We performed an experiment in the Baltic Sea in order to investigate the consequences of the increasing CO2
levels on biological processes in the free water mass. There was more accumulation of organic carbon at high CO2
levels. Surprisingly, this was caused by reduced loss processes (respiration and bacterial production) in a high-CO2
environment, and not by increased photosynthetic fixation of CO2
. Our carbon budget can be used to better disentangle the effects of ocean acidification.