In this study, the number of bacteria, zooflagellates, cliates and biomass amount in the
Marmara Sea are presented.
The total bacteria in surface waters of Marmara Sea is approximately 2x106 cell mL-1, the maximum number of bacteria was recorded at a station in the northern Marmara Sea as 4.96x10 6 cell mL-1 and the lowest number of bacteria was recorded in the western part of Marmara Sea near the Dardanelles as 0.60106 cell mL-1.
The average volume of planktonic bacteria in the surface waters of the Marmara Sea is
0.11 3, however this amount was recorded 2-3 times more in same stations where
Ctenophora mucus density is high (in the second station 12 m. depth 0.3 \ The average
of microbial biomass in the surface layer was recorded 232 mg m -3, from pycnocline till
60 m. 26 mg m-3 and deeper than 60 m. 18 mg m -3.
The number of zoo flagellates in the surface layers as 4x 106 cell L- 1, biomass as 50 mg
m-3, ciliates as 13x!03 cell L-1 and average biomass amount as 75 mg m -3 were
calculated. The average microbial decomposition amount in the surface was calculated as
0.15 mg o2L!day. It was seen that, there is too much pollution around the Bosphorus and
the northern parts of the Marmara Sea has a eutrophic sea character because of the polluted
waters of the Black Sea.
The microbiological production in the surface layers of the Marmara Sea shows
similarity to the records of the mesotrophic waters of the Black Sea. In the deep waters of
the Marmara waters there is a problem of oxygen deficiency because of the fast oxidation
ofH2S. The turnover time of labile organic matter in the surface layer was recorded as 40-60
days. Between summer and autumn in the surface water of the Marmara Sea there is 2-4 mg
C m-3 labile organic matter and in the deep Mediterranean waters there is 1.2 mg C m -3
labile organic matter. Presently anoxia in deep waters is being prevented via aeration by the
oxygenated Mediterranean waters entering through Dardanells.