Ecosystem functioning depends on complex interactions between microorganisms, hosts, and the environment. Changes in environmental conditions (e.g., ocean acidification) in combination with anthropogenic pollution have been shown to affect the composition and function of free-living microbial communities, but little is known about the effects these stressors on host-associated communities. This study aims to characterize the response of host-associated bacterial communities of the bottom-dwelling polychaete Hediste diversicolor and the epibenthic gastropod Peringia ulvae to oil contamination and reduced seawater pH. The independent and interactive effects of both stressors were simulated under controlled conditions. The response of host-associated bacterial communities was assessed using the high-throughput sequencing of the 16S rRNA gene and several biochemical markers related to host metabolic pathways, e.g., neurotransmission, anaerobic metabolism, biotransformation, oxidative stress, and energy consumption. In H. diversicolor, reduced seawater pH was associated with a high relative abundance of Cyanobacteria, while in P. ulvae oil contamination was associated with a reduction in the relative abundance of Chitinophagales. In P. ulvae, enrichment with oil hydrocarbon-degrading bacteria suggests a possible role of these organisms in the dispersion of oil hydrocarbon degraders. Furthermore, oil supplementation shifted some specific biochemical markers of gastropods related to oxidative stress and energy consumption, which suggests host stress. In general, the bacterial communities and biochemical markers of the gastropod were more affected by stressors than those of the polychaete. Overall, this study contributes to a better understanding of the response of host-associated bacterial communities of benthic macrofauna to anthropogenic contamination and environmental change.
Continue reading ‘Effects of reduced seawater pH and oil contamination on bacterial communities and biochemical markers of estuarine animal hosts’Posts Tagged 'performance'
Effects of reduced seawater pH and oil contamination on bacterial communities and biochemical markers of estuarine animal hosts
Published 18 March 2024 Science ClosedTags: annelids, biological response, chemistry, community composition, laboratory, molecular biology, mollusks, mortality, North Atlantic, otherprocess, performance, physiology, toxicants
Ocean acidification impact on the uptake of trace elements by mussels and their biochemical effects
Published 13 March 2024 Science ClosedTags: biological response, chemistry, laboratory, metals, mollusks, morphology, multiple factors, North Atlantic, performance, physiology
Highlights
- Copper and cerium bioavailability may increase under ocean acidification.
- Ocean acidification impacts metal accumulation in mussel gills.
- Biochemical responses in M. galloprovincialis altered by trace metals and OA.
- Complex interplay of oxidative stress markers affected by OA and metals.
Abstract
This study delves into the intricate interplay between ocean acidification (OA), metal bioaccumulation, and cellular responses using mussels (Mytilus galloprovincialis) as bioindicators. For this purpose, environmentally realistic concentrations of isotopically labelled metals (Cd, Cu, Ag, Ce) were added to investigate whether the OA increase would modify metal bioaccumulation and induce adverse effects at the cellular level. The study reveals that while certain elements like Cd and Ag might remain unaffected by OA, the bioavailability of Cu and Ce could potentially escalate, leading to amplified accumulation in marine organisms. The present findings highlight a significant rise in Ce concentrations within different mussel organs under elevated pCO2 conditions, accompanied by an increased isotopic fractionation of Ce (140/142Ce), suggesting a heightened potential for metal accumulation under OA. The results suggested that OA influenced metal accumulation in the gills of mussels. Conversely, metal accumulation in the digestive gland was unaffected by OA. The exposure to both trace metals and OA affects the biochemical responses of M. galloprovincialis, leading to increased metabolic capacity, changes in energy reserves, and alterations in oxidative stress markers, but the specific effects on other biomarkers (e.g., lipid peroxidation, some enzymatic responses or acetylcholinesterase activity) were not uniform, suggesting complex interactions between the stressors and the biochemical pathways in the mussels.
