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Aquatic Microbial Ecology

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AME 26:73-80 (2001)  -  doi:10.3354/ame026073

Decomposition of alder leaves in two heavy metal-polluted streams in central Germany

K. R. Sridhar*, Gudrun Krauss, Felix Bärlocher**, N. S. Raviraja*, Rainer Wennrich***, Renate Baumbach****, Gerd-Joachim Krauss****

Microbiology of Subterrestrial Aquatic Systems Group, UFZ Centre for Environmental Research Leipzig-Halle, 06120 Halle, Germany
Present addresses: *Department of Biosciences, Mangalore University, Mangalgangotri, 574 199 Mangalore, Karnataka, India **Corresponding author. Department of Biology, Mount Allison University, 63B York Street, Sackville, New Brunswick E4L 1G7, Canada. E-mail: ***Department of Analytical Chemistry, UFZ Centre for Environmental Research Leipzig/Halle, 04318 Leipzig, Germany ****Department of Biochemistry/Biotechnology, Division of Ecology and Plant Biochemistry, Martin-Luther-Universität, 06099 Halle, Germany

ABSTRACT: In the former copper shale mining district of Mansfeld, central Germany, weathering of slag heaps and dumps resulted in groundwater, lakes and streams with extremely high heavy metal and metalloid concentrations (Zn up to 2.6 g l-1; Cu, Pb, Cs, Cd, As up to 13 mg l-1). We followed decomposition of Alnus glutinosa leaves in 2 streams, one with a high (H4) and one with a moderate (H9) load of these metals. In H9, mass loss closely followed an exponential decay curve (k = 0.055 d-1); in H4, leaf mass remained constant after a very rapid initial decay (k = 0.12) during the first 4 wk. Fungal biomass, estimated by ergosterol measurements, reached values of up to 1.1% (H9) or 0.36% (H4) of total detrital mass, corresponding to 6 and 2%, respectively, of maxima reported from nonpolluted streams. Conidium production by aquatic hyphomycetes was reduced to 10% (H9) and 0.01% (H4) of highest literature values. After 4 wk of stream exposure, leaves had greatly increased levels of As, Cu, Fe, Mn (both streams), Pb and Zn (H4). Gammarus fossarum preferred leaves that had been conditioned in the stream for 2 (H9) or 4 (H4) wk over unconditioned leaves.

KEY WORDS: Aquatic hyphomycetes · Leaf conditioning · Pollution · Fungal biomass · Fungal reproduction · Conidia

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