scholarly journals Water Exchange through Canal İstanbul and Bosphorus Strait

2017 ◽  
Vol 18 (1) ◽  
pp. 77 ◽  
Author(s):  
A. SÖZER ◽  
E. ÖZSOY

The Turkish Straits System (TSS) regulates the transports of water, material and energy between the Black Sea and the Mediterranean Sea. Amidst existing environmental threats to the region surrounding İstanbul, the environmental footprint of the proposed Canal İstanbul project needs to be evaluated through methods of natural science. We take the elementary step to answer the particular problem of coupled strait dynamics by adding the Canal to an existing hydrodynamic model and estimate changes in their common response. Compared to the virtually unmodified exchange flow in the Bosphorus, the flow in the Canal has a weak lower layer current component, contrasted with intense currents at the exit controls at its junction with the Marmara Sea. The net flux through this simplest hypothetical TSS configuration is considerably increased for a given sea level difference across the system. The modified regime is expected to have climatological consequences.

1995 ◽  
Vol 32 (2) ◽  
pp. 115-121 ◽  
Author(s):  
Suleyman Tugrul ◽  
Colpan Polat

The Sea of Marmara, an intercontinental basin with two narrow and shallow straits permitting the exchange of the Mediterranean and Black Sea waters, receives 2.8×104 tons TP (total phosphorus), 2.7×105 tons TN (total nitrogen) and 1.9×106 tons TOC (total organic carbon) per year from the Black Sea inflow, from the lower layer by vertical mixing and from anthropogenic inputs of various origins including riverine discharges. The Black Sea input through the Bosphorus constitutes about 35, 64 and 77 %, respectively, of the total annual loads of TP, TN and TOC entering the Marmara surface waters. Pollution loadings from Istanbul make up a major fraction (40-65%) of the total anthropogenic discharges. The biochemical properties of the productive Marmara upper layer appear to be dominated by the inputs both from its lower layer by vertical mixing and from the Black Sea throughout the year. Pollution discharges from Istanbul have secondary importance for the nutrient and organic carbon pools of the Marmara Sea; however, the land-based chemical pollution has drastically modified the ecosystem of coastal margins and semi-enclosed bays (e.g. Golden Horn, Izmit and Gemlik) where water exchanges with the open sea are limited. Biologically labile nutrients increasingly exported from the Black Sea in the spring-early summer, are compensated by importation from the Marmara Sea through the Bosphorus underflow. The less labile dissolved organic nitrogen and carbon input from the Black Sea appears to reach as far as the Aegean basin of the Northeastern Mediterranean in 4-5 months without contributing to the net production in the Marmara Sea.


2015 ◽  
Vol 16 (2) ◽  
pp. 444 ◽  
Author(s):  
V. MADERICH ◽  
Y. ILYIN ◽  
E. LEMESHKO

A chain of simple linked models is used to simulate the seasonal and interannual variability of the Turkish Straits System. This chain includes two-layer hydraulic models of the Bosphorus and Dardanelles straits simulating the exchange in terms of level and density difference along each strait, and a one-dimensional area averaged layered model of the Marmara Sea. The chain of models is complemented also by the similar layered model of the Black Sea proper and by a one-layer Azov Sea model with the Kerch Strait. This linked chain of models is used to study the seasonal and interannual variability of the system in the period 1970-2009. The salinity of the Black Sea water flowing into the Aegean Sea increases by approximately 1.7 times through entrainment from the lower layer. The flow entering into the lower layer of the Dardanelles Strait from the Aegean Sea is reduced by nearly 80% when it reaches the Black Sea. In the seasonal scale, a maximal transport in the upper layer and minimal transport in the bottom layer are during winter/spring for the Bosphorus and in spring for the Dardanelles Strait, whereas minimal transport in upper layer and maximal undercurrent are during the summer for the Bosphorus Strait and autumn for the Dardanelles Strait. The increase of freshwater flux into the Black Sea in interannual time scales (41 m3s-1 per year) is accompanied by a more than twofold growth of the Dardanelles outflow to the North Aegean (102 m3s-1 per year).


