Chapter The pressures and the ecological quality status of the Marmara Sea (Turkey) by using marine macroalgae and angiosperms

In the present study, the Marine Floristic Ecological Index (MARFEI) was tested to assess the impacts by using marine benthic macrophytes and pressures by using the Macroalgae-Land Uses Simplified Index (MA-LUSI) in the Marmara Sea (Turkey). Sampling of benthic macrophytes was made from 0-5 m depth at 29 different sites during the summer periods of 2017, 2018 and 2019. The study revealed good ecological status class (ESC) for 6 sites, moderate for 11 sites, poor for 8 sites and bad for 4 sites. MARFEIeqr showed a negative linear relationship with the pressure index MA-LUSI

Nutrient and organic carbon budgets in the sea of Marmara: A progressive effort on the biogeochemical cycles of carbon, nitrogen and phosphorus

Ph.D. - Doctoral Progra

Quantitative comparison of the influxes of nutrients and organic carbon into the sea of marmara both from anthropogenic sources and from The Black Sea

The Sea of Marmara, an intercontinental basin with two narrow and shallow straits permitting the exchange of the Mediterranean and Black Sea waters, receives 2.8x10(4) tons TP (total phosphorus), 2.7x10(5) tons TN (total nitrogen) and 1.9x10(6) 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 Hem, 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

NUTRIENT AND ORGANIC CARBON EXCHANGES BETWEEN THE BLACK AND MARMARA SEAS THROUGH THE BOSPORUS STRAIT

ecent systematic chemical data, together with a new estimate of the water fluxes, permit the calculation of the total phosphorus (TP), nitrogen (TN) and organic carbon (TOC) exchanged between the Black and the Marmara Seas through the Bosphorus. Assuming the chemical concentrations of the exchanging waters to be constant on a yearly time scale, the estimated total annual fluxes are as follows

Elemental composition of seston and nutrient dynamics in the Sea of Marmara

The Sea of Marmara, an intercontinental basin with shallow and narrow straits, connects the Black and Mediterranean Seas. Data obtained during 1991-1996 have permitted the determination of the elemental composition of seston in the euphotic zone and the N:P ratio of the subhalocline waters of the Marmara Sea. Since primary production is always limited to the less saline upper layer (15-20 m), of the Marmara Sea, the subhalocline waters of Mediteranean origin are always rich in nutrients (NO3 + NO2 = 8-10 mu m, PO4 = 0.8-1.2 mu m) but depleted in dissolved oxygen (30-50 mu m) throughout the basin, yielding an -O-2:N:P ratio of 178.9:1. Pollution of the surface waters since the 60s has modified the subhalocline nutrient chemistry slightly. In the euphotic zone, the N:P ratio of the seston changes from 5.9 to 9.5 between the less and more productive periods. Though the biology of the Marmara has changed significantly during the previous two decades, the close relationship observed between the elemental composition of the surface seston and the NO3:PO4 ratio of the subhalocline waters strongly suggests that during the whole year primary production throughout the basin and POM export to the lower layer remain nitrogen-limited. This suggestion needs to be confirmed by bio-assays, biological studies and sediment trap data from the upper subhalocline depths. Nonetheless, the counterflows in the Marmara basin possess relatively low N:P ratios in both dissolved and particulate nutrients and extend as far as the adjacent sea