Baltic Earth Working Group on Salinity dynamics in the Baltic Sea

Background and objective

The salinity in the Baltic Sea is not a mere oceanographic topic but involves the complete water and energy cycle. It is also an elementary factor controlling the ecosystems of the Baltic Sea. The salinity dynamics is controlled by net precipitation, river runoff and the compensating inflow of higher saline waters from the Kattegat. Furthermore, due to the expected increase in precipitation, first studies of future development indicate even 2‐3 PSU decrease in salinity to the end of the century. Since the Baltic Sea ecosystem has adapted to the present salinity regime, expected changes would exert an enormous stress on marine fauna and flora with associated negative socialeconomic consequences for the Baltic Sea countries. The present understanding of salinity changes is still very limited, and future projections of the salinity evolution are rather uncertain. More detailed investigations on regional precipitation patterns (runoff), atmospheric variability (wind), highly saline water inflows, the exchange between the subbasins and turbulent mixing processes are still needed. Furthermore, there is also a need for new climate projections simulations with improved atmospheric and oceanographic (coupled) model systems. Suggested key research areas are the interrelation between decadal/climate variability and salinity, water mass exchange and major Baltic inflows (do we understand the dynamics of the present‐day salinity distribution, can we predict MBIs?), detailed studies on the regional salinity distribution/variability and associated circulation patterns (including salinity fluxes between the coastal areas and the open sea and within the sub‐basins).

Description of tasks (or Terms of Reference)

Potential activities include both observation and modelling. Dedicated research cruises like the ones performed during the 2014-2016 inflow period, and the deployment of moorings to measure e.g. salinity, oxygen and currents are needed to improve the inventory of observational data. Modelling activities using new model approaches, the calculation of salinity budgets and process studies should help to understand advection and diffusion of saltwater in the Baltic Sea. Review articles will summarize the current state of knowledge, and workshops and special sessions at conferences (e.g. on the recent inflow events) shall promote the communication and exchange of ideas and results.

Members of the Working Group on the Salinity of the Baltic Sea (as of June 2016)

Andreas Lehmann (Chair)GEOMAR,
Kai MyrbergFMI,
Piia PostUniversity of
Markus MeierIOWGermany