Temporal variations of nutrients, chlorophyll a and particulate matter in three coastal lagoons of Amvrakikos Gulf (Ionian sea, Greece)

The temporal variations of nutrients, chlorophyll a (chi a), suspended part iculate matter (SPM) and particulate organic carbon (POC) were measured ove r 12 months in three shallow coastal brackish water lagoons of the Amvrakik os Gulf, Ionian Sea. Two of the lagoons, Tsoukalio and Rodia, are interconn ected but separated from Logarou by a narrow strip of land. Logarou has a b etter water exchange with the sea as indicated by the higher salinity and d issolved oxygen concentrations and the smaller variation of the above-menti oned parameters. Nitrate concentrations were largely the same in the three lagoons and higher than in the Amvrakikos Gulf. Phosphate concentrations in Logarou exceeded by far those of Tsoukalio/Rodia; the increased phosphate levels recorded in January caused an extended phytoplankton bloom with chi a concentrations higher than in the other two lagoons. Chi a in Tsoukalio w as positively correlated with nitrate whereas in the most shallow lagoon, L ogarou, it showed a positive correlation with light winds (force 4 and lowe r), probably caused by resuspension from the sediment. Increased phytoplank ton biomass in Logarou coupled with the better water exchange may be relate d to the higher fish production in this lagoon.