Cruise report from KBV 002 Triton week 25, 2013

Type: Report
Author: Anna-Kerstin Thell


The surface water temperatures were normal in the investigated area, except for in the south-eastern Baltic were the temperature was slightly above normal. The surface salinity in the north-western part was slightly lower than average, in the remaining areas close to normal. In the surface all nutrient concentrations were as expected for this time of year, except for the lower than normal silicate in the eastern Gotland Basin. At depths greater than 80 metres the oxygen concentrations dropped below 2 ml/l in the major part of the area, except for in the very south-east. In the eastern Gotland Basin hydrogen sulphide was observed from about 125 metres depth, and in the western part already from 90 metres and below. The hydrogen sulphide concentrations in the deep water were still high, though not as elevated as observed during the preceding expedition. In the south-eastern part, at station BCS III-10, a relatively strong bloom, supposedly consisting of cyanobacteria, was observed. Fluorescence measurement indicated plankton activity in the whole area.