CS08 Biogeochemical Cycles
Date: Monday, June 10, 2002
Time: 10:45:00 AM
Location: Saanich
 
SchauserI, Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany, schauser@igb-berlin.de
Hupfer, M, , IGB, Berlin, Germany, hupfer@igb-berlin.de
Brüggemann, R, , IGB, Berlin, Germany, brg@igb-berlin.de
 
A PHOSPHORUS DIAGENETIC MODEL TO CALCULATE EFFECTS OF IN-LAKE MEASURES ON THE PHOSPHORUS RETENTION
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The internal phosphorus (P) cycle can delay the effects of external P load reduction. In-lake measures are used to speed up the recovery process or to substitute external measures. Some of them aim at influencing the P retention in the sediment. Mechanistic models are used to understand the complex interactions of diagenetic processes. A P-diagenetic model (SPIEL) has been developed for eutrophic lake sediments to predict the development of P release after an in-lake measure has been carried out. It is structured in modules. The main module calculates the P cycle within the sediment. Other modules can be added: a submodule to calculate the aerobic layer thickness, a submodule for the iron-sulphur cycle, a submodule for the Al-sorption capacity and a submodule for the change in porosity. Thus, it is possible to create measure specific models by combining different modules, e.g. for oxidation with oxygen or nitrate, precipitation with iron or aluminium, capping, hypolimnetic withdrawal and measure combinations. It has been calibrated for Lake Sempach, Switzerland, and different scenarios have been calculated.