Abstract
The effect of added organic substrates on the growth characteristics, photosynthetic O2 evolution, and dark survival of the marine phytoplankton Thalassiosira pseudonana, Dunaliella primolecta and Chlamydomonas euryale was studied. Only in the case of T. pseudonana did the addition of organic substrates decrease O2 production and prolong dark survival; in the other algae no such changes were observed.