Continue reading ‘Ocean acidification impact on the uptake of trace elements by mussels and their biochemical effects’Quantifying the impacts of multiple stressors on the production of marine benthic resources
Published 11 March 2024 Science ClosedTags: abundance, algae, biogeochemistry, biological response, BRcommunity, chemistry, communityMF, laboratory, mesocosms, methods, modeling, mollusks, morphology, mortality, multiple factors, North Atlantic, nutrients, otherprocess, performance, physiology, regionalmodeling, temperature
Coastal ecosystems are among the most heavily affected by climate change and anthropogenic activities, which impacts their diversity, productivity and functioning and puts many of the key ecosystem services that they provide at risk. Although empirical studies have moved beyond single-stressor-single-species experiments with limited extrapolation potential and have increasingly investigated the cumulative effects of simultaneously occurring multiple stressors, consistent generalities have not yet been identified. Upscaling from controlled experiments to natural ecosystems, therefore, remains an unsolved challenge. Disentangling the independent and cumulative effects of multiple stressors across different levels of biological complexity, revealing the underlying mechanisms and understanding how coastal ecosystems may respond to predicted scenarios of global change is critical to manage and protect our natural capital.
In this thesis, I advance multiple stressor research by applying complementary approaches to quantify the impact of multiple stressors on marine benthic resources and thereby help predict the consequences of expected climate change for coastal habitats. First, I present the newly developed experimental platform QIMS (Quantifying the Impacts of Multiple Stressors) that overcomes some of the shortfalls of previous multiple stressor research (Chapter 2). Second, in a novel empirical study, I investigate the independent and combined effects of moderate ocean warming and acidification on the functioning and production of mussels and algae, considering the effects of interspecific interactions in the presence or absence of the respective other species (Chapter 3). Third, I synthesise monitoring data from Dublin Bay (representative of a typical metropolitan estuary) using conditional interference and a Bayesian Network model and provide alternative system trajectories according to different climate change scenarios. From this new model, I deepen the understanding of the complex linkages between environmental conditions and the diversity and functioning of Dublin Bay to support local decision making and management (Chapter 4).
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Continue reading ‘Quantifying the impacts of multiple stressors on the production of marine benthic resources’Ocean acidification and food availability impacts on the metabolism and grazing in a cosmopolitan herbivorous protist Oxyrrhis marina
Published 8 March 2024 Science ClosedTags: abundance, biological response, growth, laboratory, multiple factors, North Pacific, nutrients, otherprocess, performance, physiology, primary production, protists, respiration, zooplankton
The heterotrophic dinoflagellate Oxyrrhis marina is an essential microzooplankton in coastal waters, linking the energy transfer from phytoplankton to higher trophic levels. It is of general significance to investigate how it responds and acclimates to ocean acidification (OA), especially under varied availabilities of food. Here, O. marina was exposed and acclimated to three pCO2 levels (LC: 415, MC:1000, HC:1500 μatm) for 60 days, and then was further grown under the CO2 levels with different levels of food (the microalgae Dunaliella salina) availability for about 8 generations. The OA treatments did not significantly hamper its growth and ingestion rates even under the reduced food availability and starvation (deprived of the microalgae), which significantly reduced its growth rate. While the impacts of OA on the growth and ingestion rates of O. marina were insignificant, the OA treatments appeared to have resulted in a faster decline of the heterotrophic dinoflagellate cells during the starvation period. Nevertheless, the acidic stress under the elevated pCO2 of 1000 or 1500 μatm decreased its respiration by about 53% or 59% with the high and by about 26% or 23% with the low food availability, respectively. Such OA-repressed respiration was also significant during the starvation period. On the other hand, the OA treatments and deprivation of the microalgae synergistically reduced the cellular quota of particulate organic C, N and P, resulting in a reduction of food value of the heterotrophic dinoflagellate as prey. In conclusion, our results show that O. marina is highly resilient to future ocean acidification by reducing its respiration and sustaining its ingestion of microalgae.
