Summary of the Swedish National Marine Monitoring 2016 - Hydrography, nutrients and phytoplankton

Type: Report
Series: RO 60
Author: Karin Wesslander, Lena Viktorsson


Results from the Swedish national marine monitoring in the pelagic during 2016 are presented. The institutes who conduct the national monitoring are SMHI (Swedish meteorological and hydrological institute), SU (Stockholm University) and UMF (Umeå marine sciences centre). The presented parameters in this report are; salinity, temperature, oxygen, dissolved inorganic phosphorous, total phosphorous, dissolved inorganic nitrogen, total nitrogen, dissolved silica, chlorophyll and phytoplankton. Secchi depth, zooplankton, humus, primary production, pH and alkalinity are also measured but not presented. Seasonal plots for surface waters are presented in Appendix I.  Time series for surface waters (0-10 m) and bottom waters are presented in Appendix II. The amount of nutrients in the sub-basins of the Baltic Sea is presented per season and year in Appendix III.

Exceptional events 2016 

  • A warm September due to several high pressure systems, with temperatures more than one standard deviation above mean in almost all stations from Skagerrak, Kattegat and the Baltic Proper.
  • Low oxygen in Kattegat bottom water during autumn as can be seen in the seasonal plots for both Anholt E and Fladen.
  • Improved oxygen condition in the East Gotland Basin, due to an increased frequency of deep water inflows in comparison to the period 1983 until the large inflow in December 2014. The inflow of 30 km3 in the beginning of the year could be tracked in the deep water in the Eastern Gotland Basin in June.
  •  Elevated levels of silicate have been observed in the Baltic Sea since 2014 and the silicate levels were also elevated this year but mainly in the central and the northern parts of the Baltic Proper.
  • In July there were high cell numbers of the dinoflagellate Dinophysis acuminata, which caused high levels of toxins in blue mussels. During this period it was forbidden to harvest blue mussels along the Bohus coast.
  • Unusual long period of cyanobacteria bloom in the Baltic Sea.