Ocean acidification represents a significant and growing threat to some species of marine plankton, with wide-ranging implications for marine ecosystems and the services they provide. The alterations in plankton physiology, behavior, and community structure under acidified conditions exemplify the profound impact of anthropogenic CO₂ emissions on the ocean’s smallest, yet most essential inhabitants.
Continue reading ‘Ocean acidification and plankton’Posts Tagged 'performance'
Ocean acidification and plankton
Published 10 December 2024 Science ClosedTags: biological response, community composition, otherprocess, performance, physiology, phytoplankton, review
Physiological and behavioral responses of the Baltic clam Macoma balthica to a laboratory simulated CO2-leakage from a subseabed carbon storage site
Published 3 December 2024 Science ClosedTags: biological response, laboratory, mollusks, morphology, mortality, North Atlantic, performance, physiology
Highlights
- Baltic clams were exposed to CO2 leakage simulated in laboratory conditions.
- Physiological and behavioral responses of the model organism were evaluated.
- Shell growth in thickness and length were inhibited at pH 6.3.
- Biochemical composition, condition index and burrowing depth results were inconclusive.
Abstract
Carbon capture and storage in sub-seabed geological reservoirs is now officially included in the atmospheric CO2 emissions reduction policy and meets the agenda of Sustainable Development Goals (SDGs). Over the last few years biological risk assessment studies have delivered substantial empirical data on possible consequences of CO2 leakages from underwater storage sites on benthic systems. Current knowledge on Carbon Capture and Storage CCS associated risks is limited to marine systems. Yet there are multiple areas identified as suitable for carbon storage, but their hydrogeochemical features are so distinct that they should be studied as separate cases. Baltic Sea is one example of an area but is host to a unique – in a world scale – ecosystem with low salinity in combination with reduced oxygen availability in the benthic zone. Geological surveys have designated a potential storage site in the Southern Baltic Sea, namely the B3 oil field. Thus, this study focuses on biological effects of seawater acidification caused by a simulated CO2 leakage scenarios under laboratory conditions on a model macrobenthic in-faunal species. Baltic clams Macoma balthica were exposed to different environmental pH scenarios: pH 7.7 (no leakage), pH 7.0 (moderate hypercapnia) and pH 6.3 (severe hypercapnia) in three independent experiments conducted with the use of a hyperbaric tank (Karl Eric Titank) mimicking hydrostatic pressure of 900 kPa, relevant to conditions at the B3 field. Selected physiological aspects of the Baltic clam, such as survival, shell growth rate, morphometric condition and biochemical composition were investigated along with their behavioral responses, i.e. sediment burrowing activity. The results showed modest effects of hypercapnia on physiological performance of the clams that did not lead to greater mortality in neither of the tested leakage scenarios. Apart from high survival of the clams even in the lowest seawater pH (6.3) there were only little changes observed in the burrowing depth of the clams and biochemical composition of their soft tissues related to seawater acidification. The most evident physiological responses of the clams to prolonged hypercapnia (40 days at pH 6.3) were manifested in decreased shell growth.
The effects of ocean acidification on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis
Published 27 November 2024 Science ClosedTags: biological response, crustaceans, laboratory, molecular biology, North Pacific, performance, physiology
Increases in atmospheric carbon dioxide (CO2) lead to ocean acidification (OA) which has been shown to alter olfactory behaviours in marine organisms. However, coastal regions experience CO2 levels greater than end-of-century open ocean predictions. I investigated the effects of OA on the olfactory system of the intertidal yellow shore crab, Hemigrapsus oregonensis. I hypothesized that given their variable natural environment these crabs are more tolerant to OA. Crabs demonstrated impaired olfactory behaviour after acute and long-term static exposures to OA. This impairment was correlated with a decrease in olfactory receptor protein expression and a 20% decrease in olfactory sensory neuron volume. Crabs exposed to fluctuating CO2 had intermediate behavioural responses and showed no changes in receptor expression. These results show that coastal crabs are affected by ocean acidification despite their variable natural environment, being particularly vulnerable during upwelling events and this impairment will likely worsen in the future.
