Chlorophyll-a is an indicator of phytoplankton biomass and performs photosynthesis. This mechanism provides for the production of primary organic matter in the nutrient cycle. The organic load and organic wastes generated in the euphotic zone and produced in the connected productions settle deeper in the water column. In the meantime, they consume the oxygen dissolved in the water and, through bacterial degradation, reduce the oxygen required for life.

The Laboratory, Measurement and Monitoring Department of the Ministry of Environment and Urbanization implemented the “Integrated Marine Pollution Monitoring Program” under the coordination of the TUBITAK-Marmara Research Center

Under this program, the quality and pollution status of our seas are determined based on various indicators through monitoring studies in the Mediterranean Sea, the Aegean Sea, the Sea of Marmara and the Black Sea.

Marine pollution and quality are assessed on the basis of water management units (WMUs). Water Management Units, or Coastal Water Bodies, define a section of surface water delineated by important surface water characteristics such as physical, hydromorphological, ecological, and loading analyses. They are the smallest management units covered by the Water Framework Directive.

The highest chlorophyll-a levels were observed in shallow and less saline coastal areas fed by rivers and other terrestrial inputs such as domestic/urban wastewater (AKD-1 (Asi River), AKD-4 (Ceyhan River), AKD-5 (Seyhan River)) in the Mediterranean Sea. Chlorophyll-a levels were low and at their natural levels in the surface waters of the open sea, where the effects of terrestrial inputs were attenuated, and in the clean coastalzone (region between Anamurand Marmaris). The effects of terrestrial inputs in the water column extended to 5-10 m depth. The variation of the 2019 summer period values with depth was investigated. Accordingly, high values of the biomass indicator Chl-a were measured in the coastal areas of the gulfs of Mersin and İskenderun, which are fed by rivers and where low salinity and Secchi Disc Depth values were observed. On the other hand, Chl-a values were in the lower range in the surface waters of the coastal area and the reference zone, where terrestrial inputs were lower (Graph 62).

In the assessment of surface layer chlorophyll-a concentrations in the Aegean Sea 2014-2019 WMUs, although no significant differences were observed between summer and winter sampling, relatively high values were observed in the Inner and Central Gulf of İzmir and the Gulf of Güllük. Relatively high values in the northern Aegean during the winter months probably originate from the Sea of Marmara (Graph 63).

Analysis of the surface distribution of chlorophyll-a in winter and summer 2019 shows that concentrations in the entire Black Sea are 0.4-3.6 µg / L in summer and 0.1-8.9 µg/L in winter. Relatively higher values (˜ 3.0 µg / L) were generally measured between Rize and Samsun in winter and only in Samsun in summer (TRKSK1: 8.9 µg / L). Most of the open stations remainedunder

These two periods (especially the spring period) had high values in almost all WMUs in the Marmara Sea during winter and spring 2019. Concentrations in summer 2019 are consistent with previous summer concentrations (Graph 65).

GRAPH 62- 2014-2019 COMPARISON OF THE MEDITERRANEAN SURFACE WATER CHLOROPHILE-A CONCENTRATIONS

Source: MOEUCC-DG for EIA, Permitting and Inspection and TÜBİTAK-MAM (2019). Integrated Pollution Monito- ring Project (2017-2019). ÇTÜE 5178702, Report No. ÇTÜE.17.2111 (The Mediterranean Final Report, 2019), February 2019, Gebze-Kocaeli.

GRAPH 63- 2014-2019 COMPARISON OF THE EAGEAN SURFACE WATER CHLOROPHILE-A CONCENTRATIONS

Source: MOEUCC-DG for EIA, Permitting and Inspection and TÜBİTAK-MAM (2019). Integrated Pollution Monitoring Project (2017-2019). ÇTÜE 5178702, Report No. ÇTÜE.17.2113 (The Aegean Sea Final Report, 2019), February 2019, Gebze-Kocaeli

GRAPH 64- 2014-2019 COMPARISON OF THE BLACK SEA SURFACE WATER CHLOROPHILE-A CONCENTRATIONS

Source: MOEUCC-DG for EIA, Permitting and Inspection and TÜBİTAK-MAM (2019). Integrated Pollution Monitoring Project (2017-2019). ÇTÜE 5178702, Report No. ÇTÜE.17.2115 (The Black Sea Final Report, 2019), February 2019, Gebze-Kocaeli.

GRAPH 65- 2014-2019 COMPARISON OF THE MARMARA SEA SURFACE WATER CHLOROPHILE-A CONCENTRATIONS

Source: MOEUCC-DG for EIA, Permitting and Inspection and TÜBİTAK-MAM (2019). Integrated Pollution Monito- ring Project (2017-2019). ÇTÜE 5178702, Report No. ÇTÜE.17.2116 ( The Marmara Sea Final Report, 2019), February 2019, Gebze-Kocaeli