SS3.10 Ecological Implications of Terrestrial Inputs into Lakes and Ponds
Date: Tuesday, June 11, 2002
Time: 10:30:00 AM
Location: Esquimalt
 
KamjunkeN, Univ. Potsdam, Inst. Biochem. Biol., Potsdam, Germany, kamjunke@rz.uni-potsdam.de
Krumbeck, H, , Brandenburg Univ. Technol., Cottbus, Germany, krumbeck@aol.com
Beulker, C, , Brandenburg Univ. Technol., Cottbus, Germany, obygo@t-online.de
Tittel, J, , Center Environ. Res., Dept. Inland Wat. Res., Magdeburg, Germany, tittel@lake.gm.ufz.de
 
HIGH RATIOS OF BACTERIAL TO PRIMARY PRODUCTION IN ACIDIC MINING LAKES
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Recently flooded coal mining lakes are often very acidic due to the oxidation of iron sulphides. Low concentrations of CO2 and highly pigmented water limit planktonic primary production (PP). But much dissolved organic material (DOM) of mainly allochthonous origin is available for heterotrophic bacteria. We tested whether bacterial production (BP) exceed PP in 3 lakes of different pH in Germany. The highest BP was observed in the most acidic lake (pH 2.3) when compared with lakes of pH 2.6 and 3.0. In contrast, PP was highest in the least acidic lake. It was lower than BP in some cases indicating that PP was not the main carbon source for the bacteria. Bacteria and mixotrophic phytoplankton did not compete for DOM since in laboratory experiments growth rates and glucose uptake of both as well as BP were independent of whether bacteria and algae were incubated separately or together, and bacteria were the main consumers of DOM. Overall, bacteria play an important role in the cycling of matter and as a basis for the food web in acidic mining lakes.