Middle East Technical University, Institute of Marine Science, Turkey
Involved Scientists: Dr. Mustafa Mantıkcı, Melike Kazak

The Sea of Marmara is a highly eutrophic basin that connects the Mediterranean Sea and the Black Sea via Turkish straits. The anthropogenic stress on the Sea of Marmara ecosystem have been increasing over decades causing higher risk of anoxia at the bottom water. Primary production is limited to less saline upper Black Sea originated water, however, degradation of particulate organic matter originated from photic zone causes depletion of dissolved oxygen and result in deoxygenation and nutrient enrichment of Mediterranean originated sub-halocline water. Furthermore, mucilage formation observed at spring and summer 2021 caused enhanced bulk of organic carbon production. Effect of mucilage on oxygen consumption is studied in this project.

Set-Up and Study Site

Water samples, taken from the photic zone (including halocline) of 10 stations representing the Sea of Marmara, were incubated at in-situ temperature for 4 hours, and their oxygen consumption was monitored. Sub-halocline water samples taken from the same stations are incubated in accordance with in-situ conditions, long-term (6-7 weeks) discrete oxygen measurements are done. For the production experiments, surface water samples from 7 stations are incubated at in-situ temperatures at 8 different light intensity levels (16-963 μmol photons m^-2 s^-1) with LEDs.