Marmara Sea

Understanding how finescale processes interact in water mixing at the interface between Black Sea water and Mediterranean Sea water.

The Marmara Sea is  characterized by peculiar oceanographic processes. Cold, fresh Black Sea water entering through the Bosporus meets warm and salty water of Mediterranean Sea origin flowing in through the Dardanelles Strait. This creates the situation that fresher water is located near the surface and much saltier water near the bottom. The Marmara Sea is highly populated (~22 Mio.) and at risk of large-scale anoxic events caused by severe eutrophication. The overall surface flow is westward from the Bosporus towards the Dardanelles Strait, with well-defined anticyclonic gyres. The upper layer currents respond very rapidly to the direct and indirect effect of wind forcing. This creates a unique environment of strong mesoscale activity, whose finescale dynamics is still poorly known.

The Marmara Sea campaign will improve the characterization of oceanic mesoscale and sub mesoscale features (fronts, meanders, eddies and filaments) through the combined use of in situ and satellite data in synergy with numerical models in this highly inhabited region.

Ship-borne studies will take place for 2×1 week using underway CTDs and ScanFish on institute owned and operated research vessel R/V Bilim 2 during phytoplankton bloom times. Moorings might be deployed, funding permitting. SWOT SSH data will be used in modelling efforts to investigate the impacts of mesoscale eddies on bloom dynamics and consequent anoxic events. The circulation model NEMO coupled to the ERSEM ecosystem model will be used.

The Marmara Sea campaign will contribute to understanding mesoscale and sub mesoscale processes in the Marmara Sea and their influence on bloom dynamics and consequent anoxic events, a phenomenon of growing importance in many of the world seas.

Surface currents (left panel) and relative vorticity ( ζ=vxuy) normalized by Coriolis frequency (f) (right panel) for the Marmara Sea study site with SWOT grid overlaid (black lines). Images were generated using output from a high-resolution MITgcm simulation and are instantaneous snapshots from 1 July 2012.

Principal investigators: B. Fach (, S. Husrevoglu (, H. Orek (

Institutes involved in the campaign: Institute of Marine Science, Middle East Technical University

Contact point for the study site: Bettina Fach (