Continue reading ‘Ocean acidification and food availability impacts on the metabolism and grazing in a cosmopolitan herbivorous protist Oxyrrhis marina’Critical swimming speed of juvenile rockfishes (Sebastes) following long- and short-term exposures to acidification and deoxygenation
Published 6 March 2024 Science ClosedTags: biological response, fish, laboratory, multiple factors, North Pacific, oxygen, performance
Highlights
- Swimming ability of juvenile rockfishes declined during acute and chronic exposure to deoxygenation and acidification.
- Critical swimming speed of juvenile rockfish was more sensitive to deoxygenation than to acidification.
- The effects of acidified and deoxygenated conditions on juvenile rockfish swimming ability manifest rapidly (hours to days).
- Swimming performance of juvenile rockfish recovered after upwelling-event acidified/deoxygenated conditions had subsided.
- Despite early life history differences, black and copper rockfish had similar sensitivity to acidification and deoxygenation.
Abstract
Reef fishes in the California Current Ecosystem have evolved in habitats affected by seasonally variable, episodic upwelling of high pCO2 (acidified, low pH) and low dissolved oxygen (deoxygenated) water, which suggests that these fishes might exhibit resilience to ocean acidification (OA) and deoxygenation. Yet, how the fitness of these fish are affected by natural variability in pH and DO over short time scales remains poorly understood, as do the effects of longer-term trends in pH and DO driven by climate change. We conducted a complementary suite of experiments to study the effects of acidification and deoxygenation on the critical swimming speed (Ucrit) of juvenile copper (Sebastes caurinus) and black (S. melanops) rockfish collected from nearshore habitats in an ocean acidification “hotspot” off Northern California. We consistently observed that Ucrit declined more strongly in response to deoxygenation than to acidification, at least under ranges of these stressors consistent with current conditions and plausible future scenarios, and that reduction in swimming performance reflected additive rather than synergistic responses to concurrent exposure. Reductions in swimming performance manifested quickly–on the scale of hours–in response to exposure to elevated pCO2/reduced DO, yet are reversible: swimming performance of juvenile rockfish recovers within a matter of days, and perhaps much more quickly, after acidified/deoxygenated conditions have subsided. Insights from this study address potential effects of variability in upwelling intensity at event and seasonal scales for nearshore rockfishes and contribute to our understanding of fish responses to future ocean conditions driven by ongoing climate change.
Continue reading ‘Critical swimming speed of juvenile rockfishes (Sebastes) following long- and short-term exposures to acidification and deoxygenation’Behavioral responses of intertidal clams to compound extreme weather and climate events
Published 29 February 2024 Science ClosedTags: biological response, laboratory, mollusks, North Pacific, performance
Highlights
- Impacts of extreme weather and climate events on clam behaviors were examined.
- Behavioral impacts of atmospheric heatwaves can surpass those of acidification.
- Behavioral impairment was observed when heatwaves occurred initially.
- Rapid behavioral acclimation to recurrent heatwaves was evident.
Abstract
Rapidly increasing concentration of carbon dioxide (CO2) in the atmosphere not only results in global warming, but also drives increasing seawater acidification. Infaunal bivalves play critical roles in benthic-pelagic coupling, but little is known about their behavioral responses to compound climate events. Here, we tested how heatwaves and acidification affected the behavior of Manila clams (Ruditapes philippinarum). Under acidified conditions, the clams remained capable of burrowing into sediments. Yet, when heatwaves attacked, significant decreases in burrowing ability occurred. Following two consecutive events of heatwaves, the clams exhibited rapid behavioral acclimation. The present study showed that the behavior of R. philippinarum is more sensitive to heatwaves than acidification. Given that the behavior can act as an early and sensitive indicator of the fitness of intertidal bivalves, whether, and to what extent, behavioral acclimation can persist under scenarios of intensifying heatwaves in the context of ocean acidification deserve further investigations.