Continue reading ‘The effects of ocean acidification on the olfactory system of the yellow shore crab, Hemigrapsus oregonensis’Cross-talk between tissues is critical for intergenerational acclimation to environmental change in Acanthochromis polyacanthus
Published 21 November 2024 Science ClosedTags: adaptation, biological response, fish, laboratory, molecular biology, otherprocess, performance, physiology, reproduction
Organisms’ responses to environmental changes involve complex, coordinated responses of multiple tissues and potential parental influences. Here using a multi-tissue approach we determine how variation in parental behavioural tolerance and exposure to elevated CO2 influences the developmental and intergenerational molecular responses of their offspring in the coral reef fish Acanthochromis polyacanthus to future ocean acidification (OA) conditions. Gills and liver showed the highest transcriptional response to OA in juvenile fish regardless of parental OA conditioning, while the brain and liver showed the greatest intergenerational acclimation signals. Developmentally induced signals of OA, such as altered neural function in the brain, were restored to control levels after intergenerational exposure. Intergenerational CO2 exposure also enabled the offspring to adjust their metabolic processes, potentially allowing them to better meet the energetic demands of a high CO2 environment. Furthermore, offspring of OA-exposed parents differentially expressed a new complement of genes, which may facilitate intergenerational acclimatory responses. A genetic component of intergenerational plasticity also played a crucial role, with the parental behavioural phenotype largely determining the offspring’s transcriptional signals. Overall, our results reveal tissue-specific transcriptional changes underlying intergenerational plastic responses to elevated CO2 exposure, enhancing understanding of organismal acclimation to OA throughout the whole body.
Continue reading ‘Cross-talk between tissues is critical for intergenerational acclimation to environmental change in Acanthochromis polyacanthus’Combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in Chinese mitten crab Eriocheir sinensis
Published 6 November 2024 Science ClosedTags: biological response, BRcommunity, crustaceans, laboratory, performance, physiology, prokaryotes
Highlights
- Low pH stress might disturb the maintaining of protein homeostasis in hemocytes.
- Combination of low pH stress and bacterial infection cause disruption of TLR pathway.
- Low pH stress and bacterial infection inhibit the TCA cycle in hemocytes.
Abstract
Water pH is a critical environmental factor for aquaculture. Acidification is a pressing environmental issue that poses significant threats to the aquaculture industry. Since the outbreaks of disease generally accompany with environmental stress, comparative transcriptome analyses were performed to investigate the combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in the economically important crab Eriocheir sinensis. The results revealed that the immune deficiency (IMD) pathway and prophenoloxidase (proPO) system was activated to defense against Vibro parahaemolyticus even when crabs were subjected to low pH stress, whereas low pH stress resulted in the disorder of Toll-like receptor (TLR) pathway upon V. parahaemolyticus infection. Moreover, low pH stress might weaken crabs′ defense against V. parahaemolyticus by inhibiting the up-regulation of crustin and suppressing the expression of lysozyme, and disturb the maintaining of protein homeostasis through the transcriptional decrement of a batch of heat shock proteins (HSPs). It is worth noting that both V. parahaemolyticus infection and low pH stress might suppress the energy metabolism in the hemocytes via inhibiting the expression of critical enzymes, dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex and fumarase, in the tricarboxylic acid (TCA) cycle. This study provides novel understandings concerning the transcriptional changes of hemocyte in E. sinensis subjected to a combination of low pH stress and V. parahaemolyticus infection as well as contribute to optimize the management strategies for the prevention and control of diseases in E. sinensis farming.
Continue reading ‘Combined effects of low pH stress and bacterial infection on the transcriptional changes of hemocytes in Chinese mitten crab Eriocheir sinensis’Improved growth performance and physiological state in hybrid abalone (Haliotis rufescens and Haliotis fulgens) facing ocean acidification conditions
Published 1 November 2024 Science ClosedTags: biological response, BRcommunity, mollusks, morphology, mortality, performance, physiology, respiration
Highlights
- Hybrid vigor in abalones evaluated under future ocean acidification scenarios.
- Hybrid cross abalone show positive heterosis on biological performance.
