Cruise report from R/V Argos week 16, 1997

Type: Report
Author: Lars Edler, Bengt Yhlen


Skagerrak: The surface temperatures varied between 5.5 and 5.9 oC. The nutrients concentrations above the halocline showed, for the season, normal values. Kattegat and the Sound: The surface salinity was higher than normal.The pycnocline started between 4 and 15 metres depth and was weakly developed.. The surface temperatures varied between 5.0oC in the east and 5.8oC in northwest.The nutrients concentrations showed, for the season, normal values. Phytoplankton was characterized by a post bloom situation. The Baltic Proper: The surface temperature was 4,2 oC in the south and decreased to 1.9oC in the north. All nutrients showed for the season normal concentrations. The nitrate concentration above the halocline was zero in the Arkona and Bornholm Basins and in the Hanö Bight. The oxygen conditions in the bottom water are displayed in a figure. In the Bornholm Basin at BY4, where 6.1 ml/l oxygen was found in the bottom water in the middle of March, the concentration had now decreased to 2.0 ml/l The oxygenated water had moved eastward to BY5 where bottom oxygen concentration had increased from 0.6 to 2.9 ml/L. Hydrogen sulphide was found in the Gotland Deep from 190 metres and downwards and at BY10 at 140 meter. In the Arkona and Bornholm Basins the spring bloom was in progress. In the Eastern, Western and Nothern Gotland Basins the spring bloom had not yet reached its peak.