Continue reading ‘Behavioral responses of intertidal clams to compound extreme weather and climate events’Seasonal resilience of temperate estuarine fish in response to climate change
Published 31 January 2024 Science ClosedTags: biological response, BRcommunity, community composition, fish, modeling, North Pacific, otherprocess, performance, regionalmodeling
Highlights
- The suitability of fish habitat is threatened by falling pH, especially in spring.
- Seasonality provides resilience against climate change for estuarine fish and assemblages.
- Centroids respond by shifting northeast in spring and southeast in autumn.
- Support for estuary ecosystem management under climate change is offered.
Abstract
To date, the intricacies and efficacy of how periodic seasonal environmental fluctuations affect fish populations in biogeography in the context of profound climate change remain to be elucidated. Collected monitoring data on fish resources in the temperate estuary provide an excellent opportunity to assess the effects of seasonal environmental fluctuations on populations and functional assemblages under climate change. We first developed a framework for predicting habitat suitability under different climate change scenarios (SSP1-2.6 and SSP5-8.5) for 12 fish populations in the Yangtze estuary by examining the seasonal environmental affinities of temperate estuarine fishes. We then summarized the multidimensional habitat suitability responses (HSRs) of populations and functional assemblages and discussed the possible drivers and mechanisms underlying these changes. The results suggest that the acidity of the Yangtze estuary may decline in the future as the climate warms, endangering the ecosystem that many fish species depend on. Prospective climate change may have an impact on fish population HSRs through redistribution, area changes, and centroid migration of suitable habitats; nevertheless, affinity for environmental factors may be limited to distinguishing patterns of population response in the spring. Fish (5 populations) and functional assemblages (11 assemblages) may exhibit robust adaptations or non-adaptations to climate change when seasons change, given their suitable habitat area. Furthermore, projections indicate that the majority of fish habitat centroids exhibit seasonal responses, migrating northeast in the spring and southeast in the autumn. By decentralizing climate risk to seasonal scales, seasonal resilience in the multidimensional HSRs of several fish populations (5/12) and their functional assemblages (11/16) is revealed for the first time. Efforts to mitigate climate risks and safeguard resources should take these seasonal forecasts and indicative information into account.
Continue reading ‘Seasonal resilience of temperate estuarine fish in response to climate change’Transcriptomics, proteomics, and physiological assays reveal immunosuppression in the eastern oyster Crassostrea virginica exposed to acidification stress
Published 30 January 2024 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, mortality, multiple factors, North Atlantic, pathogens, performance, physiology
Ocean acidification (OA) is recognized as a major stressor for a broad range of marine organisms, particularly shell-building invertebrates. OA can cause alterations in various physiological processes such as growth and metabolism, although its effect on host-pathogen interactions remains largely unexplored. In this study, we used transcriptomics, proteomics, and physiological assays to evaluate changes in immunity of the eastern oyster Crassostrea virginica exposed to OA conditions (pH = 7.5 vs pH = 7.9) at various life stages. The susceptibility of oyster larvae to Vibrio infection increased significantly (131 % increase in mortality) under OA conditions, and was associated with significant changes in their transcriptomes. The significantly higher mortality of larvae exposed to pathogens and acidification stress could be the outcome of an increased metabolic demand to cope with acidification stress (as seen by upregulation of metabolic genes) at the cost of immune function (downregulation of immune genes). While larvae were particularly vulnerable, juveniles appeared more robust to the stressors and there were no differences in mortality after pathogen (Aliiroseovarius crassostrea and Vibrio spp.) exposure. Proteomic investigations in adult oysters revealed that acidification stress resulted in a significant downregulation of mucosal immune proteins including those involved in pathogen recognition and microbe neutralization, suggesting weakened mucosal immunity. Hemocyte function in adults was also impaired by high pCO2, with a marked reduction in phagocytosis (67 % decrease in phagocytosis) in OA conditions. Together, results suggest that OA impairs immune function in the eastern oyster making them more susceptible to pathogen-induced mortality outbreaks. Understanding the effect of multiple stressors such as OA and disease is important for accurate predictions of how oysters will respond to future climate regimes.
