Extremely acidic mine lake ecosystems in Lusatia (Germany): characterization and development of sustainable, biology-based acidity removal technology

Abstract

The extremely acidic mining lakes of Lusatia (north-eastern Germany) were formed by the infilling of open-cast lignite pits following mine closure. These lakes typically have pH values of 2.4 to 3.4 and high concentrations of dissolved iron (and occasionally other metals) and sulphate. There is considerable political and socio-economic pressure to neutralise the lakes and develop their considerable recreational potential. In a multidisciplinary project funded by the BMBF (Bundesministerium für Bildung und Forschung) and LMBV (Lausitzer und Mitteldeutsche Bergbau- Verwaltungsgesellschaft mbH), the living conditions of these lakes have been documented and methodology is being developed to use controlled eutrophication (increased nutrient supply) to increase lake productivity and sustainably remove acidity through sediment bound and water column biologically-mediated processes. The merits of such an approach are discussed in relation to other approaches such as infilling with river water. This multidisciplinary project involves scientists from various universities and institutes in a coordinated approach.