Sea of Marmara

Sea of Marmara
User:Interiot · CC BY-SA 2.5 · source
Name	Sea of Marmara
Native name	Marmara Denizi
Location	Turkey
Type	Inland sea
Inflow	Bosphorus Strait
Outflow	Dardanelles
Basin countries	Turkey
Length	280 km
Width	80 km
Area	11,350 km2
Max-depth	1,370 m

Sea of Marmara

The Sea of Marmara is an inland sea in northwestern Turkey connecting the Black Sea to the Aegean Sea via the Bosphorus Strait and the Dardanelles. It lies between the Bosphorus Strait and the Dardanelles and is bounded by the Thrace and Anatolia. Important adjacent cities include Istanbul, Çanakkale, Tekirdağ, Bandırma, and Yalova.

Geography

The sea separates Thrace from Marmara Region and is surrounded by provinces such as Edirne, Kırklareli, Istanbul Province, Tekirdağ Province, Çanakkale Province, Balıkesir Province, and Yalova Province. Prominent gulfs and bays include the Gulf of İzmit, the Gulf of Erdek, and the Gulf of Bandırma. Islands and archipelagos include Marmara Island, Avşa Island, Paşalimanı Island, Imrali Island, Büyükada, Kınalıada, Heybeliada, Burgazada and other islands in the Princes' Islands group. Straits and narrows include the Dardanelles and the Bosphorus Strait, while major rivers draining into it include the Sakarya River and smaller streams from the Uludağ foothills and the Istanbul Province watershed.

Geology and Bathymetry

The basin sits on the North Anatolian Fault and has been shaped by tectonics involving the Eurasian Plate, the Anatolian Plate, and the Aegean Sea Plate. The bathymetry features several deep basins reaching depths over 1,300 m and shallow shelves near the Gulf of İzmit and the Sea of Marmara islands. Submarine geomorphology includes submerged canyons, fault scarps, and the North Anatolian Fault Zone rupture traces that produced major earthquakes such as the 1999 İzmit earthquake and historical events like the Marmara earthquake of 1766. Volcanic and sedimentary records relate to episodes recorded in cores correlated with studies in the Mediterranean Sea, Black Sea and Aegean Sea basins.

Climate and Hydrology

The sea's surface circulation is governed by the two-layer flow through the Bosphorus Strait and the Dardanelles influenced by the Black Sea outflow and the Aegean Sea inflow. Seasonal variation is affected by the Marmara Region climate, Mediterranean cyclones tracked by institutions such as Turkish State Meteorological Service, and large-scale patterns like the North Atlantic Oscillation. Salinity gradients, thermohaline structures, and stratification lead to anoxic conditions in bottom waters similar to those documented in the Black Sea. Meteorological influences from Istanbul and the Bosphorus corridor drive wind regimes that affect wave climate and storm surge recorded by coastal ports such as Çanakkale Harbour, Istanbul Port, and Bandırma Port.

Ecology and Biodiversity

The sea supports habitats ranging from coastal lagoons and estuaries near Sakarya deltas to rocky reefs around islands like Marmara Island and seagrass beds documented near Gulf of Erdek. Key species include commercially exploited fishes such as European anchovy, bluefish, tuna, and various mullet species, as well as invertebrates like European lobster and Mediterranean mussel. Marine mammals recorded historically and occasionally sighted include common bottlenose dolphin, striped dolphin, and episodic reports of Harbour porpoise. Coastal wetlands provide habitat for bird species associated with Sakarya Delta and migration corridors used by birds recorded at Lake Büyükçekmece and other wetland sites. Biological communities are influenced by invasive species and introductions linked to shipping lanes connecting Black Sea and Aegean Sea ports such as Istanbul, Izmir, Samsun, and Constanța.

History and Human Use

The sea has been central to civilizations including the Byzantine Empire, the Ottoman Empire, and classical Greek city-states such as Miletus and Chalcis that used maritime routes linking Thrace and Ionia. Naval engagements and passages include movements in campaigns like the Gallipoli Campaign and earlier Byzantine–Ottoman Wars maritime logistics. Coastal fortifications include Rumeli Fortress and Anadolu Fortress guarding the Bosphorus Strait approaches, while straits control was pivotal in treaties such as the Treaty of Lausanne and diplomatic negotiations involving Allied Powers and Ottoman Empire successors. Archaeological sites on islands and peninsulas reveal Bronze Age, Classical, Roman, and Ottoman remains; underwater archaeology has recorded shipwrecks tied to trade routes connecting Venice, Genoa, Pisa, Constantinople, and Levantine ports.

Economy and Transport

Maritime transport connects major hubs including Istanbul, Çanakkale, Bandırma, Tekirdağ, and Yalova with ferry, cargo, and Ro-Ro services operated by companies and authorities such as İDO, Türk Loydu, and Turkish State Railways-linked ferries. Fishing and aquaculture involve fleets registered in ports like Erdek and facilities in Marmara Region provinces. Offshore and coastal industries cluster around shipyards in Yalova, Istanbul Tuzla Shipyards, and maritime logistics nodes linked to railheads toward Ankara and Edirne. Major infrastructure includes the Marmaray rail tunnel under the Bosphorus Strait and the Yavuz Sultan Selim Bridge corridor that influence traffic patterns, while pipelines and energy corridors run through adjacent regions connecting to projects involving Gazprom and regional suppliers.

Environmental Issues and Conservation

Environmental pressures include eutrophication, hypoxia in deep basins, pollution from urban wastewater from Istanbul and industrial effluents from Kocaeli, invasive species via ballast water from ships linking Black Sea and Aegean Sea routes, and impacts from events like the 1999 İzmit earthquake that altered coastal zones. Conservation actions involve Turkish agencies and NGOs, protected area designations near wetlands like Lake Manyas Nature Park and transboundary programs with organizations such as UNESCO for cultural heritage at Çanakkale, scientific monitoring by institutions including Istanbul Technical University and Middle East Technical University, and restoration projects addressing seagrasses and fishery management consistent with directives promoted by international bodies like the European Union for environmental standards.

Category:Seas of Turkey