Occurrence of Iron in the Sargasso Sea Off Bermuda1

Data are presented showing the concentration of particulate and soluble iron in the Sargasso Sea near Bermuda over the period of one year. The ratio of these two fractions was roughly 1 : 1, no seasonal cycle was noted in their concentration, and the distribution of total iron was homogeneous in vertical section. In spite of the fact that previous experimental evidence has shown iron to be a primary limiting factor to phytoplankton growth, no correlation between iron concentration and primary production was apparent.