Seasonality of Algal Pigments in the Sea Water and Interstitial Water/Sediment System of an Eastern Mediterranean Coastal Area

An effort has been made herein to describe the seasonal variation of the microalgal pigments, nutrient concentrations and other physicochemical parameters in a sandy and eutrophic coastal area of North Euboikos gulf, Aegean Sea. The algal pigments chlorophyll a, chlorophyll b, chlorophyll c, fucoxanthin, zeaxanthin, peridinin, 19 -hexanoyloxyfucoxanthin, 19 -butanoyloxyfucoxanthin, pheophytin a and pheophytin b were analysed by High Performance Liquid Chromatography (HPLC) in the interstitial water/sediment system (IW) and sea water (SW) during 1999. Chl a was recorded in all samples and its annual mean values were 1709 mg m 3 in IW and 0·76 mg m 3 in SW. Fucoxanthin was the most abundant accessory pigment in both media giving a total average 1183 mg m 3 in IW and 0·49 mg m 3 in SW while the pheophytin a mean values were 1183 mg m 3 in IW and 0·49 mg m 3 in SW. The vertical distributions of various pigments in the three layers of IW (0–3 mm, 10–13 mm and 30–33 mm) fluctuated quantitatively on a monthly basis. Only in a few cases certain pigments (Chl a, Chl c, Fuco and HEX) were equally distributed in the three layers (Chl c: June–July, Fuco: January–December, HEX: March, Chl a: April–May–January), while the distribution between layers was unequal during the rest of the year. Special emphasis was given in the analysis of data derived from the top layer (0–3 mm) of interstitial water/sediment system (IW) and near bottom water (NBW) e.g. the interface of two media. The ratios of pigment/Chl a and correlations were also estimated in order to enlighten the relationships among various pigments spatially and temporally. By using stepwise forward multiple regression we determined the pigments (Fuco, HEX, Chl c and BUF) that are the significant contributors collectively to the total Chl a biomass and we revealed differences in pigment contributions among various layers of IW or depths in SW and between media.