CS26 Organic Carbon Dynamics
Date: Thursday, June 13, 2002
Time: 9:45:00 AM
Location: Carson C
 
MarxsenJ, Limnologische Fluss-Station des Max-Planck-Instituts fuer Limnologie, Schlitz, Germany, jmarxsen@mpil-schlitz.mpg.de
Katzner, A, , Limnologische Fluss-Station des Max-Planck-Instituts fuer Limnologie, Schlitz, Germany, akatzner@mpil-schlitz.mpg.de
 
FREE DISSOLVED CARBOHYDRATES IN DIFFERENT HABITATS OF THE BREITENBACH, A SMALL UPLAND STREAM IN CENTRAL GERMANY
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Dissolved carbohydrates are important components in freshwaters, because they provide a significant source of C and energy, especially to heterotrophic bacteria. The development of the technique of HPLC-PAD combines high sensitivity and accuracy. This allowed the determination of the composition of the pool of dissolved mono- and disaccharides in the water of different habitats of a small upland stream: in stream water, interstitial water from different depths, and groundwater adjacent to the stream. 15 different saccharides were determined. Only five were regularly found in stream water: ribose, saccharose, fructose, glucose, and arabinose, - at average concentrations between 5 and 20 nmol/L and maximum concentrations up to about 100 nmol/L. The concentrations in interstitial water were distinctly higher: average 49 to 244 nmol/L, maximum up to 900 nmol/L. The annual fluctuations of the saccharides show higher concentrations at summer time and during autumn and lower concentrations during winter. This observation of a temperature dependent occurrence of mono- and disaccharides can be taken as an indication of the origin of most of the compounds as products of biological activity.