Impacts of OA and salinity on Crustacea

The purpose of this joint project with Bangor University was to examine the combined effects of two important climate change variables: carbon dioxide and salinity, on the survival and performance of two species of marine crabs with differing abilities to compensate for environmental change.
Although the interest in ocean acidification has intensified considerably over recent years, the effects of simultaneous exposure to reduced salinity has been comparatively overlooked by the scientific community. Very little is known about the simultaneous effects of reduced salinity, brought about by temperature-related increases in rainfall and ice melt, with increased sea water carbon dioxide concentration in a future 'high-CO2 world'.
Fluctuations in carbon dioxide and salinity are predicted to have their first effects in shallow shelf seas that typify the marine environment though much of Europe. It is clearly imperative that we understand the consequences of simultaneous changes in these key environmental drivers which may directly and indirectly impact on health, productivity and economic value of these important ecosystems
Our work emphasised the dominant impact of a relatively understudied climate change variable, salinity, in comparison to elevated carbon dioxide concentration in coastal crustaceans. We demonstrated that ion transporting capacities are of key importance in terms of predicting responses of marine species to climate change. Mechanisms of active gill ion uptake, which enable euryhaline osmoregulating crabs to invade and exploit estuarine environments have also improved their tolerances to elevated carbon dioxide. By contrast, the failure to increase gill ion transporting capacities in the osmoconforming species shows greater species sensitivity to elevated carbon dioxide. We concluded that osmoconformers are poorly equipped for changes in seawater carbon dioxide and salinity via the inability to increase ion exchange capacities.