- More robust metabolic response observed in hybrids than in pure abalone crosses.
- Higher heterosis for survival and shell growth reached at pH 7.8 conditions.
- Interspecific hybridization yield resilient cross withstand ocean acidification.
Abstract
Abalone (Haliotis spp.) is a valuable global aquaculture resource in Mexican abalone industry, particularly red (Haliotis rufescens) and green (H. fulgens) abalone, showing significant growth. However, climate change -particularly ocean acidification (OA)- threatens production by negatively impacting mollusks, leading to recruitment failures, poor fertilization, malformations, and reduced calcification and growth jeopardizing sustainability and food security. This study aims to assess robustness of a hybrid abalone cross RF (H. rufescens ♀ x H. fulgens ♂) to OA conditions by evaluating biological performance (survival, growth in weight and length) and metabolic response (oxygen consumption, ammonia excretion rate, and atomic O:N ratio). Juveniles from hybrid RF cross and two pure parental crosses (RR, FF) were exposed to three pH levels: control (pH ≈ 8.0) and two reduced pH scenarios (pH 7.8 and 7.5), representing moderate and severe OA conditions. The results showed hybrid cross exhibiting better growth and metabolic response than pure crosses under all conditions. Notably, hybrid length growth was superior under moderate OA conditions (pH 7.8) compared to control (pH 8.0) and intense OA conditions (pH 7.5). Enhanced physiological hybrid status was evidenced by increased oxygen consumption and stable ammonia excretion, reflected in higher atomic O:N ratio. This study demonstrates hybrid cross RF robustness under OA conditions and supports interspecific hybridization as potential mitigation strategy to alleviate negative OA effects for sustainable abalone production.
Continue reading ‘Improved growth performance and physiological state in hybrid abalone (Haliotis rufescens and Haliotis fulgens) facing ocean acidification conditions’Chapter 6 – Impacts of ocean acidification on the behavior of marine mollusks
Published 22 October 2024 Science ClosedTags: biological response, BRcommunity, laboratory, mollusks, performance
Ocean acidification, a direct consequence of increasing carbon dioxide (CO2) emissions, is a pressing environmental issue that has far-reaching implications for marine ecosystems (Doney et al., 2009). The oceans absorb approximately one-third of the CO2 produced by human activities, leading to decreased seawater pH, a process known as ocean acidification (Rodriguez, 2012). This phenomenon has been identified as a significant threat to marine life, mainly invertebrates such as mollusks, echinoderms, and crustaceans, which rely on carbonate ions to build their shells and skeletons (Guinotte and Fabry, 2008; Doney et al., 2020).
Continue reading ‘Chapter 6 – Impacts of ocean acidification on the behavior of marine mollusks’Ecophysiology and ocean acidification in marine mollusks: from molecule to behavior
Published 17 October 2024 Science ClosedTags: biological response, education, growth, mollusks, morphology, performance, physiology, reproduction, review, socio-economy
Ecophysiology and Ocean Acidification in Marine Mollusks: From Molecule to Behavior provides an extensive overview of the latest research on the various ecophysiological effects of ocean acidification on marine mollusks. This book synthesizes historical information and recent findings on the effects of environmental change, ocean warming, and acidification on key mollusks and their life-history. It also discusses the underlying mechanisms underpinning the effects of ocean warming and acidification. Written by internationally recognized experts in the field of marine biology, this book systematically examines the effects of ocean acidification on the reproduction, growth and development, physiological metabolism, immunity, and behavior of marine mollusks.
The book concludes by discussing the implications of current research, acknowledging data limitations in the field, and proposing future research directions, providing a better understanding of the potential impacts of ocean acidification on mollusks and the global aquaculture industry and inspiring new thinking for future research practices. It will be an indispensable resource for researchers, practitioners, undergraduate and graduate students, conservationists, and aquaculturists alike who are interested in marine environmental change, ecology, physiology, and marine biology.
