About the Cruise

Our approach to studying Ocean Acidification (OA) effects on Plankton and the Surface Ocean

 Our approach involves observation of organisms living in the natural environments for which they will clearly be highly adapted. This approach takes advantage of the fact the natural differences in the carbonate chemistry between sites can differ by as much as those associated with a doubling of atmospheric CO2.

An observational approach offers increased realism, both in terms of adaptation (organisms being evolutionary adapted to the in-situ environment they inhabit) and inclusion of all components and levels of the natural ecosystem.  The main weakness is the potential for significant, but potentially hard to defect, effects of confounding factors that co-vary with carbonate chemistry between locations. Observational studies are a valuable complement to laboratory, mesocosm and ship–board experiments because they include chronic effects of OA that may include evolutionary adaptation, changes in the composition of the species assemblage, and also feedbacks and indirect effects that occur within a natural marine ecosystem.

More specifically, we propose a combination of observational data collection and experimental bioassays, thus filling a clear gap with respect to previous and ongoing international research.

During the cruise we will perform about 6 bioassay experiments designed to evaluate the response to artificial carbonate system manipulation of multiple organisms and processes. We will employ separate batches of bioassay bottles targeted at different trophic levels, to evaluate the physiological and trophic responses of marine planktonic prokaryotes, protists and metazoa. Our integrated experimental design will enable the first study of OA effects across a range of different environmental settings. More robust conclusions can thus be drawn on potential ecosystem responses to OA.

Our Method

•  We bring volumes of natural seawater from the ocean surface and place them in a customised laboratory container on deck, and there subject the organisms within to higher CO₂.

• We monitor the changes that take place within these natural communities as the seawater acidity is increased to controlled levels representative of future oceans subjected to moderate and high CO₂ emission rates.

•  We include the natural environmental variability and complexity that is not captured in typical laboratory experiments.

• We examine natural organisms, ecosystems and biogeochemical and climate-relevant variables in the real world, out at sea in places that are naturally more acidic or alkaline.

The expedition, aboard the RRS James Clark Ross, will end on 4^th July, in Reykjavik, Iceland.

The research is part of the UK Ocean Acidification Research Programme (UKOA), funded by the Natural Environment Research Council (NERC), the Department of Environment, Food and Rural Affairs (Defra) and the Department of Energy and Climate Change (DECC).