Detection of substrate influenced phosphorus emissions potentials in fens at re-wettings in the near future

For decades huge areas of fens in north-eastern Germany were drained for agriculture. Their re-wetting ist economically and politically forced and has been supported f.e.by Kyoto and EU Water Framework Directive. Rehabilitation has been introduced: lots of degraded fens are already re-wetted or are planed to be re-wetted in the near future. Re-wetting prevents peat humification by oxidation (emission of CO2) and returns the fens to their natural conditions. Re-wetting of degraded fens is often accompanied by negative side-effects. Changes in redox potentials and a strengthened emission of phosphorus are observered. The possibiliy of a supplementary immission of nutrients into adjacent water ecosystems has to taken into a special account, when managing degraded fens. The tractionation of peat-phosphorus provides additional information about potential mobility of P under different environmental conditions. Thus, the determination of phosphorus binding forms in peat substrates will help to understand the mechnisms of P-emission in fens after rewetting and leads to an estimation of P-emission potentials before a fen will be re-wetted. The objective of this research is to investigate, to what extend the P-binding forms and their emission potentials are influenced by the substrate and the degree of peat decomposion.