Posts Tagged 'crustaceans'

Effects of ocean acidification on copepods

Highlights

• Ocean acidification (OA) has been a global threat to marine ecosystem.
• Copepods display species-specific and stage-dependent responses against OA.
• OA effects on copepods can be modulated by acclimatization/adaptation.
• The response of copepods against OA interacts with other co-stressors.
• Future priority researches have been suggested for OA stress study.

Abstract

Ocean acidification (OA) leads to significant changes in seawater carbon chemistry, broadly affects marine organisms, and considered as a global threat to the fitness of marine ecosystems. Due to the crucial role of copepods in marine food webs of transferring energy from primary producers to higher trophic levels, numerous studies have been conducted to examine the impacts of OA on biological traits of copepods such as growth and reproduction. Under OA stress, the copepods demonstrated species-specific and stage-dependent responses. Notably, different populations of the same copepod species demonstrated different sensitivities to the increased pCO2. In copepods, the deleterious effects of OA are also reinforced by other naturally occurring co-stressors (e.g., thermal stress, food deprivation, and metal pollution). Given that most OA stress studies have focused on the effects of short-term exposure (shorter than a single generation), experiments using adults might have underestimated the damaging effects of OA and the long-term multigenerational exposure to multiple stressors (e.g., increased pCO2 and food shortage) will be required. Particularly, omics-based technologies (e.g., genomics, proteomics, and metabolomics) will be helpful to better understand the underlying processes behind biological responses (e.g., survival, development, and offspring production) at the mechanistic level which will improve our predictions of the responses of copepods to climate change stressors including OA.

Continue reading ‘Effects of ocean acidification on copepods’

The immune-related fatty acids are responsive to CO2 driven seawater acidification in a crustacean brine shrimp Artemia sinica

Highlights

• The composition of fatty acids was clearly altered by seawater acidification in brine shrimp.
• The immune-related fatty acids were responsive to seawater acidification in brine shrimp.
• Physiology like the metabolism of fatty acids in crustacean was indeed affected by CO2 driven seawater acidification.

Abstract

The gradual increase of CO2 concentration in the atmosphere, absorbed by the ocean surface water through air to sea equilibration termed ocean acidification (OA), leads to the decline of pH in seawater. It is not clear so far how the composition of fatty acids, particular the immune-related, in marine crustacean and the subsequent energy supply in marine ecosystem are affected by OA. The brine shrimp Artemia sinica is an open and common feed that provide essential fatty acids for mariculture. In this study, the fatty acids profiles of brine shrimp cultured under different lower pH levels of CO2 driven seawater were investigated. The results showed a significant reduction of the proportion of total saturated fatty acids under the pH7.6 within one week. Meanwhile, the percentage of total monounsaturated fatty acids was significantly decreased at day 14 under pH7.8, and this percentage gave a significant increase of proportion within one week under pH7.6. Furthermore, the relative content of total polyunsaturated fatty acids (PUFAs) was found to be clearly increased with exposure to different seawater acidification at day 1, suggesting that the brine shrimp immune response was likely to be affected by acidified seawater as the PUFAs have been well known to be involved in immunomodulatory effects through alterations on cell membrane fluidity/lipid mediators and gene expression of cell signaling pathways. Notably, eicosapentaenoic acid and docosahexaenoic acid, which have essential effect on various physiological processes such as inflammatory cytokines production and cell structural stability, were strongly increased under two lower pH treatments within one week and with the significant increase at day 1 under pH7.6. These data clearly supported the hypothesis that OA might affect fatty acids composition, likely also the innate immunity, in crustacean and the subsequent energy transfer by food-chain system in the marine ecosystem.

Continue reading ‘The immune-related fatty acids are responsive to CO2 driven seawater acidification in a crustacean brine shrimp Artemia sinica’

Alteration of host-pathogen interactions in the wake of climate change – Increasing risk for shellfish associated infections?

Highlights

• Stressors induced by climate changes are causing immunosuppressed invertebrates with impaired bacteriostatic capacity.
• Climate changes increase distribution and abundance of human pathogens in coastal waters.
• Resulting in: Increased risk for pathogen transmission to shellfish consumers Need for more reliable pathogen indicators.

