Carbon : nitrogen ratios of Baltic Sea copepods - indication of mineral limitation? Short Communications

The carbon (C) and nitrogen (N) content and the C:N ratio of two common calanoid copepods, Eurytemora affinis and Acartia bifilosa, were measured during spring and summer at the SW coast of Finland, northern Baltic Sea. The C:N ratio of both copepod species was low and stable (4-4.5), irrespective of sampling time, which implies N limitation at least during intermediate to high food concentrations in spring and early summer. In addition, experiments were conducted to reveal whether the diet of copepods affects their C and N content. Adding green algae Brachiomonas submarina in concentrations of 50-500 mu g C l(-1) to