Pelagic plankton diel vertical movement, diversity, and density in relation to nitrate concentration in Bonaire, Dutch Caribbean

Plankton are the base of the marine food web and are studied for a broad range of research relating to diversity and ocean health. These organisms have not been well studied in Bonaire and this study provided a preliminary assessment for the pelagic net plankton movement and diversity. Water samples and plankton tows were collected using a Niskin bottle and 20-micrometer closable plankton net respectively at four depths: 90 m, 60 m, 30 m, and 10 m. The water samples were processed for nitrate concentration and the 5-meter vertical plankton tows were analyzed for plankton abundance using the following categories: diatoms, dinoflagellates, copepods, and other zooplankton. Dinoflagellates displayed diel vertical migration with higher density at 10 m and 30 m during the day and lower density at 10 m and 30 m at night. Simpson’s Diversity Index (SDI) did not show a significant difference in the diversity at 90 m and 10 m during the day or night. Nitrate concentration and plankton density were not found to be correlated. This study created a preliminary assessment for further research into the effects of the lunar cycle, nitrate, and movement of the pelagic net plankton of Bonaire.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 28-34 from CIEE Bonaire.