Abstract

The potential for climate-related spread of infectious diseases through marine systems has been highlighted in several reports. With this review we want to draw attention to less recognized mechanisms behind vector-borne transmission pathways to humans. We have focused on how the immune systems of edible marine shellfish, the blue mussels and Norway lobsters, are affected by climate related environmental stressors. Future ocean acidification (OA) and warming due to climate change constitute a gradually increasing persistent stress with negative trade-off for many organisms. In addition, the stress of recurrent hypoxia, inducing high levels of bioavailable manganese (Mn) is likely to increase in line with climate change. We summarized that OA, hypoxia and elevated levels of Mn did have an overall negative effect on immunity, in some cases also with synergistic effects. On the other hand, moderate increase in temperature seems to have a stimulating effect on antimicrobial activity and may in a future warming scenario counteract the negative effects. However, rising sea surface temperature and climate events causing high land run-off promote the abundance of naturally occurring pathogenic Vibrio and will in addition, bring enteric pathogens which are circulating in society into coastal waters. Moreover, the observed impairments of the immune defense enhance the persistence and occurrence of pathogens in shellfish. This may increase the risk for direct transmission of pathogens to consumers. It is thus essential that in the wake of climate change, sanitary control of coastal waters and seafood must recognize and adapt to the expected alteration of host-pathogen interactions.

Continue reading ‘Alteration of host-pathogen interactions in the wake of climate change – Increasing risk for shellfish associated infections?’

Socioeconomic risk from ocean acidification and climate change impacts on Atlantic Canadian fisheries

Ocean acidification (OA) is an emerging consequence of anthropogenic carbon dioxide emissions. The full extent of the biological impacts are currently not well understood. However, it is expected that invertebrate species that rely on the mineral calcium carbonate will be among the first and most severely affected. Despite the limited understanding of impacts there is a need to identify potential pathways for human societies to be affected by OA. Research on these social implications is a small but developing field of literature. This thesis contributes to this field by using a risk assessment framework, informed by a biophysical model of future species distributions, to investigate Atlantic Canadian risk from changes in shellfish fisheries. New Brunswick and Nova Scotia are expected to see declines in resource accessibility. While Newfoundland and Labrador and PEI are more socially vulnerable to losses in fisheries, they are expected to experience relatively minor changes in access.

Continue reading ‘Socioeconomic risk from ocean acidification and climate change impacts on Atlantic Canadian fisheries’

Ocean acidification ameliorates harmful effects of warming in primary consumer

Climate change-induced warming and ocean acidification are considered two imminent threats to marine biodiversity and current ecosystem structures. Here, we have for the first time examined an animal’s response to a complete life cycle of exposure to co-occurring warming (+3°C) and ocean acidification (+1,600 μatm CO2), using the key subarctic planktonic copepod, Calanus finmarchicus, as a model species. The animals were generally negatively affected by warming, which significantly reduced the females’ energy status and reproductive parameters (respectively, 95% and 69%–87% vs. control). Unexpectedly, simultaneous acidification partially offset the negative effect of warming in an antagonistic manner, significantly improving reproductive parameters and hatching success (233%–340% improvement vs. single warming exposure). The results provide proof of concept that ocean acidification may partially offset negative effects caused by warming in some species. Possible explanations and ecological implications for the observed antagonistic effect are discussed.

Continue reading ‘Ocean acidification ameliorates harmful effects of warming in primary consumer’

Counteractive effects of increased temperature and pCO2 on the thickness and chemistry of the carapace of juvenile blue crab, Callinectes sapidus, from the Patuxent River, Chesapeake Bay

Highlights

• Effect of climate change on crab carapace thickness and chemistry was examined
• Carapace thickness and high-Mg calcite content decreased at higher temperature
• Carapace Mg and high-Mg calcite content increased at higher pCO2
• Climate change may cause tradeoffs between growth and carapace thickness or chemistry

