A series of laboratory experiments was performed to measure dissolved organic carbon (DOC) production during herbivorous grazing by heterotrophic protists (ciliate Strombidinopsis acuminatum, dinoflagellate Oxyrrhis marina) and copepods ( Calanus pacificus ). DOC production by phytoplankton was also measured. Experiments were performed in artificial seawater to provide a low DOC background against which changes in DOC concentr...

The abundance, vertical distribution, and feeding of Calanus pacificus females were measured at frequent intervals over 24 h during a March phytoplankton bloom in a temperate fjord. Copepod guts contained high levels of phytoplankton pigment only during the nighttime when copepods were in the upper 50 m. Feeding, however, was not strictly a function of phytoplankton availability because copepods fed equally well in the 25–50‐m...