Palaeolimnological analyses as information source for large lake biomonitoring

Abstract

A routinely applicable palaeolimnological sampling and analysis programme for large lake monitoring was developed as part of the Lake Saimaa Biomonitoring Project (1990Project ( -1993. The scope of palaeolimnological analyses is to gain background information of the recent past (ca. 0-200 yr) of the lake ecosystem that is being monitored. We analyzed short sediment cores from three contrasting basins of the complex lake Saimaa in eastern Finland (nutrient-poor clearwater Lake Puruvesi; oligotrophic mesohumic Lake Paasivesi, and eutrophied and polluted mesohumic Lake Haukivesi). Each basin shows a unique developmental history under the various forms of human influence on the ecosystem. The following research approaches are evaluated in the study: echosounding, dating (210~b, varves, soot stratigraphy), element stratigraphies, biological remains (diatoms, cladocera, chironomids, sedimentary pigments).