Abstract

Exoskeletons are central to the physiology and survival of marine invertebrates, but future increases in the temperature and pCO2 of the marine environment may alter the biomineralization processes involved in their formation. Thus, it is important to consider the impacts of a changing climate on the functionality of invertebrate exoskeletons. In this study, juvenile blue crab, Callinectes sapidus, from the Chesapeake Bay were exposed to increased temperature and pCO2 in a 2 × 2 factorial design for a period of two molts (approximately 30 days). Treatment levels were chosen to represent current (26 °C and 800 μatm CO2) and predicted future conditions in the year 2100 (32 °C and 8000 μatm CO2) in the Chesapeake Bay. Thickness was determined by light microscopy and carapace calcium (Ca) and magnesium (Mg) content were determined by Inductively Coupled Plasma – Atomic Emission Spectrometry. All Ca and Mg in the carapace were assumed to be present in the form of high‑magnesium calcite (HMC). Increased temperature decreased the thickness of juvenile blue crab carapaces by 8.5% and significantly reduced weight percent HMC by 2.0% (P < 0.05). Increased pCO2 significantly increased weight percent HMC by 2.0% but a significant increase in Mg content was also found. The observed counteractive effects of temperature and pCO2 on weight percent HMC underscore the importance of assessing such interactions in studies that quantify the impacts of multiple environmental stressors. Combined with new data regarding the influence of increased temperature and pCO2 on blue crab growth, the results of this study indicate tradeoffs between carapace thickness and chemistry with growth in juvenile blue crab exposed to future warming.

Continue reading ‘Counteractive effects of increased temperature and pCO2 on the thickness and chemistry of the carapace of juvenile blue crab, Callinectes sapidus, from the Patuxent River, Chesapeake Bay’

Interactive effects of increased temperature, pCO2 and the synthetic progestin levonorgestrel on the fitness and breeding of the amphipod Gammarus locusta

Highlights

  • Combined effects of temperature, pCO2 and levonorgestrel on G. locusta were assessed.
  • G. locusta was strongly negatively affected under warming exposure (+4 °C).
  • Growth rates were significantly affected by the interactions of LNG with temperature and pCO2.
  • A negative effect of higher temperature and acidification on G. locusta fecundity was observed, contrarily to LNG.
  • Increased temperature and pCO2 were clearly more adverse for G. locusta than exposure to LNG.

Abstract

Given the lack of knowledge regarding climate change-chemical exposure interactions, it is vital to evaluate how these two drivers jointly impact aquatic species. Thus, for the first time, we aimed at investigating the combined effects of increased temperature, pCO2 and the synthetic progestin levonorgestrel on survival, growth, consumption rate and reproduction of the amphipod Gammarus locusta. For that, a full factorial design manipulating temperature [ambient temperature and warming (+4 °C)], pCO2 [normocapnia and hypercapnia (Δ pH 0.5 units)] and the progestin levonorgestrel (LNG: L1 – 10 ngLL−1 and L2 – 1000 ngLL−1, control – no progestin and solvent control – vehicle ethanol (0.01%)) was implemented for 21 days. G. locusta was strongly negatively affected by warming, experiencing higher mortality rates (50–80%) than in any other treatments. Instead, growth rates were significantly affected by interactions of LNG with temperature and pCO2. It was observed, in the short-term (7d) that under ambient temperature (18 °C) and hypercapnic conditions (pH 7.6), the LNG presence promoted the amphipod’s growth, while in the medium-term (21d) this response was not observed. Relative consumption rates (RCRs), during the first week were higher than in the third week. Furthermore, in the first week, RCRs were negatively affected by higher temperature while in the third week, RCRs were negatively affected by acidification. Furthermore, it was observed a negative effect of higher temperature and acidification on G. locusta fecundity, contrarily to LNG. Concluding, the impact of increased temperature and pCO2 was clearly more adverse for the species than exposure to the synthetic progestin, however, some interactions between the progestin and the climate factors were observed. Thus, in a future scenario of global change, the presence of LNG (and other progestins alike) may modulate to a certain level the effects of climate drivers (and vice-versa) on the gammarids fitness and reproduction.

Continue reading ‘Interactive effects of increased temperature, pCO2 and the synthetic progestin levonorgestrel on the fitness and breeding of the amphipod Gammarus locusta’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book