BaselineEvaluation of spatial and temporal variations of inorganic nutrient species in the eastern Aegean Sea waters

In this study, the state of the five stations' quality was assessed on the basis of determination of temporal and spatial variability of nutrients with physicochemical variables. Besides this, organic matter of sediment, secchi disc depth and suspended solids were also determined. The samples were collected seasonally from different areas such as harbor and important touristic marinas along the eastern Aegean during June 2008-2009. As a result, the nutrients ranged between NH4: 0.10-25.6, NO2: 0.01-1.5, NO3: 0.19-7.0, o.PO4: 0.17-6.8, TPO4: 0.32-9.6 and Si: 0.30-13.8 μM, respectively. Precipitation leads to large changes in temperature, salinity, dissolved oxygen and nutrients. The highest nutrient values in this study were observed during the rainy season except o.PO4-P and TPO4-P. However, the physico-chemical variables have exhibited considerable temporal variations while nutrients showed spatial differences. The relatively high nutrient increase in the sampling stations coupled with surface runoff events during rainy period and pollution arising from both point and non-point sources.

► Temporal and spatial variations of nutrients were evaluated in the eastern Aegean. ► Physicochemical variables and organic matter were measured in the sampling area. ► Temporal variations were generally observed for physicochemical parameters. ► Total and orthophosphate showed significant variation among stations. ► Higher nutrient levels were generally recorded in the inner part of Izmir Bay.