The research interests of EPOCA  are divided into four themes.

First, EPOCA aims to document the changes in ocean chemistry and geographical distribution of marine organisms across space and time. Paleo-reconstruction methods are used on several archives, including foraminifera and deep-sea corals, to determine the past variability in ocean chemistry (carbonate, nutrients and trace metals) and to tie these to present-day chemical and biological observations.

Second, EPOCA devotes much efforts to quantifying the impact of ocean acidification on marine organisms and ecosystems. Key climate-relevant biogeochemical processes such as calcification, primary production and nitrogen fixation are investigated using a large array of techniques, ranging from molecular tools to physiological and ecological approaches. Perturbation experiments are carried out both in the laboratory and in the field. Key organisms are selected on the basis of their ecological, biogeochemical or socio-economic importance.

Third, the modelling component of EPOCA integrates the chemical, biological and biogeochemical impacts of ocean acidification into biogeochemical, sediment and coupled ocean-climate models. Special attention is paied to feedbacks of physiological changes on the carbon, nitrogen, sulfur and iron cycles and in turn how these changes will affect and be affected by future climate change.

Finally, EPOCA assesses uncertainties, risks and thresholds ("tipping points") related to ocean acidification at molecular, cellular, organismal, local and global scales. It also assesses pathways of CO2 emissions required to avoid the identified thresholds and describe the state change if these emissions are exceeded and the subsequent risk to the marine environment and Earth system.

This ambitious mission relies on combining the strong EPOCA consortium of 27 partners, including more than 100 leading European scientists, and their field and laboratory resources. EPOCA coordinates with major national and international projects and programmes.