Plankton collections and bottom hauls made during the 1935 expedition of the "Atlantis" to the Gulf of Mexico suggested that there is a zone of high productivity in the shallow water area near the mouth of the Mississippi, and since the effect of river outflow on ocean life is a phase of marine biology which has not yet received adequate attention, further investigation seemed desirable.
Riley, Gordon A.. 1937. "The significance of the Mississippi River Drainage for biological conditions in the Northern Gulf of Mexico." Journal of Marine Research 1, (1). https://elischolar.library.yale.edu/journal_of_marine_research/519