RESPONSES OF PHYTOPLANKTON AND ZOOPLANKTON TO LIMING IN A SMALL ACIDIFIED HUMIC LAKE

Liming resulted in an immediate and transitory decrease of plankton bi omass and phytoplankton primary production in the limed part of an aci dified humic lake. In the longer term liming has changed species compo sition and dominance of phyto- and zooplankton Due to increased transp arency and improved oxygen conditions plankton biomass peaked deeper i n the water column after liming. During the three years post-liming pe riod phyto- and zooplankton communities have changed less than reporte d in several other studies. This is largely because liming was carried out well before the collapse of perch population, which has controlle d zooplankton both in the pre- and post-treatment period.