification alters foraging behaviour in Dungeness crab through impairment of the olfactory pathway
Published 12 May 2023 Science ClosedTags: biological response, crustaceans, laboratory, morphology, North Pacific, performance, physiology
Crustacean olfaction is fundamental to most aspects of living and communicating in aquatic environments and more broadly, for individual- and population-level success. Accelerated ocean acidification from elevated CO2 threatens the ability of crabs to detect and respond to important olfactory-related cues. Here, we demonstrate that the ecologically and economically important Dungeness crab (Metacarcinus magister) exhibits reduced olfactory-related antennular flicking responses to a food cue when exposed to near-future CO2 levels, adding to the growing body of evidence of impaired crab behaviour. Underlying this altered behaviour, we find that crabs have lower olfactory nerve sensitivities (twofold reduction in antennular nerve activity) in response to a food cue when exposed to elevated CO2. This suggests that near-future CO2 levels will impact the threshold of detection of food by crabs. We also show that lower olfactory nerve sensitivity in elevated CO2 is accompanied by a decrease in the olfactory sensory neuron (OSN) expression of a principal chemosensory receptor protein, ionotropic receptor 25a (IR25a) which is fundamental for odorant coding and olfactory signalling cascades. The OSNs also exhibit morphological changes in the form of decreased surface areas of their somata. This study provides the first evidence of the effects of high CO2 levels at multiple levels of biological organization in marine crabs, linking physiological and cellular changes with whole animal behavioural responses.
Continue reading ‘Ocean acidification alters foraging behaviour in Dungeness crab through impairment of the olfactory pathway’Ocean warming and CO2-driven acidification can alter the toxicity of metal-contaminated sediments to the meiofauna community
Published 8 May 2023 Science ClosedTags: abundance, biological response, BRcommunity, community composition, crustaceans, laboratory, mesocosms, metals, multiple factors, nematodes, otherprocess, South Atlantic, temperature, toxicants, zooplankton
Highlights
- Contamination interacted with warming but the effect on density was taxon dependent.
- Warming increased metal effects in nematods and copepods, and decreased in acoelomorphs.
- Copepod densities were lower, and acoelomorphs higher, in the high CO2/low pH scenario.
- Global change studies should consider multispecies exposures in multi-stressor scenarios.
Abstract
Interactive effects of trace metal contamination, ocean warming, and CO2-driven acidification on the structure of a meiofaunal benthic community was assessed. Meiofauna microcosm bioassays were carried out in controlled conditions in a full factorial experimental design which included three fixed factors: metal contamination in the sediment (3 levels of a mixture of Cu, Pb, Zn, and Hg), temperature (26 and 28 °C) and pH (7.6 and 8.1). Metal contamination caused a sharp decrease in the densities of the most abundant meiobenthic groups and interacted with temperature rise, exacerbating deleterious effects for Nematoda and Copepoda, but mitigating effects for Acoelomorpha. CO2-driven acidification resulted in increased acoelomorphs density, but only in sediments with lower levels of metals. Copepod densities, in turn, were lower in the CO2-driven acidification scenario regardless of contamination or temperature. The results obtained in the present study showed that temperature rise and CO2-driven acidification of coastal ocean waters, at environmentally relevant levels, interacts with trace metals in marine sediments, differently affecting the major groups of benthic biota.
Continue reading ‘Ocean warming and CO2-driven acidification can alter the toxicity of metal-contaminated sediments to the meiofauna community’Acid times in physiology: a systematic review of the effects of ocean acidification on calcifying invertebrates
Published 5 May 2023 Science ClosedTags: biological response, calcification, corals, crustaceans, echinoderms, growth, mollusks, mortality, physiology, review
The reduction in seawater pH from rising levels of carbon dioxide (CO2) in the oceans has been recognized as an important force shaping the future of marine ecosystems. Therefore, numerous studies have reported the effects of ocean acidification (OA) in different compartments of important animal groups, based on field and/or laboratory observations. Calcifying invertebrates have received considerable attention in recent years. In the present systematic review, we have summarized the physiological responses to OA in coral, echinoderm, mollusk, and crustacean species exposed to predicted ocean acidification conditions in the near future. The Scopus, Web of Science, and PubMed databases were used for the literature search, and 75 articles were obtained based on the inclusion criteria. Six main physiological responses have been reported after exposure to low pH. Growth (21.6%), metabolism (20.8%), and acid-base balance (17.6%) were the most frequent among the phyla, while calcification and growth were the physiological responses most affected by OA (>40%). Studies show that the reduction of pH in the aquatic environment, in general, supports the maintenance of metabolic parameters in invertebrates, with redistribution of energy to biological functions, generating limitations to calcification, which can have severe consequences for the health and survival of these organisms. It should be noted that the OA results are variable, with inter and/or intraspecific differences. In summary, this systematic review offers important scientific evidence for establishing paradigms in the physiology of climate change in addition to gathering valuable information on the subject and future research perspectives.
