7 
DISTRIBUTION OF NUTRIENT CONCENTRATIONS, SALINITY AND TEMPERATURE IN THE 
GERMAN BIGHT 
For the chemical-oceanographical investigations in 1936, only surface samples were analysed. The 
maps (figs. 1-4) show, compared with the open sea, slightly elevated nutrient concentrations near 
the coast. Besides, nitrite has a secondary maximum near the convergence zone. 
In 1978 and 1985 to 1990, the concentration gradients are much more marked (figs. 7 and following): 
high concentrations with low salinity near the coast; lower concentrations in water with a greater 
salinity. The near surface samples were taken from 5 m depth, in 1978 and 1985 also from 1 to 2 m 
depth. In this case the mean value of both sampling depths is plotted in the maps. 
For the investigations since 1978 also samples from other water depths were analysed. With only few 
exceptions the concentration differences are so negligible that an extra plotting seemed to be superflu 
ous. 
More or less great differences are seen in the salinity and nutrient distribution in individual areas 
depending on medium-term weather conditions. In mild winter months when winds mainly come 
from the southwest, such as in January/February 1989 and 1990, a very distinct fresh water plume 
with a high concentration of nutrients moves along the coast of Schleswig-Holstein. In cold winter 
months when winds mainly come from the east, such as in January/February 1985 and 1987, the 
fresh water part here is smaller and the water contains a considerably lower concentration of nutrients. 
Just how different water can be at the same site at different times is shown using the position 54° 
50' off Sylt: in February 1989, salinity here was only 27.51. If pure North Sea water is assumed to 
have a salinity level of 35, this would mean a fresh water part of 21.4%. In 1987, salinity was 30.56 
and in 1985 30.52, a fresh water part of only 12.7%. At present the nutrient concentrations in the 
inflowing frehwater are about 30 times higher than in the North Sea water. Therefore such differences 
in the mixture ratios must result in very different nutrient concentrations. 
Nutrient concentrations measured at different times at the same site cannot be compared for trend 
analysis; only those measured in water bodies with the same proportions of salt and fresh water can 
be compared. Methods and results of the comparative evaluation of the data presented here, are 
published in the Deutsche Hydrographische Zeitschrift (Korner und Weichart, 1991).