PHYTOPLANKTON PRODUCTION IN THE SARGASSO SEA AS DETERMINED USING OPTICAL MOORING DATA

Optical measurements from an untended mooring provide high-frequency o bservations of in-water optical properties and permit the estimation o f important biological parameters continuously as a function of time. A 9-month time series, composed of three separate deployments, of opti cal data from the BIOWATT 1987 deep-sea mooring located in the oligotr ophic waters of the Sargasso Sea at 34-degrees-N, 70-degrees-W are pre sented. These data have been tested using several bio-optical models f or the purpose of providing a continuous estimate of phytoplankton pro ductivity. The data are discussed in the context of contemporaneous sh ipboard observations and for future ocean color satellite observations . We present a continuous estimation of phytoplankton productivity for the 9-month time series. Results from the first 70-day deployment are emphasized to demonstrate the utility of optical observations as prox y measures of biological parameters, to present preliminary analysis, and to compare our bio-optical observations with concurrent physical o bservations. The bio-optical features show variation in response to ph ysical forcings including diel variations of incident solar irradiance , episodic changes corresponding to wind forcing, variability caused b y advective mesoscale eddy events in the vicinity of the mooring, and seasonal variability corresponding to changes in solar radiation, shoa ling of the mixed layer depth, and succession of phytoplankton populat ions.