5 
INTRODUCTION 
In winter months the distribution of nutrient concentrations in the German Bight is mainly determined 
by the mixture of nutrient-rich fresh water and North Sea water. Then, the biochemically caused 
variability of the nutrient concentrations is at its lowest. The nutrient consumption by phytoplankton 
in the euphotic layer is negligibly low; the degradation of organic material in the water column and 
at the interface between water and sediment should also largely be completed, especially in January 
and February. Moreover, stormy weather provides for vertical mixing and equalization of vertical 
concentration differences in nutrients. 
So, with few exceptions, the winter season is suitable to look for concentration changes (or trends) 
caused by different inputs. 
As early as January/February 1936, Kalle (1937) measured nutrient concentrations in the entire 
German Bight as part of an oceanographic research programme. Encouraged by the beginning of 
discussion about eutrophication, Weichart (1986) carried out nutrient measurements in January 1978. 
Compared with 1936, the phosphate concentration showed a strong increase, by a factor of 3 to 4 in 
near-coastal areas, by a factor of 2 in the central part of the German Bight. During the same time 
interval the silicate concentration had increased only little. No increase - whether in phosphate nor 
in silicate could be found in the northeastern part of the German Bight. 
Measurements at the end of January/beginning of February 1985, at the end of January 1987, at the 
beginning of February 1989 and in January 1990 did not show any further increase of the nutrient 
concentrations (Korner und Weichart, 1991). 
In this publication the measurements mentioned above, are represented in maps, showing the distribu 
tion of nutrient concentrations, salinity and temperature in the German Bight.