Southern Belt Sea; Western Baltic Proper and, from 1975, the Sound, Kattegat and Great Belt

Excretion rate parameters in the water column

Ancient oxygen data from the southern Belt Sea and western Baltic Proper have been compiled by the Danish Institute for Fishery and Marine Research. Even though the measurements have not been conducted regularly, it is possible to compare the oxygen conditions in different periods: 1902-12, 1926-38, 1949-59, 1973-79 and 1980-90. Since 1975 oxygen concentrations have been measured at standard depths at about 25 stations in the Sound, Kattegat, Belt Sea and western Baltic Proper 6-12 times per year. As all the oxygen measurements have been made by Winkler titration, the comparability and accuracy of all data is good. The time series show a decrease in the oxygen concentration in autumn after the 1950s. In the 1980s serious oxygen depletion has nearly annually been observed in the area from the southern Kattegat to the western Baltic Proper.

Aarhus University, Department of Bioscience, Marine Ecology Roskilde
399 Frederiksborgvej P.O. Box 358
Roskilde

DK-4000
Denmark