Effects of the severe winter 1995/96 on the biological oceanography of the Sylt-Rømø tidal basin

Abstract

Water temperature, salinity and precipitation, micronutrients (N, P, Si) and chlorophyll a concentrations in the Sylt-Romo tidal basin (German Bight) deviated between the early 1990s, with mild winters, and the years 1996–1997 with a severe winter and a moderate winter. As a consequence of low temperature, offshore winds and low precipitation in the severe winter 1995/96, salinity peaked in February 1996 and nitrate concentrations were low. The latter further decreased in March as chlorophyll a peaked with an exceptional bloom of the diatom Odontella aurita, probably triggered by low water temperature. Winter temperatures and spring chlorophyll a in the Sylt-Romo tidal basin correlate well with the climatic North Atlantic Oscillation index.