SS3.10 Ecological Implications of Terrestrial Inputs into Lakes and Ponds
Date: Tuesday, June 11, 2002
Time: 4:30:00 PM
Location: Esquimalt
 
selig, uwe, university of rostock, institute of aquatic ecology, rostock, , uwe.selig@biologie.uni-rostock.de
Leipe, T, , baltic sea research insitute, rostock, , thomas.leipe@io-warnemuende.de
Dörfler, W, , university of kiel, kiel, , wdoerfler@ufg.uni-kiel.de
 
PHOSPHORUS PROFILES IN DEEP SEDIMENT CORES: THE IMPACT OF HUMAN SETTLEMENT ON PHOSPHORUS ACCUMULATION
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Sediment profiles (10 and 15 m long) from three dimictic postglacial lakes in Mecklenburg-Western Pommerania (North Germany), representing approximately the last 8000 to 13000 years, were investigated. In addition to the total nutrient concentration, P-binding was analyzed by chemical extraction; Scanning Electron Microscopy (SEM) and X-ray mirco-analyses were also conducted. The highest phosphorus concentrations were not determineted in the upper sediment or in pre-industrial phase. Rather, they were recorded in permanently anoxic sediments and extracted by bicarbonate-dithionite and NaOH; a high correlation to the redox-sensitive elements iron and manganese was found. SEM and X-ray mirco-analysis confirm the presence of Fe-Mn-P minerals. Based on palynological analysis, the development of human settlements in the catchment area of the lakes is described. Human activity - agriculture as well as amelioration - influenced the phosphorus accumulation and phosphorus binding in lake sediments. Generally, the chemical extraction method can be used to investigate deep sediment cores, but the interpretation of redox-sensitve and bioavailable fractions must be discussed and separatly considered by comparision to the surface sediment.