Cruise report from R/V Aranda week 49-50, 2018

Type: Report
Author: Johan Kronsell


In large parts of the Baltic Proper, the oxygen concentration in the deep water was close to zero. Anoxic conditions, when hydrogen sulphide can form, were found at all stations sampled in the Western and Eastern Gotland Basin. The depths where hydrogen sulphide were first detected at the visited stations varied between 85-125 meters. In the Bornholm Basin, the Bight of Hanö and at the station BCSIII-10 in the south eastern part of the Baltic Proper, acute hypoxia (oxygen < 2ml/l) was found from about 70 meters depth.

The measured nutrients in the surface water of the Skagerrak and the Kattegat were generally below normal levels for the season, except for silicate concentrations in the Kattegat, where levels were normal. In the northern part of the Baltic Proper the concentrations of silicate and dissolved inorganic phosphorus (DIP) where above normal levels in the surface water, in the southern part the levels were normal. The surface concentration of dissolved inorganic nitrogen (DIN) was normal for the season at most stations in the Baltic Proper.