Temporal Variation of Organic and Inorganic Carbon Transport from the Southeastern Black Sea (Trabzon Province) Rivers

Abstract

The input of organic carbon being an indicator of organic pollution as well to the oceans provides crucial sources in food web of estuarine ecosystems. The Black Sea surrounded by six countries is the world’s largest land-locked inland sea and its total length of the coastal zone is 4,340 km, of which 1,400 km is shared by Turkey. The Black Sea receives annually a considerable freshwater input from the rivers carrying substantial loads of organic matter, nutrients and anthropogenic pollutants and the coastal parts are highly affected by eutrophication. The aim of this study is to determine the temporal variability of total carbon (TC), total organic carbon (TOC) and total inorganic carbon (TIC) carried from the eight Turkish streams to the Black Sea. The streams included in this study are Ağasar, Fol, Galanima, Değirmendere, Yomra, Karadere, Manahoz and Solaklı, within the boundaries of Trabzon Province, the most densely populated city located in the coast of Southeastern Black Sea. The water sampling studies have been monthly conducted in one station, which was selected at the point where the stream is discharged into the Black Sea, for each stream during a period of twelve months between March 2015 and February 2016. Considering the mean values for each stream, TOC concentration fluctuated from 1.59 to 25.90 mg/L and the Stream Yomra being under immense pressure due to various kinds of anthropogenic activities among which sand and gravel mining is the most disastrous one was the most critical one. The streams showed high TC and TIC yields during the summer and autumn months, corresponding to the seasonal trend of stream discharge. It was also found that TIC comprised the majority of the total carbon concentration, with mean percentages ranging from 68.9% to 84.06% in all of the streams.