Continue reading ‘Ecophysiology and ocean acidification in marine mollusks: from molecule to behavior’Mutligenerational chronic exposure to near future ocean acidification in European sea bass (Dicentrarchus labrax): insights into the regulation of the transcriptome in a sensory organ involved in feed intake, the tongue
Published 10 October 2024 Science ClosedTags: biological response, BRcommunity, fish, laboratory, molecular biology, performance, physiology
Highlights
- Multigenerational exposure to OA has no impact on teeth mineralization in Sea bass.
- Of the 18703 genes expressed in the tongue, 295 exhibited OA-induced regulation.
- Genes related to cell stress, immune system and fatty acid sensitivity are regulated.
- OA impacts the branchial expression of p2ry4 gene involved in gustatory system.
Abstract
In this study, we examined the effect of near future ocean acidification (OA) on the transcriptome of a sensory organ in contact with surrounding water, the tongue in adult European sea bass (Dicentrarchus labrax) by mean of RNAseq experiment. We acquired a total of 14.1 Mb quality-trimmed reads covering 18,703 expressed genes from the tongue of fish reared from two generations at actual (pH 8.0 condition) and predicted near-future seawater pH (pH 7.6 condition). Gene ontologies analyses of expressed genes support the evidence that the tongue exhibits biological processes related to the sensory system, tooth mineralization and immune defences among others. Our data revealed only 295 OA-induced regulated genes with 114 up- and 181 down-regulated by OA. Functions over-represented encompass processes involved in organic substance metabolic process, RNA metabolism and especially RNA methylation which, combined with the regulation of some hsp genes expression, suggest a molecular response to stress which might contribute to lingual cell homeostasis under OA. The immune system process is also found enriched within OA-induced regulated genes. With the exception of one fatty acid receptor, known taste perception effectors were not impacted by OA in the tongue. However, a complementary droplet digital PCR approach dedicated to genes involved in gustatory signal transduction revealed the down regulation by OA of pyrimidinergic receptor (p2ry4) transcript expression in the gills of the fish. Combined with scanning electron microscopy analysis, our RNAseq data revealed that OA has no impact on processes related to teeth development and mineralization. Altogether, our data reveal that multigenerational exposure to OA has not a substantially effect on the tongue transcriptome but emphasis should be placed on investigating the potential physiological consequences related to the regulation of genes related to cell stress, immune system and fatty acid sensitivity to conclude on species resilience in face of OA.
Continue reading ‘Mutligenerational chronic exposure to near future ocean acidification in European sea bass (Dicentrarchus labrax): insights into the regulation of the transcriptome in a sensory organ involved in feed intake, the tongue’Impact of low pH/high pCO2 on the physiological response and exopolysaccharide content in cyanobacteria Trichodesmium erythraeum
Published 26 September 2024 Science ClosedTags: biological response, BRcommunity, growth, laboratory, morphology, performance, prokaryotes
The acidification of the ocean caused by the diffusion of anthropogenic carbon dioxide (CO2) into seawater has been believed to threaten the stability of the marine ecosystem. As one of the major contributors to the primary production in oligotrophic oceans, the response of Trichodesmium to the acidification of the ocean has attracted a lot of attention. Therefore, in this study, we applied physiological and biochemical methods to identify the influences of high pCO2 and low pH conditions on the growth of T. erythraeum. Our results showed that the low pH during the acidification of the ocean was the main factor inhibiting the growth of T. erythraeum. In addition, low pH caused oxidative stress to T. erythraeum, as evidenced by the increase of the reactive oxygen species and antioxidant enzyme’s activities. The activity of carbonic anhydrase (CA) enzyme is dually regulated by pCO2 and pH, and T. erythraeum can adapt to different levels of pCO2 and pH in seawater by flexibly adjusting CA enzyme activity. We also discovered that the stimulatory effect of high pCO2 on the exopolysaccharide (EPS) content of T. erythraeum outweighed the inhibitory effect of low pH during the process of ocean acidification. In conclusion, this study systematically revealed the effects of high pCO2 and low pH caused by the acidification of the ocean on the growth and EPS of T. erythraeum. These results provide new insights into the response mechanisms of T. erythraeum in the acidified ocean under future climate conditions.
