Nutrients limiting the production of phytoplankton in the Sargasso sea, with special reference to iron

Abstract

The effects of enriching surface water samples from the Sargasso Sea upon the rate of C¹⁴ assimilation was investigated. The addition of nitrate, phosphate and vitamins, added separately or in combination, had no stimulatory effect, while addition of a trace metal mixture increased C¹⁴ uptake by several-fold. The effective component of the trace metal mix found to be iron, which alone enhanced C¹⁴ uptake for 24 hours but which required the addition of nitrogen and phosphorus to produce a comparable effect of over a three-day period.