Physiological and ecological responses of crustaceans to ocean acidification

Abstract

The sensitivity of marine crustaceans to ocean acidification is poorly understood, but can be assessed by combining data from physiological and ecological studies. The species most at risk are exclusively marine and have limited physiological capacities to adjust to environmental change. They are poor iono-and osmoregulators and have limited abilities to compensate for acid -base disturbances. The problems are compounded in slow-moving, relatively inactive species because they have low circulating protein levels and low buffering capacities. Species living in low-energy environments, such as deep-sea and polar habitats, are particularly vulnerable, because they are metabolically limited with respect to environmental change. Elevated pCO 2 levels in seawater, such as those predicted for the year 2300, are known to have diverse effects on calcification rate, little effect on egg production and a negative effect on growth rate and moulting frequency in marine crustacean species. At these levels, embryonic development is negatively impacted, but larval and juvenile stages do not appear to be affected, unless the changes in pCO 2 are accompanied by rising temperatures. Overall, marine crustaceans are broadly tolerant to the seawater pCO 2 levels expected by 2100 and 2300, but only in the medium-term (weeks) and only in the more adaptable species. The reductions in growth rate are of concern, as these changes could affect species survival, distribution and abundance. Studies are urgently needed to evaluate whether the patterns of vulnerability identified here in crustaceans will still be relevant after long-term (months) exposure to the relevant pCO 2 levels, in combination with changes in other environmental factors.

Deformities in larvae and juvenile European lobster (<i>Homarus gammarus</i>) exposed to lower pH at two different temperatures

“…Whiteley (2011) not affect larval conditions. However, Arnold et al (2009) analysed the calcium and magnesium concentrations per surface area of the carapace of H. gammarus larvae.…”

Finding the way to the top: how the composition of oceanic mid-trophic micronekton groups determines apex predator biomass in the central North Pacific

“…ocean acidification, expanding oxygen minimum zones, ocean warming, in creased stratification) may disproportionately affect certain types of micronekton, thereby shunting or rerouting previously available flows of biological production available to apex species. For example, calcifying organisms such as pelagic crustaceans or the early life stages of cephalo pods and other mollusks may be particularly sensitive to changes in oceanic carbonate chemistry (Fabry et al 2008, Whiteley 2011, Kaplan et al 2013a. Thus, focused studies examining the specific food web relationships of mid-trophic micronekton to economically valued apex species are needed amidst a changing marine environment.…”

Sensitivity to ocean acidification parallels natural pCO 2 gradients experienced by Arctic copepods under winter sea ice

“…Hence, predicting how organisms and ecosystems respond to OA is currently restricted to studies from subarctic and/or icefree Arctic systems because of the technical difficulties and costs involved in sampling remote ice-associated Arctic locations. Given that the Arctic is recognized as a "bellwether" for global OA processes (2) and that polar species are potentially more sensitive to these changes due to their reduced metabolic scope (6), this lack of data on Arctic under-ice zooplankton responses to changes in current and future carbonate chemistry represents a serious knowledge gap and limits predictive modeling capabilities of future scenarios.…”