Expeditionsrapporter från utsjöövervakningen

During the first part of the expedition the weather was dominated by strong winds, reaching storm strength in the Baltic. The second part was dominated by weak to moderate winds. The nutrients showed normal values in the surface water in the whole area. Hydrogen sulphide was detected in the Gotland …

The surface water temperatures varied between 12 -13 degrees in the Skagerrak-Kattegat area and between 10.5-12.5 in the Baltic Proper. The surface layer was depleted of nitrate and the rest of the nutrients showed low values in the Skagerrak-Kattegat. The oxygen situation in the Kattegat deep …

In the Kattegat phytoplankton sampling according to BMP was performed. Maxima of fluorescence were seen in the Kattegat below the halocline at about 20 m and in the Sound at about 10 m. Almost all over the area there were low concentrations of phosphate and depletion of nitrite and nitrate. …

In certain areas of the Baltic proper strong blooms of potentially toxic bluegreen algae (Nodularia) and dinoflagellates were observered. The observations were supported by sharp fluorescence maxima in the water. The extent of oxygen depleted, sulphidic, bottom water in the Gotland Basin had …

In the eastern Skagerrak there were a bloom of a flagellate, Emiliania Huxlley, which gave the surface water a turkos colour and caused low visibility with secchii depths <3m. The surface temperatures varied between 14-15 deg in the Skagerrak-Kattegatt and between 11-13 in the Baltic Proper. The surface layer was generally depleted of nutrients. Fluorocens measurements indicated a subsurface bloom in the whole area between 10 and 20 depth. Continuously measurements of fluorocens at 4 m depth showed highest values just outside of Skagen and in the eastern Gotland basin. There were low oxygen values (< 2ml/l) below 70-100 m depth in the Bornholm basin, the Hanö bight and in the basins east, north and west of Gotland. Hydrogen sulphide was only measured in the Hanö bight at 75m depth and in the eastern Gotland basin, at 240 m depth in the Gotland deep and at 195 m in the Fårö deep.

Surface water concentrations of nutrients, as well as fluorescence, were low for the time of the year, and the oxygen saturation was of the order 103-105%. The surface water temperatures, which earlier, after the long winter, have been below normal, were again back to average levels (4-5°C). The …