Zinc and cobalt are essential trace metals for phytoplankton growth and can substitute for each other metabolically in some eukaryotic algal species, especially in some marine diatoms and coccolithophorids. In the present study, it is reported that in the marine diatom Chaetoceros calcitrans , Co cannot replace Zn: in contrast, Co substitution of Zn was found in Emiliania huxleyi . It is concluded that Co can substitute for Zn...

Blooms of large diatoms dominate the CO 2 drawdown and silicon cycle of the Southern Ocean in both the past and present. The growth of these Antarctic diatoms is limited by availability of iron (and light). Here we report the first assessment of growth rates in relation to iron availability of two truly oceanic Antarctic diatom species, the large, chain‐forming diatom Chaetoceros dichaeta and the small, unicellular diatom C. b...