Continue reading ‘Impact of low pH/high pCO2 on the physiological response and exopolysaccharide content in cyanobacteria Trichodesmium erythraeum’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
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’Interactive impact of residual pyrethroid compounds used in the Chilean salmon farming industry and coastal acidification conditions on the feeding performance of farmed mussels in northern Patagonia
Published 3 September 2024 Science ClosedTags: biological response, fisheries, laboratory, mollusks, multiple factors, performance, physiology, reproduction, socio-economy, temperature
Highlights
- We examine the interaction of natural environmental regimes of temperature and pH conditions, with pyrethroids concentration used by salmon farming industry in Chilean Patagonia, and its potential impact of mussel feeding (clearance and ingestion rate of newly-hatched larvae and juveniles).
- We combined approaches, including oceanographic monitoring in a salmon and mussel farming area in Chilean Patagonia, with experiments aiming estimate the effects of two pyrethroids (deltamethrin and cypermethrin) on the clearance and ingestion rate of mussel larvae.
- We also exposed to mussel spats to both pyrethroids, but at contrasting temperature and pH conditions mimicking winter and summer conditions.
Abstract
The use of pyrethroids in aquaculture has been an important component of achieving a thriving salmon farming industry in Chile. While the residual presence of such substances is known to depend on environmental conditions, most ecotoxicological studies to date have not considered environmental context. Here, we conducted oceanographic monitoring combined with experiments aiming to estimate the effects of two pyrethroids on the feeding rates of larvae of farmed mussels, Mytilus chilensis. In additional experiments, mussel spats were exposed to both pyrethroids, but under contrasting temperature/pH so as to mimic winter and summer conditions. Experiments mimicking spring conditions revealed that both pyrethroid substances affected the feeding of mussel larvae as a function of concentration. Conversely, significant impact of pyrethroids on adults were not observed with regard to temperature and pH, but a significant impact of low temperature/low pH condition on ingestion rates was confirmed. Given the current status of increasing ocean acidification, the results of this study are expected to provide useful information with regard to achieving sustainable mussel aquaculture, especially considering both activities occur in similar geographic areas, and the expansion of salmon farming areas is ongoing in Chile.
Continue reading ‘Interactive impact of residual pyrethroid compounds used in the Chilean salmon farming industry and coastal acidification conditions on the feeding performance of farmed mussels in northern Patagonia’Effects of pH/pCO2 fluctuation on photosynthesis and fatty acid composition of two marine diatoms, with reference to consequence of coastal acidification
Published 30 August 2024 Science ClosedTags: biological response, chemistry, growth, laboratory, North Pacific, performance, photosynthesis, physiology, phytoplankton
Coastal waters are impacted by a range of natural and anthropogenic factors, which superimpose on effects of increasing atmospheric CO2, resulting in dynamically changing seawater carbonate chemistry. Research on influences of dynamic pH/pCO2 on marine ecosystem is still in its infancy, although effects of ocean acidification have been extensively studied. In the present study, we manipulated the culturing pH/pCO2 to investigate physiological performance and fatty acid (FA) composition of two coastal diatoms Skeletonema costatum and Thalassiosira weissflogii in both steady and fluctuating pH/pCO2 regimes. Generally, seawater acidification and pH variability showed neutral or positive effects on specific growth rate, chlorophyll a, and biogenic silica contents of two species. Elevated pCO2 inhibited net photosynthetic rate by 27 % and enhanced mitochondrial respiration rate of S. costatum by 36 % in the steady pH regime, while these rates were unaltered by elevated pCO2 in the fluctuating regime. Elevated pCO2 leaded to 21 % lower saturated FA and twofold increase in polyunsaturated FA proportions of T. weissflogii. Our results indicate that costal acidification could affect primary production in a different way from ocean acidification. Together with the altered nutritional quality of prey for higher trophic levels, coastal acidification might have far-reaching consequence for marine ecosystem functioning.
