Phytoplankton production and adaptation in the vicinity of Pemba and Zanzibar islands, Tanzania

Abstract

Phytoplankton production and physiology were investigated at six selected locations during a research cruise in early October 2007 in Tanzanian coastal waters. The dataset included photosynthesis– irradiance and active fluorescence parameters, phytoplankton absorption coefficients, and pigment concentrations. Primary production was estimated to vary over the range 0.79–1.89 g C m⁻² d⁻¹. Diagnostic pigments indicated that micro–nanophytoplankton comprised the communities at three stations and nano–picoplankton at the other three stations. At all stations, the populations maximised their photosynthesis in the upper water column under elevated irradiance and low nutrient conditions. Significant photosynthetic activity was also observed at depth under very low light where the communities increased their quantum yield of photochemistry and the proportion of accessory chlorophylls b and c and photosynthetic carotenoids.

Keywords:

• physiological adaptation
• primary production
• Tanzania coastal waters