Paleolimnologiczna interpretacja krzemionki biogenicznej - dyskusja na przykładzie wybranych jezior Niżu Polskiego

The paper outlines some problems in the interpretation of biogenic silica content in lacustrine sediments in the context of reconstruction of past changes in lake ecosystems throughout the Holocene. The discussion is centered on four lakes located on the Polish Lowland (Lake Sarbsko, Lake Ostrowite, Lake Skrzynka and Lake Gąsak), which display different lithology and chemical composition of bottom deposits. From the data collected it emerges that SiO2biog cannot be regarded as an unambiguous indicator of lake trophic state. Instead, paleolimnological interpretations of biogenic silica should include dilution by carbonates, SiO2ter and/or organic matter, H4SiO4-limited diatom productivity and lake water dynamics. The understanding of SiO2biog benefits from supplementation with other geochemical and paleoecological proxies