Continue reading ‘Transcriptomics, proteomics, and physiological assays reveal immunosuppression in the eastern oyster Crassostrea virginica exposed to acidification stress’Assessment of warm-water coral reef tipping point thresholds
Published 29 January 2024 Science ClosedTags: biological response, corals, performance, review
Warm-water coral reefs are facing unprecedented Anthropogenic driven threats to their continued existence as biodiverse, functional ecosystems upon which hundreds of millions of people rely. Determining the tipping point thresholds of coral reef ecosystems requires robust assessment of multiple stressors and their interactive effects. We draw upon a literature search and the recent Global Tipping Points Revision initiative to consider warm-water coral reef ecosystem tipping point threshold sensitivity. Considering observed and projected stressor impacts we recognise a global mean surface temperature (relative to pre-industrial) tipping point threshold of 1.2 °C (range 0.7–1.5 °C) and an atmospheric CO2 warming threshold of 350 ppm (range 326–400 ppm), whilst acknowledging that interacting stressors, ocean warming response time, overshoot and cascading impacts have yet to be sufficiently assessed but are likely to lower this threshold. These uncertainties around tipping point sensitivities for such a crucially important ecosystem underlines the imperative of robust assessment and, in the case of knowledge gaps, employing a precautionary principle favouring the lower range tipping point values.
Continue reading ‘Assessment of warm-water coral reef tipping point thresholds’Season influences interspecific responses of canopy-forming kelps to future warming and acidification at high latitude
Published 26 January 2024 Science ClosedTags: algae, biological response, growth, laboratory, morphology, multiple factors, North Pacific, performance, physiology, temperature
Variability in primary producers’ responses to environmental change may buffer higher trophic levels against shifts in basal resource composition. Then again, in instances where there is a lack of functional redundancy because consumers rely on a few species to meet their energetic requirements at specific times of the year, altered community production dynamics may significantly impact food web resilience. In high-latitude kelp forests, a complementary annual phenology of seaweed production supports coastal marine consumers’ metabolic needs across large seasonal variations in their environment. Yet, marine consumers in these systems may face significant metabolic stress under the pronounced low pH conditions expected in future winters, particularly if they lack the resources to support their increased energetic demands. In this study, we investigate how the growth and nutritional value of three dominant, coexisting macroalgal species found in subpolar kelp forests will respond to ocean acidification and warming in future winter and summer seasons. We find that the three kelps Macrocystis pyrifera, Hedophyllum nigripes, and Neoagarum fimbriatum differ in their vulnerability to future environmental conditions, and that the seasonal environmental context of nutrient and light availability shapes these responses. Our results suggest that poleward fringe populations of M. pyrifera may be relatively resilient to anticipated ocean warming and acidification. In contrast, ocean warming conditions caused a decrease in the biomass and nutritional quality of both understory kelps. Considering the unique production phenology of H. nigripes, we emphasize that negative impacts on this species in future winters may be of consequence to consumer energetics in this system. This work highlights how interspecific variation in autotrophs’ responses to global change can disrupt the diversity and phenological structure of energy supply available to higher trophic levels.