Continue reading ‘Effects of pH/pCO2 fluctuation on photosynthesis and fatty acid composition of two marine diatoms, with reference to consequence of coastal acidification’Integrated multi-biomarker responses of juvenile zebra seabream (Diplodus cervinus) to warming and acidification conditions
Published 29 August 2024 Science ClosedTags: biological response, chemistry, fish, growth, laboratory, mortality, multiple factors, North Atlantic, performance, physiology, reproduction, temperature
The impacts of climate change-related stressors are becoming more noticeable in the ocean, particularly in coastal marine ecosystems. Yet limited information still exists on the physiological state and ecological resilience of marine fish species, especially during their early life stages (i.e., larvae and juveniles). The present study investigated the effects of chronic exposure to seawater warming (OW; ΔT = +4 °C) and acidification (OA; ΔpH = −0.3 pH units, equivalent to pCO2~1000 µatm), acting alone or combined (OWA), on juvenile zebra seabream (Diplodus cervinus) physiological resilience, considering distinct levels of biological organization (i.e., biochemical, cell, organ and individual levels). After 60 days of exposure, both stressors, in isolation or combination, significantly decreased specific growth rate (−11% in OW, −42% in OA and −49% in OWA) and leukocyte counts (from −29% in OA and OWA up to −37% in OW) in relation to the control treatment. In addition, a decreased Fulton’s condition index (K) was observed under warming and acidification in combination (−35% in OWA). At the cell level, OW, OA and OWA triggered different biomarker responses in D. cervinus (i.e., up-regulation, down-regulation, or absence of significant effect). In general, the results are suggestive of an antagonistic effect when warming and acidification are combined. OWA yielded the highest integrated biomarker response (IBR) index value in the whole organism, muscle, brain and gills of D. cervinus juveniles, therefore suggesting that the effects of these stressors are more severe when they act together. The distinct patterns observed in each stress scenario highlight the importance of carrying out further studies adjusted to the specificities of different regions, i.e., accounting not only for the type and degree of severity of environmental stressors already felt and/or projected for that specific area, but also the physiological plasticity of species that inhabit a particular ecosystem. The gathered knowledge will allow one to determine the vulnerability of particular marine species and geographic areas and, most importantly, to draw up effective and tailor-made conservation strategies to overcome climate change impacts.
Continue reading ‘Integrated multi-biomarker responses of juvenile zebra seabream (Diplodus cervinus) to warming and acidification conditions’Can niche plasticity mediate species persistence under ocean acidification?
Published 27 August 2024 Science ClosedTags: algae, biological response, BRcommunity, chemistry, field, fish, performance, vents
Global change stressors can modify ecological niches of species, thereby altering ecological interactions within communities and food webs. Yet, some species might take advantage of a fast-changing environment, allowing species with high niche plasticity to thrive under climate change.
We used natural CO2 vents to test the effects of ocean acidification on niche modifications of a temperate rocky reef fish assemblage. We quantified three ecological niche traits (overlap, shift and breadth) across three key niche dimensions (trophic, habitat and behavioural).
Only one species increased its niche width along multiple niche dimensions (trophic and behavioural), shifted its niche in the remaining (habitat) was the only species to experience a highly increased density (i.e. doubling) at vents. The other three species that showed slightly increased or declining densities at vents only displayed a niche width increase in one (habitat niche) out of seven niche metrics considered. This niche modification was likely in response to habitat simplification (transition to a system dominated by turf algae) under ocean acidification.
We further showed that, at the vents, the less abundant fishes had a negligible competitive impact on the most abundant and common species. This species appeared to expand its niche space, overlapping with other species, which likely led to lower abundances of the latter under elevated CO2.
We conclude that niche plasticity across multiple dimensions could be a potential adaptation in fishes to benefit from a changing environment in a high-CO2 world.
