Nutrient dynamics between sediment and overlying water in the inner part of Izmir Bay, Eastern Aegean

Abstract

The nutrient flux experiments for the sediments of Inner Izmir Bay were performed for the first time during January 2004-August 2004. The flux rates ranged between -127.9 and 358.2 microg atN m(-2) day(-1) for NH(4) (+), -47.88 and 320.9 microg at N m(-2) day(-1) for NO(2) (-), -62.96 and 121.3 microg at N m(-2) day(-1) for NO(3) (-), -64.1 and 528 microg atP m(-2) day(-1) for reactive phosphate (RP) and between -168.44 and 284.19 microg at Si m(-2) day(-1) for reactive silicate (RSi). Negative values were obtained from core incubations in winter except for nitrite (flux from water to sediment). The positive flux in all the core incubations during spring and summer (except nitrite in August) at least revealed that the sediment might be partially anoxic and/or included H(2)S. The turnover times obtained from water column nutrient inventory and flux rates indicated that Si and NH(4) (+) possessed a rapid cycle in water column. It was argued that NO(3) (-) would be more influenced by the removal processes within the sediment, therefore the water column would provide an additional contribution to the N limitation and the short turnover time of RP could rapidly supply RP to the water column. The continuous increase of pore water nutrient concentrations from January to August does not explain whether this nutrient reserve attains the next year with higher background levels or it is released back to environment at the end of autumn.