Continue reading ‘Season influences interspecific responses of canopy-forming kelps to future warming and acidification at high latitude’The combined effects of acidification and acute warming on the embryos of Pacific herring (Clupea pallasii)
Published 26 January 2024 Science ClosedTags: biological response, fish, laboratory, mortality, multiple factors, North Pacific, performance, physiology, reproduction, respiration, temperature
Anthropogenic climate change is projected to affect marine ecosystems by challenging the environmental tolerance of individuals. Marine fishes may be particularly vulnerable to emergent climate stressors during early life stages. Here we focus on embryos of Pacific herring (Clupea pallasii), an important forage fish species widely distributed across the North Pacific. Embryos were reared under a range of temperatures (10-16°C) crossed with two pCO2 levels (600 and 2000 μatm) to investigate effects on metabolism and survival. We further tested how elevated pCO2 affects critical thermal tolerance (CTmax) by challenging embryos to short-term temperature fluctuations. Experiments were repeated on embryos collected from winter and spring spawning populations to determine if spawning phenology corresponds with different limits of environmental tolerance in offspring. We found that embryos could withstand acute exposure to 20°C regardless of spawning population or incubation treatment, but that survival was greatly reduced after 2-3 hours at 25°C. We found that pCO2 had limited effects on CTmax. The survival of embryos reared under chronically warm conditions (12°, 14°, or 16°C) was significantly lower relative to 10°C treatments in both populations. Oxygen consumption rates (MO2) were also higher at elevated temperatures and pCO2 levels. However, heart contraction measurements made 48 hours after CTmax exposure revealed a greater increase in heart rate in embryos reared at 10°C compared to 16°C, suggesting acclimation at higher incubation temperatures. Our results indicate that Pacific herring are generally tolerant of pCO2 but are vulnerable to acute temperature stress. Importantly, spring-spawning embryos did not clearly exhibit a higher tolerance to heat stress compared to winter offspring.
Continue reading ‘The combined effects of acidification and acute warming on the embryos of Pacific herring (Clupea pallasii)’The vulnerability of World Heritage seagrass habitats to climate change
Published 23 January 2024 Science ClosedTags: adaptation, biological response, otherprocess, performance, phanerogams
Seagrass is an important natural attribute of 28 World Heritage (WH) properties. These WH seagrass habitats provide a wide range of services to adjacent ecosystems and human communities, and are one of the largest natural carbon sinks on the planet. Climate change is considered the greatest and fastest-growing threat to natural WH properties and evidence of climate-related impacts on seagrass habitats has been growing. The main objective of this study was to assess the vulnerability of WH seagrass habitats to location-specific key climate stressors. Quantitative surveys of seagrass experts and site managers were used to assess exposure, sensitivity and adaptive capacity of WH seagrass habitats to climate stressors, following the Climate Vulnerability Index approach. Over half of WH seagrass habitats have high vulnerability to climate change, mainly from the long-term increase in sea-surface temperature and short-term marine heatwaves. Potential impacts from climate change and certainty scores associated with them were higher than reported by a similar survey-based study from 10 years prior, indicating a shift in stakeholder perspectives during the past decade. Additionally, seagrass experts’ opinions on the cumulative impacts of climate and direct-anthropogenic stressors revealed that high temperature in combination with high suspended sediments, eutrophication and hypoxia is likely to provoke a synergistic cumulative (negative) impact (p < .05). A key component contributing to the high vulnerability assessments was the low adaptive capacity; however, discrepancies between adaptive capacity scores and qualitative responses suggest that managers of WH seagrass habitats might not be adequately equipped to respond to climate change impacts. This thematic assessment provides valuable information to help prioritize conservation actions, monitoring activities and research in WH seagrass habitats. It also demonstrates the utility of a systematic framework to evaluate the vulnerability of thematic groups of protected areas that share a specific attribute.
Continue reading ‘The vulnerability of World Heritage seagrass habitats to climate change’Biochemical adaptability of the relationship between tropical hard corals and photosynthetic symbiotic algae under climate change
Published 23 January 2024 Science ClosedTags: adaptation, algae, BRcommunity, corals, otherprocess, performance, review
Tropical coral reefs, a vital component of the global marine ecosystem, are currently under threat from climate change factors such as rising temperatures, ocean acidification, and extreme weather events. High temperatures induce coral bleaching, resulting in the loss of their energy supply and an acceleration of metabolic rates, rendering them more vulnerable. Ocean acidification affects the formation of calcium carbonate skeletons in symbiotic algae and decreases photosynthetic efficiency, further exacerbating the risk of damage to the symbiotic algae in high-temperature conditions. Extreme weather events directly cause physical damage to corals and alter marine environments, reducing their chances of survival. This review focuses on the impact of climate change on the biochemical adaptability between tropical hard corals and photosynthetic symbiotic algae, exploring their ecological relationship, the influence of climate change on this relationship, and the adaptive mechanisms. Understanding the adaptive mechanisms between hard corals and symbiotic algae is crucial for developing conservation strategies and management plans to maintain the functionality and biodiversity of coral reef ecosystems. It also aids in ensuring the survival and prosperity of this delicate relationship under the challenges posed by climate change, allowing future generations to continue enjoying the magnificence of tropical coral reefs.