2002 ◽  
Vol 3 (1) ◽  
pp. 33 ◽  
Author(s):  
S. TUGRUL ◽  
T. BESIKTEPE ◽  
I. SALIHOGLU

Long-term data obtained in the Turkish Strait System (TSS) including the Sea of Marmara, the Dardanelles and Bosphorus straits, during 1990-2000, have permitted us to calculate seasonal and annual fluxes of water and nutrients (nitrate, phosphate) exchanged between the Aegean and Black Seas through the TSS. Two-layer flow regimes in the TSS introduce the brackish waters of the Black Sea into the Aegean basin of the northeastern Mediterranean throughout the year. A counter flow in the TSS carries the salty Mediterranean water into the Black Sea via the Marmara deep basin. The annual volume influx from the Black Sea to the Marmara upper layer is nearly two-fold the salty water exported from the Marmara to the Black Sea via the Bosphorus underflow. The brackish Black Sea inflow is relatively rich in nitrate and phosphate in winter, decreasing to the lowest levels in late summer and autumn. Biologically labile nutrients of Black Sea origin are utilized in photosynthetic processes in the Marmara Sea and are partly exported to the Marmara lower layer. Eventually, the brackish Black Sea waters reach the Dardanelles Strait, with modified bio-chemical properties. On the other hand, the salty Mediterranean waters with low concentrations of nutrients enter the Marmara deep basin. During threir 6-7 year sojourn in the Marmara basin, the salty waters become enriched in nitrate (DIN) and phosphate (DIP), due to oxidation of planktonic particles sinking from the Marmara surface layer. The annual nutrient inputs from the Black Sea to the Marmara basin were estimated as 8.17x108 moles of DIN and 4.25x107 moles of DIP, which are much less than the importation from the Marmara lower layer via the Bosphorus undercurrent. The salty Aegean water introduces nearly 6.13x108 moles of DIN and 2.79x107 moles of DIP into the Marmara lower layer. The estimated DIP outflux from the Aegean Sea is nearly 2 times less than the importation from the Marmara Sea via the Dardanelles Strait.


2019 ◽  
Author(s):  
Murat Gunduz ◽  
Emin Özsoy ◽  
Robinson Hordoir

Abstract. The Bosphorus exchange is of critical importance for hydrodynamics of the Black Sea. In this study, we report on the development of a medium resolution circulation model of the Black Sea, making use of up-to-date topography, atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange enabled by adding the Bosphorus Strait with an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing, convective water mass formation processes compared with observations. The present formulation with temperature and salinity relaxed to the observed seasonal climatology of the Marmara box and open boundary conditions are found to enable Bosphorus exchange with upper, lower layer and net fluxes comparable to the observed range. This in turn enables to capture the trend of rapid climatic change observed in the Black Sea in the last decade.


2020 ◽  
Vol 13 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Murat Gunduz ◽  
Emin Özsoy ◽  
Robinson Hordoir

Abstract. The Bosphorus exchange is of critical importance for hydrodynamics and hydroclimatology of the Black Sea. In this study, we report on the development of a medium-resolution circulation model of the Black Sea, making use of surface atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange, enabled by adding elementary details of strait and coastal topography and seasonal hydrology specified in an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing and convective water mass formation processes in the model, which are then compared with observations. Open boundary conditions relaxed to seasonal hydrology specified in the artificial box are found to enable Bosphorus exchange with a proper upper layer, lower layer and net fluxes comparable to the observed ranges. These improvements at the artificial boundary and in the interior evolution of the Black Sea allow the study to capture daily, seasonal to decadal climatic variability and change observed in the Black Sea in the last few decades.


1995 ◽  
Vol 32 (7) ◽  
pp. 63-70
Author(s):  
I. Ethem Gönenç ◽  
Oguz Müftüoglu ◽  
Bilsen Beler Baykal ◽  
Ertugrul Dogan ◽  
Hüseyin Yüce ◽  
...  

Unlike other seas of the world, the Black Sea shows unique quality and trophic properties. Fortunately, only the upper layer water of the Black Sea is introduced into the Bosphorus and has a significant effect on the quality and trophic conditions of the Marmara Sea. These effects are discussed in the light of data obtained from collaborative efforts of Turkish and Romanian research institutions and processed satellite images. In conjunction with these discussions, recommendations for a suitable effluent disposal strategy for Istanbul's wastewater have been given.


1995 ◽  
Vol 32 (2) ◽  
pp. 141-148 ◽  
Author(s):  
I. S. Hansen ◽  
H. J. Vested ◽  
M. A. Latif

A modelling study of the hydrodynamics and spreading of wastewater from existing and future outfalls in the Bosphorus region has been conducted applying a 3-Dimensional model. The modelling is based on SYSTEM 3, which is a general modelling system for baroclinic flow simulating unsteady currents, waterlevels, salinity and temperature within the model area. The model set-up covers the Black Sea-Bosphorus-Marmara Sea junction area. The set-up is calibrated by data from a dedicated field program and previous field experience. The model is designed to describe the characteristic features of the flow in the junction area such as the effects of variations in waterlevel differences between the Sea of Marmara and the Black Sea on the important two-layer structure in the strait and the flow fields generated by the upper layer jet in the Bosphorus-Marmara junction. This model has been applied for evaluation of disposal of wastewater and for the subsequent water quality studies. The general use of a baroclinic 3-D hydrodynamic model to simulate disposal of wastewater is discussed. Examples of the application of the model of the junction area to evaluate the different strategies for disposal of wastewater are presented.


