It has long been recognized that the biological productivity of the sea depends primarily upon the nutrition of the phytoplankton. The aim of these experiments was to study this basic process in the cycle of production by the artificial increase of those plant nutrients most likely to become limiting....
Pratt, David M.. 1949. "Experiments in the fertilization of a salt water pond." Journal of Marine Research 8, (1). https://elischolar.library.yale.edu/journal_of_marine_research/703