Assessing P status and trophic level of two lakes by speciation of particulate phosphorus forms

Seasonal variability of dissolved and particulate P forms was investigated in two lakes in Mecklenburg-Western Pomerania (North-East Germany): the polymictic Lake Bützow and the dimictic Lake Dudinghausen. Both lakes had a different trophic status according to the classic parameter total phosphorus, chlorophyll-a as well as phytoplankton biomass and composition. The aim of the study was to test P compounds and P fractions for characterization of the nutrient status of the phytoplankton, especially Polyphosphates and Phospholipids. The field study shows, that these intracellular reserve compounds in algae can not reflect the different nutrient status of the phytoplankton in the two lakes and is therefore not a more sensitive scale to indicate phosphorus limitation of plankton communities.