Total alkaline phosphatase activity (ALP-EC 3.1.3.1) of water in the River Odra estuary (North-West Poland)

The Odra estuary includes, as its major part, the brackish Szczecin Lagoon. This consists of two parts: the Kleines Haff (located in Germany) and the Wielki Zalew located in Poland. The Lagoon receives the River Odra water supplied from the south; prior to being discharged into the Lagoon, part of the Odra flow passes through Lake Dąbie. In its northern part, the Lagoon connects – via three straits (the Peene, Świna and Dziwna) - with the Pomeranian Bay, a Baltic embayment. Water in the lakes of the River Odra estuary were the subjects of a five-year study (2008-2012). Total alkaline phosphatase activity was determined seven times a year in these environments. The zonal study demonstrated that the top sub littoral layer (1 m) featured the highest alkaline phosphatase activity among all the analyzed zones. A study of seasonal fluctuations showed that a maximum total alkaline phosphatase activity occurred in spring (May) and summer (July, August). Basing on this parameter, no increase in eutrophication process in the River Odra estuary was determined in the course of a 5-year study.