Nutrient inputs from two major rivers into the cilician basin of the north-eastern Mediterranean Sea

Abstract

Abstract In this study, dissolved nutrients concentrations were measured monthly at downstream points of the two regional rivers (the Berdan and Göksu rivers) flowing into the Cilician Basin of the North-eastern (NE) Mediterranean Sea. The dissolved nutrients data obtained between September 2021 and August 2022 were used to determine riverine nutrient fluxes. This study showed that spatial and temporal variations were recorded in nutrients concentrations of the two regional rivers with the maximum values consistently recorded in the Berdan River having lower volume fluxes. The annual nutrient inputs of the two regional rivers indicated that higher amounts of dissolved nutrients were carried by the Göksu River due to its higher volume flux rate. The calculated molar ratios from total nitrogen (TN) and phosphorus (TP) fluxes ranged from 13 in the Göksu River to 22 in the Berdan River. The higher TN/TP molar ratio compared to the classic Redfield Ratio of N/P in the Berdan River is very likely to modify nutrient dynamics leading to further eutrophication in the shelf waters of the NE Mediterranean Sea.