Continue reading ‘Can niche plasticity mediate species persistence under ocean acidification?’Impact of fluctuating temperature and elevated CO2 on the growth, survival, and oxygen consumption of juvenile pinto abalone Haliotis kamtschatkana kamtschatkana Jonas
Published 22 August 2024 Science ClosedTags: biological response, chemistry, growth, laboratory, mollusks, mortality, North Pacific, performance, physiology, respiration
Pinto abalone populations in the Salish Sea, WA have declined precipitously in the last several decades and have not recovered despite fishery closure in 1994. The Puget Sound Restoration Fund, in collaboration with state and federal agencies, has been outplanting juvenile pinto abalone at sites in the San Juan Archipelago, and some sites are much more successful than others despite similar physical characteristics. The sites, however, likely differ in oceanic parameters, such as temperature, salinity, and pH, which are in turn changing as the climate of the Earth is changing. The purpose of this study was to investigate the effects of temperature fluctuation and pCO2 levels on the survival, growth, and oxygen consumption of juvenile pinto abalone. In a fully crossed experiment, juvenile pinto abalone were held at either currently ambient (400 ppm) or elevated (1,200 ppm) pCO2 and at constant (10°C) or fluctuating (10 → 14 → 10°C) temperature. Survival was monitored weekly and growth was measured after 4 wk. In a second experiment, abalone were held in the same crossed pCO2 and temperature treatments, and oxygen consumption was measured. High pCO2 and fluctuating temperature both significantly decreased abalone survival. Abalone growth was not affected by pCO2 level (temperature could not be analyzed due to very poor survival in the fluctuating temperature treatments). In addition, there was an interaction between fluctuating temperature and pCO2 level on abalone oxygen consumption. Abalone in the constant temperature treatment had higher oxygen consumption when exposed to elevated pCO2; however, this pattern was not observed in the fluctuating temperature treatment. The results of this experiment indicate that outplant sites with minimal temperature fluctuation and lower pCO2 levels could lead to improvements in outplanting success of juvenile pinto abalone.
Continue reading ‘Impact of fluctuating temperature and elevated CO2 on the growth, survival, and oxygen consumption of juvenile pinto abalone Haliotis kamtschatkana kamtschatkana Jonas’Morphological and physiological responses of the cosmopolitan marine diatom Thalassiosira rotula to acidification
Published 13 August 2024 Science ClosedTags: biogeochemistry, biological response, chemistry, laboratory, morphology, North Atlantic, performance, physiology, phytoplankton
We investigated the effect of decreased pH on the morphology and nutrient physiology of the cosmopolitan marine diatom Thalassiosira rotula (CCMP3362) by acclimating unialgal cultures to two different CO2 gas concentrations under optimal light, temperature and nutrient conditions. At lower pH (higher CO2), T. rotula exhibited a reduction in cell diameter (7%), surface area (13%), and volume (20%), and an increase in surface area-to-volume ratio (7%). All measures of silicification in T. rotula, i.e., silica (SiO2) quota, rate of silicic acid (Si(OH)4) utilization, and elemental ratios of SiO2:C and SiO2:N, remained unchanged. Similarly, carbon (C) and nitrogen (N) quotas, ratios and utilization rates were mostly unaffected by pH. In contrast, the utilization rate of nitrate (ρNO3) was significantly lower at decreased pH when the rate was normalized by cell number instead of by cell volume. The changes in cell morphology found in this study under low pH were likely not large enough to significantly impact physiological processes and the role of this species in marine food webs and biogeochemical cycles. It is possible that the interactive effects of pH, temperature, light, and nutrient availability characteristic of different regions of the world ocean could result in stronger physiological and morphological responses in this widespread diatom. However, under constant optimal growth conditions, T. rotula was only mildly affected by changes in pH, and in particular the physiology and elemental stoichiometry of C, N and Si were not sensitive to acidification.
Continue reading ‘Morphological and physiological responses of the cosmopolitan marine diatom Thalassiosira rotula to acidification’The water content, apoptosis, and proliferation of the brain in marine medaka affected by seawater acidification
Published 8 August 2024 Science ClosedTags: biological response, chemistry, fish, laboratory, North Pacific, performance, physiology
A possible explanation for ocean acidification-induced changes in fish behavior is a systemic effect on the nervous system. Three biological barriers at the blood–brain interface effectively separate the brain from the body fluids. It is not known whether fish brain regions in contact with these barriers are affected by acidification. Here, we studied structural changes in medaka (Oryzias melastigma) brain regions contacting cerebrospinal fluid (CSF) after short-term (7 days) CO2 exposure. The brain water content decreased significantly and the superficial structure of the pia mater was changed, but there was no obvious damage to the internal structures of the brain after seawater acidification. Seawater acidification also led to an increase in apoptosis and a decrease in the number of proliferative cells in brain areas contacting CSF. These results indicate that the structure of CSF-contacting brain regions in medaka was affected by seawater acidification, and the brain responded to seawater acidification stress by increasing apoptosis and reducing proliferation.
