Size-fractionated phytoplankton and nutrient dynamics in the inner part of İzmir Bay, eastern Aegean Sea

References (1)

1. 00 (max) Bizsel et al., 2001 0.04–65.67 0.00–7.59 0.01–5.46 0.09–12.06 0.00–6.38 Kaymakçı et al., 2001 80 (max) 12 (max) 60 (max) 00 (max) Gencay and Büyükışık, 2004 0.06–40.72 0.19–24.86 0.00–25.90 0.87–17.58 0.78–48.60 0.00–3.93/1.31 Kükrer and Aydın, 2006 0.00–40.94/5.31 0.00–21.35/3.28 0.00–28.99/2.27 0.00–31.41/3.28 0.16–54.12/10.82 0.00–66.13/4.26 Sunlu et al., 2012 0.23–22.28/3.28 54–11.7 7/4.27 0.00–3.51/0.64 0.00–5.96/2.17 99–41.94/10.80 03–30.26/12.44 This study Numbers written after “/” indicate average values. than NO – 3 -N over the sampling period. McCarty (1980) reported that this situation was normal and NO – 2 -N accumulates noticeably under low DO condition. Koray et al. (1992) emphasised that a large part of total nitrogen in the polluted İzmir Bay was ammonium from industrial and domestic wastes. In contrast, in our study nitrate had the largest share of total nitrogen concentration due to the WTP, which reduces ammonium inputs. Additionally, ammonium concentration is kept under control by phytoplankton over a year. In spite of this progress, the ammonium enrichment continues owing to the creeks and sediment, which have high ammonium concentrations (Ozkan et al., 2008). The capacity of the wastewater plant has not been sufficient for phosphate reduction according to previous studies (Kontas et al., 2004; Kucuksezgin et al., 2006; Kükrer & Aydın, 2006). Although the phosphate concentration we found was lower than the values in those studies, it is thought that the decreases in phosphate concentration are a result of phytoplankton consumption. The observed mean N:P value was lower than the assimilatory optimal (N:P = 15:1) in conformity with Redfield’s ratio N:P = 16:1 due to the reduction in nitrogen. The Eastern Mediterranean is one of the world’s poorest seas as a concept based on the impoverished phytoplankton biomass and productivity levels mainly due to phosphorus deficiency (Ignatiades et al., 2002). However, in İzmir Bay, as a part of the Mediterranean basin, nitrogen is a limited nutrient. Nutrient levels found in this study in the inner bay were higher than those in the other parts of the Aegean Sea (Table 6). Nutrients and light are probably more available to phytoplankton because of the smaller volume and the shallowness of the water column (Thomas et al., 2005). These structures of ST 1, ST 2, and ST 3 stimulate the increase in the phytoplankton biomass. The nanoplankton dominated the phytoplankton chlorophyll-a biomass