Daily variations in stratification in İzmit Bay

We studied the diurnal variation of stratification in İzmit Bay with temperature and current velocity, and investigated the influence of atmospheric conditions. In the east of the bay entrance, 10-min temperature and hourly current measurements were made between the dates of 4 February 2015 and 24 April 2015, down to about 40 m depth in the water column. In addition to this, hourly temperature and salinity with depth data were collected between the dates of 4 and 7 February 2015 by a research vessel. The meteorological parameters for the atmospheric conditions were obtained from the closest weather stations Yalova, Çınarcık, and Gebze . Thermocline depth varied between 20 and 30 m with instant changes at 6 to 35 m of depth due to strong wind conditions with 3 days of time delay. The south-westerly current directions were found in both layers, but the current speed decayed with depth. The high buoyancy frequency due to strong stratification decreased in strong wind and shear dominated the mixing process. Air pressure, air temperature, north-south component of wind and sea level had a semidiurnal cycle. A high-frequency measurement in a 2-layer system is highly significant to understand, explain, and determine the cause and effect relationships of hydrographic processes.

Keywords:

İzmit Bay, stratification, temperature-chain data, time series diurnal changes, wind induced mixing, Richardson number,

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Algan O, Altıok H, Yüce H (1999). Seasonal Variation of Suspended Particulate Matter in Two-layered İzmit Bay, Turkey.
Estuarine, Coastal and Shelf Science 49: 235-250. doi: 10.1006/ ecss.1999.0494
Altıok H, Legovich T, Kurter A (1996). A Case Study of Circulation and Mixing Processes in Two-layered Water System: İzmit Bay. In: Physics of Estuaries and Coastal Seas, 8th International Biennial Conference, Sponsored by The Netherlands Centre for Coastal Research; The Hague, Netherland (8-12 September). pp. 92-95.
Balkıs N (2003). The effect of Marmara (İzmit) earthquake on the chemical oceanography of İzmit Bay, Turkey. Marine Pollution Bulletin 46:865-878.
Baştürk O, Tuğrul S, Sunay M, Balkaş T, Morkoç E et al. (1985). Determination of oceanographic characteristics and assimilation capacity of İzmit Bay. NATO TU-WATERS Project, May 1984–May 1985 period. Gebze, Turkey: TÜBİTAK-MAM Publication.
Beşiktepe ŞT, Sur HI, Özsoy E, Latif MA, Oğuz T et al. (1994). The circulation and hydrography of the Marmara Sea. Progress in Oceanography 34(4): 285-333.
Ergül HA, Aksan S, İpşiroğlu M (2018). Assessment of the consecutive harmful dinoflagellate blooms during 2015 in the İzmit Bay (the Marmara Sea). Acta Oceanologica Sinica 37: 91- 101. doi: 10.1007/s13131-018-1191-7
Karakoç FT, Tolun L, Henkelmann B, Klimm C, Okay O et al. (2002). Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in the bay of Marmara Sea: İzmit Bay. Environmental Pollution 119: 383-397.
Morkoç E, Legoviç T, Okay O, Tüfekçi H, Tüfekçi V et al. (2007). Changes of oceanographic characteristics and the state of pollution in the İzmit Bay following the earthquake of 1999. Environmental Geology 53: 103-112. doi: 10.1007/s00254-006- 0622-5
Müftüoğlu, AE (2008). Marmara Denizi Haliç ve Körfezleri’nin Hidrodinamik Yapısı. PhD, İstanbul University-IMSM, İstanbul, Turkey (in Turkish with an abstract in English).
Okay O, Tolun GL, Telli-Karakoç F, Tüfekçi V, Tüfekçi H et al. (2001). İzmit Bay ecosystem after Marmara earthquake and subsequent fire: the long-term data. Marine Pollution Bulletin 42:361-369. doi: 10.1016/S0025-326X(00)00163-6
Sur H (1988). Numerical Modelling Studies of Two-layer Flows in the Dardanelles Strait and the Bay of İzmit. PhD, METU-IMS, Erdemli, İçel, Turkey.
Turner JS (1973). Buoyancy Effects in Fluids. Cambridge, UK: Cambridge University Press.
Tolun GL, Ergenekon S, Murat Hocaoğlu S, Süha Dönertaş A, Çokacar T et al. (2012). Socioeconomic response to water quality: a first experience in science and policy integration for the İzmit Bay coastal system. Ecology and Society 17(3): 40. doi: 10.5751/ES-04984-170340
Tuğrul S, Sunay M, Başturk Ö, Balkaş TI (1986). The İzmit Bay case study. In: Kullenberg G (editor). The Role of Oceans as a Waste 498 Disposal Option. Dordrecht, Holand: Reidel, pp. 243-275.
Tüfekçi V, Balkıs N, Polat-Beken Ç, Ediger D, Mantıkçı M (2010). Phytoplankton composition and environmental conditions of a mucilage event in the Sea of Marmara. Turkish Journal of Biology 34: 199-210.
Ünlüata Ü, Oğuz T, Latif M, Özsoy E (1990). On the physical oceanography of the Turkish Straits, In: Pratt LJ (editor). The Physical Oceanography of Sea Straits. Kluwer Academic Publishers, pp. 25-60.