**2.1.3 The Sea of Marmara**

The Istanbul Strait connects the Sea of Marmara to the Black Sea and the Canakkale Strait to the Aegean Sea. The Sea of Marmara separates Turkey's Asian and European regions. Being an important water route between the Mediterranean and the Black Sea, the Sea of Marmara is under the pressure of heavy marine transportation. The Sea of Marmara is under the influence of various anthropological factors such as dwelling, domestic and industrial wastes. The bacteria which come from ships' ballast water are another effective factor on the composition and abundance of bacteria in the Sea of Marmara. The less saline waters of the Black Sea reach the Mediterranean via upper currents while the concentrated saline waters of the Mediterranean reach the Black Sea via the undercurrents of the Canakkale and Istanbul Straits. These interesting hydrodynamic characteristics of the Sea of Marmara offer us unique opportunities for researching bacterial composition, under different, poorly described conditions.