2002 ◽  
Vol 46 (8) ◽  
pp. 59-66 ◽  
Author(s):  
E. Okuş ◽  
A. Aslan-Yilmaz ◽  
A. Yüksek ◽  
S. Taş ◽  
V. Tüfekçi

As part of a five years monitoring project “Water Quality Monitoring of the Strait of Istanbul”, February-December 1999 nutrient dynamics of the Black Sea-the Sea of Marmara transect are studied to evaluate the effect of discharges given by deep disposals. Through a one-year study, upper layer nutrient concentrations were generally under the effect of northwestern-shelf Black Sea originated waters. This effect was strictly observed in July, when the upper layer flow was the thickest. On the other hand, partly in November but especially in December the northwestern-shelf Black Sea originated water flow was a minimum resulting in similar concentrations in both layers. Nutrient fluctuations also affected the chlorophyll a and POC concentrations as parameters of productivity. The nutrient concentrations decreased with the effect of spring bloom and highest chlorophyll a values were detected in November at Strait stations that did not match to the Sea of Marmara values. This fact represents the time-scale difference between the Black Sea and the Sea of Marmara. On the contrary, high nutrient concentrations in the lower layer (especially inorganic phosphate), and therefore low N:P ratios reflect the effect of deep discharge. Vertical mixing caused by meteorological conditions of the shallow station (M3) under the effect of surface discharges resulted in homogenous distribution of nutrients. Nutrient concentrations of the stations affected by deep discharge showed that the two-layer stratification of the system did not permit the discharge mix to the upper layer.


2019 ◽  
Author(s):  
Anastasia G. Yanchilina ◽  
Celine Grall ◽  
William B. F. Ryan ◽  
Jerry F. McManus ◽  
Candace O. Major

Abstract. The Marine Isotope Stage 3 (MIS 3) is considered a period of persistent and rapid climate and sea level variabilities during which eustatic sea level is observed to have varied by tens of meters. Constraints on local sea level during this time are critical for further estimates of these variabilities. We here present constraints on relative sea level in the Marmara and Black Sea regions in the northeastern Mediterranean, inferred from reconstructions of the history of the connections and disconnections (partial or total) of these seas together with the global ocean. We use a set of independent data from seismic imaging and core-analyses to infer that the Marmara and Black Seas remained connected persistent freshwater lakes that outflowed to the global ocean during the majority of MIS 3. Marine water intrusion during the early MIS-3 stage may have occurred into the Marmara Sea-Lake but not the Black Sea-Lake. This suggests that the relative sea level was near the paleo-elevation of the Bosporus sill and possibly slightly above the Dardanelles paleo-elevation, ~80 mbsl. The Eustatic sea level may have been even lower, considering the isostatic effects of the Eurasian ice sheet would have locally uplifted the topography of the northeastern Mediterrranean.


2014 ◽  
Vol 5 (1) ◽  
pp. 49-53 ◽  
Author(s):  
A. Y. Varigin

The degree of phenotypic plasticity in the Idotea baltica basteri Audouin, 1827 (Crustacea, Isopoda) sex ratio of the fouling community in the Odessa bay of the Black Sea was determined. The ratio of males and females in three main phenotypes of I. baltica basteri, namely: uniformis, albafusca and lineata was found. Crustaceans were collected on the underwater surface of traverses, located in three sea districts with the different degrees of water exchange intensity with the open sea. Water depth at the wall of traverses ranged from 1 to2,5 m. In the first most opened district among the individuals of uniformis phenotype the ratio of males and females was equal to 1:4, that for albafusca – 1:1,3 and lineata – 1:1. In the second area with the release of drainage waters among the individuals of uniformis phenotype this ratio was equal to 1:4,5, while the albafusca and lineata figures were 1:1,5 and 1:1, accordingly. In the third region, with the most difficult water exchange, among the individuals of phenotypes the ratios of males and females were as follows: uniformis – 1:8, albafusca – 1:2, and lineata – 1:1. When moving from the opened to semi-enclosed area among the individuals of all phenotypes there was a gradual decline in the proportion of males and accordingly, increases of the proportion of females. The greatest number of males in all areas under study is observed among the individuals of lineata phenotype, and that of females – among the individuals of uniformis phenotype. It is found that monochromatic colored females prefer to stay in the shaded places among the seagrass beds and brightly colored males usually move actively along the outside of the substrata. 


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