Continue reading ‘Acid times in physiology: a systematic review of the effects of ocean acidification on calcifying invertebrates’Adult snow crab, Chionoecetes opilio, display body-wide exoskeletal resistance to the effects of long-term ocean acidification
Published 27 April 2023 Science ClosedTags: biological response, crustaceans, laboratory, morphology, North Pacific, physiology
Structural and mechanical properties of the decapod exoskeleton affect foraging, defense, and locomotion. Ocean acidification (OA) poses a threat to marine biomes and their inhabitants, particularly calcifying organisms. Vulnerability of the snow crab, Chionecetes opilio, a commercially important, high-latitude species, to OA has not been explored. Although all oceans are experiencing acidification, abiotic factors in high-latitude areas increase the rate of acidification. We examined the effect of long-term (2 year) exposure to decreased seawater pH (7.8 and 7.5, PCO2 ~ 760 and 1550 µatm, respectively) on exoskeletal properties in post-terminal-molt female C. opilio. Since the effects of OA vary among body regions in decapods, exoskeletal properties (microhardness, thickness, and elemental composition) were measured in five body regions: the carapace, both claws, and both third walking legs. Overall, adult C. opilio exoskeletons were robust to OA in all body regions. Decreased pH had no effect on microhardness or thickness of the exoskeleton, despite a slight (~ 6%) reduction in calcium content in crabs held at pH 7.5. In contrast, exoskeletal properties varied dramatically among body regions regardless of pH. The exoskeleton of the claws was harder, thicker, and contained more calcium but less magnesium than that of other body regions. Exoskeleton of the legs was thinner than that of other body regions and contained significantly greater magnesium concentrations (~ 2.5 times higher than the claws). Maintenance of exoskeletal properties after long-term OA exposure, at least down to pH 7.5, in adult C. opilio suggests that wild populations may tolerate future ocean pH conditions.
Continue reading ‘Adult snow crab, Chionoecetes opilio, display body-wide exoskeletal resistance to the effects of long-term ocean acidification’Hypoxia tolerance, but not low pH tolerance, is associated with a latitudinal cline across populations of Tigriopus californicus
Published 6 April 2023 Science ClosedTags: adaptation, biological response, crustaceans, field, laboratory, morphology, mortality, multiple factors, North Pacific, otherprocess, oxygen, zooplankton
Intertidal organisms must tolerate daily fluctuations in environmental parameters, and repeated exposure to co-occurring conditions may result in tolerance to multiple stressors correlating. The intertidal copepod Tigriopus californicus experiences diurnal variation in dissolved oxygen levels and pH as the opposing processes of photosynthesis and cellular respiration lead to coordinated highs during the day and lows at night. While environmental parameters with overlapping spatial gradients frequently result in correlated traits, less attention has been given to exploring temporally correlated stressors. We investigated whether hypoxia tolerance correlates with low pH tolerance by separately testing the hypoxia and low pH stress tolerance separately of 6 genetically differentiated populations of T. californicus. We independently checked for similarities in tolerance for each of the two stressors by latitude, sex, size, and time since collection as predictors. We found that although hypoxia tolerance correlated with latitude, low pH tolerance did not, and no predictor was significant for both stressors. We concluded that temporally coordinated exposure to low pH and low oxygen did not result in populations developing equivalent tolerance for both. Although climate change alters several environmental variables simultaneously, organisms’ abilities to tolerate these changes may not be similarly coupled.
Continue reading ‘Hypoxia tolerance, but not low pH tolerance, is associated with a latitudinal cline across populations of Tigriopus californicus’Review of warming and acidification effects to the ecotoxicity of pharmaceuticals on aquatic organisms in the era of climate change
Published 6 April 2023 Science ClosedTags: biological response, crustaceans, fish, metals, molecular biology, mollusks, mortality, multiple factors, physiology, respiration, review, temperature, toxicants
Highlights
- Acidification and warming modulates the ecotoxicity of pharmaceuticals.
- Biochemical, cellular and behavioral biomarkers show a response.
- Trends of change in acute and chronic toxicity were drug dependent.
- Acidification modified the toxicity of selected ionizable pharmaceuticals.
- Bioaccumulation was modified by target effects of global warming.
Abstract
An increase in the temperature and the acidification of the aquatic environment are among the many consequences of global warming. Climate change can also negatively affect aquatic organisms indirectly, by altering the toxicity of pollutants. Models of climate change impacts on the distribution, fate and ecotoxicity of persistent pollutants are now available. For pharmaceuticals, however, as new environmental pollutants, there are no predictions on this issue. Therefore, this paper organizes the existing knowledge on the effects of temperature, pH and both stressors combined on the toxicity of pharmaceuticals on aquatic organisms. Besides lethal toxicity, the molecular, physiological and behavioral biomarkers of sub-lethal stress were also assessed. Both acute and chronic toxicity, as well as bioaccumulation, were found to be affected. The direction and magnitude of these changes depend on the specific pharmaceutical, as well as the organism and conditions involved. Unfortunately, the response of organisms was enhanced by combined stressors. We compare the findings with those known for persistent organic pollutants, for which the pH has a relatively low effect on toxicity. The acid-base constant of molecules, as assumed, have an effect on the toxicity change with pH modulation. Studies with bivalves have been were overrepresented, while too little attention was paid to producers. Furthermore, the limited number of pharmaceuticals have been tested, and metabolites skipped altogether. Generally, the effects of warming and acidification were rather indicated than explored, and much more attention needs to be given to the ecotoxicology of pharmaceuticals in climate change conditions.
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