Report: Gunni Ærtebjerg
Cruise leader: Gunni Ærtebjerg/Kjeld Sauerberg
Participants: 7-15/2: Gunni Ærtebjerg, Hanne Ferdinand, Peter Kofoed;
                      7-18/2: Kjeld Sauerberg, Dorete Jensen, Lars Renvald, Jan Damgaard;
                      7/2     : Ole Lund Jensen

This report is based on preliminary data, which might later be corrected. Citation permitted only when quoting is evident. This file contains the summary only. To get the full report, click here. This file is in Adobe Acrobat ™ format. If you do not have a a Adobe Acrobat ™ Reader, click here, to download

Summary

The unusually high wind activity during this winter had mixed the water column well. Practically no stratification was present in the North Sea, and the inner Danish waters were unusually homogenous. In the Arkona Sea a primary halocline was found at 39 m depth due to saline bottom water flowing in from the Sound and Belt Sea. A pycnocline was also present in the deeper parts of the Kattegat, but relatively weak and generally situated in more than 20 m depth.

The surface temperature was relatively high due to the mild winter. In the inner Danish waters both the water temperature and salinity was higher than long term means for February in the whole water column, except for lower bottom water temperature and salinity in the southern Kattegat.

In the North Sea the inverse linear relationship between salinity and nutrients (except for nitrite) was as usually observed mirroring the river based nutrient load to the south-eastern North Sea. The Jutland Coastal Current with relatively low temperature and salinity, and high nutrient concentrations was narrow along the Danish coast up to Hanstholm at the entrance to the Skagerrak and could be traced at Hirtshals, but not in the Kattegat.

In the western Kattegat relatively high nitrate concentrations of 10-13 m mol/l not originating from the North Sea was observed. In the Arkona Sea the nitrate concentration in the surface was 3.8-4.9 m mol/l. In the rest of the inner Danish waters the nitrate concentrations were between 7 and 9 m mol/l in the whole water column.

The phytoplankton spring bloom had not yet started in any area. The minimum oxygen concentrations were high and most often close to saturation.