ABSTRACT There is mounting evidence that the very low oceanic inputs of some essential trace elements may limit the ability of primary producers to acquire major nutrients and grow. This this project the principal investigator will test the hypotheses that (1) low zinc concentrations in the surface oceans may limit the rate of inorganic carbon uptake by phytoplankton; (2) that cadmium and cobalt may substitute for zinc in some species; and that (3) the relative availability of carbon, zinc, cadmium, and cobalt may effect differentially the growth of diatoms and coccolithophores and thus influence through the so-called rain ratio (calcium carbonate/organic carbon export to the deep sea), the efficiency of the biological carbon dioxide pump and hence the partial pressure of carbon dioxide in surface seawater. These hypotheses will be studied using laboratory experiments with diatoms and coccolithophores and groundtruthed through a small sea-going field program.
