A Study of Phytoplankton in the Lesser Antilles Region

In a marine biological survey of the Antillean region between Puerto Rico and Trinidad, 205 species of net phytoplankton were identified. Benthic organisms were more often observed at “downstream” stations near islands, where chlorophyll values averaged 0.38 mg m⁻³ at 16 stations as compared with an average of 0.11 mg m⁻³ at 30 “upstream” stations. Growth of phytoplankton was generally limited by low nutrients (average nitrate 0.18 µg-at l⁻¹ and phosphate 0.08 µg-at l⁻¹ at surface stations) in the thermally stratified 120-meter photic zone. More abundant phytoplankton and nutrients near Trinidad are apparently related to land drainage and strong westerly currents.