Algae. 1992; 7(2): 207-211.

The Effect of Low Cobalt and Vitamin B sub(12) Concentrations on Marine Phytoplankton Growth Rates

Won-Ho Yih

Department of Oceanography, Kunsan National University

The growth rates of 8 marine phytoplankton clones were measured in media with different levels of Co and vitamin B sub(12) concentrations. The growth rates of oceanic unicellular cyanobacterium (DC2)and coccolithophore(1386) were quite less limited by low Co or vitamin B sub(12) concentrations than those of the neritic unicellular cyanobacteria (1602 and PF44) and coccolithophore(1178). Three neritic species in other groups than cyanobacterium or coccolithophore, Skeletonema costatum(Grev.) Cleve (SKEL), Prorocentrum minimum(Pavil.) Schiller(EXUV), and Micromonas sp.(2167), were not limited by low concentrations of Co or vitamin B sub(12). The distinctive requirements of high Co conentrations by neritic unicellular cyanobacteria and coccolithophore can play an important role for the controlling of the marine phytoplankton communities.

Keywords : phytoplankton, cobalt, vitamin B sub(12), growth limitation