The results of a preliminary experiment suggested that a complexed
form of cobalt was more efficacious in promoting growth of a
marine phytoplankton than ionic cobalt. The phytoplankton used in this
experiment was Coccolithus huxleyi, a vitamin B₁₂ producer, and the
cobalt complex was cobalt (II)- ethylenediaminetetracetic acid [Co(II)-
EDTA]....