Continue reading ‘Biochemical adaptability of the relationship between tropical hard corals and photosynthetic symbiotic algae under climate change ‘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.
A comprehensive review of the effects of salinity, dissolved organic carbon, pH, and temperature on copper biotoxicity: implications for setting the copper marine water quality criteria
Published 18 January 2024 Science ClosedTags: biological response, performance, physiology, review
Highlights
- Salinity, DOC, pH and temperature will significantly influence copper toxicity.
- DOC is the most studied factor in the establishment of Cu WQCs in seawater.
- Cu WQC values were primarily determined using BLM, WER, QSAR and regression models.
- Salinity, DOC and temperature should be considered in determining the Cu marine WQCs.
Abstract
In recent years, there has been a growing concern about the ecological hazards associated with copper, which has sparked increased interest in copper water quality criteria (WQC). The crucial factors affecting the bioavailability of copper in seawater are now acknowledged to be salinity, dissolved organic carbon (DOC), pH, and temperature. Research on the influence of these four water quality parameters on copper toxicity is rapidly expanding. However, a comprehensive and clear understanding of the relevant mechanisms is currently lacking, hindering the development of a consistent international method to establish the seawater WQC value for copper. As a response to this knowledge gap, this study presents a comprehensive summary with two key focuses: (1) It meticulously analyzes the effects of salinity, DOC, pH, and temperature on copper toxicity to marine organisms. It takes into account the adaptability of different species to salinity, pH and temperature. (2) Additionally, the study delves into the impact of these four water parameters on the acute toxicity values of copper on marine organisms while also reviewing the methods used in establishing the marine WQC value of copper. The study proposed a two-step process: initially zoning based on the difference of salinity and DOC, followed by the establishment of Cu WQC values for different zones during various seasons, considering the impacts of water quality parameters on copper toxicity. By providing fundamental scientific insights, this research not only enhances our understanding and predictive capabilities concerning water quality parameter-dependent Cu toxicity in marine organisms but also contributes to the development of copper seawater WQC values. Ultimately, this valuable information facilitates more informed decision-making in marine water quality management efforts.
Continue reading ‘A comprehensive review of the effects of salinity, dissolved organic carbon, pH, and temperature on copper biotoxicity: implications for setting the copper marine water quality criteria’Sometimes (often?) responses to multiple stressors can be predicted from single-stressor effects: a case study using an agent-based population model of croaker in the Gulf of Mexico
Published 18 January 2024 Science ClosedTags: abundance, biological response, BRcommunity, communitymodeling, fish, individualmodeling, modeling, morphology, mortality, multiple factors, North Atlantic, otherprocess, oxygen, performance, reproduction, temperature
Abstract
Objective
Rapid changes in the world’s oceans make assessment of fish population responses to multiple stressors, especially on scales relevant to management, increasingly important. I used an existing agent-based, spatially explicit model of Atlantic Croaker Micropogonias undulatus in the northern Gulf of Mexico to examine how temperature, hypoxia, and ocean acidification, singly and in combinations, affect long-term population dynamics.
Methods
I performed a factorial simulation experiment with each stressor at three levels and analyzed various treatment combinations to assess the additivity and multiplicity of interactions. The response variables were long-term equilibrium (final year) values of spawning stock biomass (SSB), recruitment, weight at age, and two measures of stock productivity (recruits per SSB and maximum recruitment) derived from the spawner–recruit relationship fitted to model output. I used the single-stressor effects from the experiment to predict how the response variables would change when all three stressors were changed. Single-stressor effects were combined as the sum of the fractional changes (additive scale) and the product of ratios of changes (multiplicative scale) and compared to the responses in simulations with all stressors imposed.
