High Heterotrophic Bacterial Production in Acidic, Iron-Rich Mining Lakes

• N. Kamjunke ^[1] ; J. Tittel ^{[1] [4]} ; H. Krumbeck ^{[2] [5]} ; C. Beulker ^[2] ; J. Poerschmann ^[3]
  1. [1] University of Potsdam

     University of Potsdam

     Kreisfreie Stadt Potsdam, Alemania

     
  2. [2] Chair of Water Conservation, Research Station Bad Saarow, Brandenburg University of Technology at Cottbus, Bad Saarow, Germany
  3. [3] Department of Environmental Technology, Centre for Environmental Research Leipzig-Halle GmbH (UFZ), Germany
  4. [4] Department of Lake Research, UFZ-Centre for Environmental Research Leipzig-Halle, Magdeburg, Germany
  5. [5] Thetis IBN GmbH, Inst. F. biomolekulare Naturforschumg, Hamburg, Germany

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• Localización: Microbial ecology, ISSN-e 1432-184X, ISSN 0095-3628, Vol. 49, Nº. 3, 2005, págs. 425-433
• Idioma: inglés
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• Resumen

  • The acidic mining lakes of Eastern Germany are characterized by their extremely low pH and high iron concentrations. Low concentrations of CO2 in the epilimnion due to the low pH and reduced light transmission due to dissolved ferric iron potentially limit phytoplankton primary production (PP), whereas dissolved organic carbon (DOC) may promote heterotrophic production of bacteria (HP). We, therefore, tested whether HP exceeds PP in three lakes differing in pH and iron concentration (mean pH 2.3–3.0, 23–500 mg Fe L−1). Bacterial biomass and HP achieved highest values in the most acidic, most iron-rich lake, whereas PP was highest in the least acidic lake. HP was often higher than PP (ratio HP/PP up to 11), indicating that planktonic PP was not the main carbon source for the bacteria. HP was not related to PP and DOC, but HP as well as bacterial biomass increased with decreasing pH. Light stimulated the formation of ferrous iron, changed the DOC composition, and increased the HP in laboratory experiments, suggesting that iron photoreduction caused DOC degradation. This may explain why we found the highest HP in the most acidic and most rich lake. Overall, the importance of bacteria in the cycling of matter and as a basis for the whole food web seemed to increase in more acidic lakes with higher iron concentrations.