Continue reading ‘The water content, apoptosis, and proliferation of the brain in marine medaka affected by seawater acidification’Unveiling the secrets of diatom-mediated calcification: implications for the biological pump
Published 19 July 2024 Science ClosedTags: abundance, biological response, chemistry, laboratory, North Pacific, otherprocess, performance, photosynthesis, phytoplankton
Siliceous diatoms are one of the most prominent actors in the oceans, and they account for approximately 40% of the primary production and particulate organic carbon export flux. It is believed that changes in carbon flux caused by variations in diatom distribution can lead to significant climate shifts. Although the fundamental pathways of diatom-driven carbon sequestration have long been established, there are no reports of CaCO3 precipitation induced by marine diatom species. This manuscript introduces novel details regarding the enhancement of aragonite precipitation during photosynthesis in Skeletonema costatum in both artificial and natural seawater. Through direct measurements of cell surfaces via a pH microelectrode and zeta potential analyzer, it was determined that the diatom-mediated promotion of CaCO3 precipitation is achieved through the creation of specific microenvironments with concentrated [CO32−] and [Ca2+] and/or the dehydrating effect of adsorbed Ca2+. Based on this mechanism, it is highly plausible that diatom-mediated calcification could occur in the oceans, an assertion that was supported by the significant deviation of total alkalinity (TA) from the conservative TA-salinity mixing line during a Skeletonema costatum bloom in the East China Sea and other similar occurrences. The newly discovered calcification pathway establishes a link between particulate inorganic and organic carbon flux and thus helps in the reassessment of marine carbon export fluxes and CO2 sequestration efficiency. This discovery may have important ramifications for assessing marine carbon cycling and predicting the potential effects of future ocean acidification.
Continue reading ‘Unveiling the secrets of diatom-mediated calcification: implications for the biological pump’Effects of elevated pCO2 on bioenergetics and disease susceptibility in Pacific herring Clupea pallasii
Published 17 July 2024 Science ClosedTags: biological response, chemistry, fish, growth, laboratory, mortality, North Pacific, performance, physiology, reproduction
Ocean acidification can affect the immune responses of fish, but effects on pathogen susceptibility remain uncertain. Pacific herring Clupea pallasii were reared from hatch under 3 CO2 partial pressure ( pCO2) treatments (ambient, ∼650 µatm; intermediate, ∼1500 µatm; high, ∼3000 µatm) through metamorphosis (98 d) to evaluate the effects of ocean acidification on bioenergetics and susceptibility to an endemic viral disease. Mortality from viral hemorrhagic septicemia (VHS) was comparable between herring reared under ambient and intermediate pCO2 (all vulnerability testing at ambient pCO2). By contrast, fish reared under high pCO2 experienced significantly higher rates of VHS mortality, and the condition factor of survivors was significantly lower than in the other pCO2 treatments. However, the prevalence of infection among survivors was not influenced by pCO2 treatment. Pre-flexion larval development was not affected by elevated pCO2, as growth rate, energy use, and feeding activity were comparable across treatments. Similarly, long-term growth (14 wk) was not affected by chronic exposure to elevated pCO2. Herring reared under both elevated pCO2 treatments showed an average reduction in swimming speed; however, wide intra-treatment variability rendered the effect nonsignificant. This study demonstrates that the VHS susceptibility and bioenergetics of larval and post-metamorphic Pacific herring are not affected by near-future ocean acidification predicted for coastal systems of the North Pacific. However, increased susceptibility to VHS in fish reared under 3000 µatm pCO2 indicates potential health and fitness consequences from extreme acidification.
Continue reading ‘Effects of elevated pCO2 on bioenergetics and disease susceptibility in Pacific herring Clupea pallasii’