Result
Analyzing the factorial design for two-way and three-way interactions showed that there were many interactions on the additive scale but very few on the multiplicative scale. Thus, the responses to multiple stressors were well predicted from single stressor effects when combined as multiplicative effects.
Conclusion
I discuss how the lack of strong interactions could be due to model assumptions, the structure of the model, or oversimplified representation of stressor effects. Alternatively, the model and analysis may be sufficiently realistic and weak interactions on the multiplicative scale may be common. This would reduce a complicated multi-factor situation to a series of more tractable single-factor effects. A critical next step is to determine how we can a priori identify situations of low interactions (i.e., predictable from single-stressor effects) without having to already know the multi-stressor response.
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Continue reading ‘Sometimes (often?) responses to multiple stressors can be predicted from single-stressor effects: a case study using an agent-based population model of croaker in the Gulf of Mexico’A global biogeography analysis reveals vulnerability of surface marine zooplankton to anthropogenic stressors
Published 16 January 2024 Science ClosedTags: abundance, biological response, globalmodeling, modeling, otherprocess, performance, zooplankton
Highlights
- Multiple stress factors for zooplankton overlap in the surface ocean
- Stress brought by surface warming and acidification strongly increased in ∼50 years
- More research on anthropogenic impacts on zooplankton is urgently needed
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Summary
Anthropogenic impacts on zooplankton at the surface ocean pose an urgent challenge because these keystone species are crucial for oceanic processes. Some anthropogenic stressors for zooplankton have been identified, such as acidification due to climate change, but a multitude of other stressors exist, and the combination of these may lead to unknown impacts. We utilized global biogeochemical models to assess the temporal and spatial distribution of zooplankton stress factors, including changes in sea surface temperature, acidification, prey quantity, food quality, and contaminants. We highlighted regional hotspots where multiple stress factors overlap and revealed that most stress factors are increasing. By linking stress factors to zooplankton distribution, we introduced a zooplankton vulnerability index. We found that the zooplankton vulnerability index has doubled in 50 years, and this suggests that zooplankton populations are increasingly at risk from anthropogenic stressors. Further research is needed to develop strategies for mitigating the impacts of anthropogenic stressors on zooplankton.
Continue reading ‘A global biogeography analysis reveals vulnerability of surface marine zooplankton to anthropogenic stressors’Functional changes across marine habitats due to ocean acidification
Published 15 January 2024 Science ClosedTags: abundance, biological response, BRcommunity, calcification, chemistry, community composition, communitymodeling, field, growth, Mediterranean, modeling, otherprocess, performance, photosynthesis, reproduction, vents
Global environmental change drives diversity loss and shifts in community structure. A key challenge is to better understand the impacts on ecosystem function and to connect species and trait diversity of assemblages with ecosystem properties that are in turn linked to ecosystem functioning. Here we quantify shifts in species composition and trait diversity associated with ocean acidification (OA) by using field measurements at marine CO2 vent systems spanning four reef habitats across different depths in a temperate coastal ecosystem. We find that both species and trait diversity decreased, and that ecosystem properties (understood as the interplay between species, traits, and ecosystem function) shifted with acidification. Furthermore, shifts in trait categories such as autotrophs, filter feeders, herbivores, and habitat-forming species were habitat-specific, indicating that OA may produce divergent responses across habitats and depths. Combined, these findings reveal the importance of connecting species and trait diversity of marine benthic habitats with key ecosystem properties to anticipate the impacts of global environmental change. Our results also generate new insights on the predicted general and habitat-specific ecological consequences of OA.
Continue reading ‘Functional changes across marine habitats due to ocean acidification’
