Cruise report from R/V Aranda week 45-46, 2018

Type: Report
Author: Johan Kronsell


In large parts of the deep water in the Baltic Proper the oxygen concentration was close to zero. Anoxic conditions, when hydrogen sulphide can form, were found in both the Western and the Eastern Gotland Basin from 80-90 meters depth. In the Bornholm Basin the oxygen concentration went down to 0.4 ml/l and in the Arkona Basin the lowest measured value was 3.3 ml/l.

Nutrients in the surface water varied, and both in the Baltic Proper and the western sea areas, concentrations ranged from below normal for the season to above normal. The silicate concentrations in the surface water were still above normal in the Baltic Proper but in the Skagerrak and the Kattegat there were normal concentrations.

The sea surface temperature was generally normal for the season, in the Skagerrak and the Kattegat close to 10°C and in the Baltic Proper from just below 8°C in the north western parts to about 11°C at BSCIII-10 in the south east. The salinity in the sea surface was normal for the season or above normal, except for the Sound, where it was below normal.