Phytoplankton and nutrients in the waters north-west of Spitsbergen in the autumn of 1979

Abstract

Phytoplankton biomass, primary production rates and inorganic nutrients were measured in the uppermost layer of the ice-edge region and in open water and compared with environmental factors during a three-week cruise in September – October 1979. Biomass and production values were low (maximum 2.2 μg chl a l⁻¹, 2.5 mg C m⁻³ h⁻¹). A post-bloom community of diatoms, consisting mainly of representatives of Chaetoceros, Leptocylindrus, Nitzschia and Thalassiosira, was predominant. Concentrations of phosphate were quite low (maximum 0.55 μM I⁻¹). Nitrate and silicate ranged from no measurable quantities to 5.7 μM l⁻¹ and 3.8 μM l⁻¹, respectively. The possibility of light and nutrient limitation on phytoplankton growth is discussed.