SS3.04 Biogeochemistry of DOC/DON in a Watershed Context
Date: Wednesday, June 12, 2002
Time: 11:30:00 AM
Location: Carson B
 
Kaplan, L, A, Stroud Water Research Center, Avondale, USA, lakaplan@stroudenter.org
ChengX, Stroud Water Research Center, Avondale, USA, xcheng@stroudcenter.org
 
DOES THE MOLECULAR COMPOSITION OF DISSOLVED CARBOHYDRATES REFLECT TERRESTRIAL VEGETATION AT THE BIOME-SCALE?
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We characterized the dissolved organic matter in streamwaters to test the hypothesis that variation in terrestrial vegetation at the biome-scale results in similar streamwater chemistries within a biome but differences between biomes. Water was sampled from three streams in each of three different biomes: Eastern deciduous, Southeastern coniferous, and Tropical evergreen. Carbohydrate concentrations and compositions were obtained from the individual monomers within samples following acid hydrolysis. Carbohydrate concentrations ranged from 0.9 to 2 uM in the Deciduous forest streams, from 0.1 to 0.8 uM in the Tropical forests streams, and from 0.3 to 4.6 uM in the Coniferous forest streams. Principal Component Analysis indicated that each biome possesses a generally unique carbohydrate composition, but that streams within biomes have similar structures of complex carbohydrates; Principal Components 1 and 2 explained 71% of the variation within the carbohydrate composition data sets. The mole percent fucose accounted for 14 mole percent of the carbohydrate pool in the Deciduous forest streams, 8 mole percent in the Coniferous forest streams, and 5 mole percent within the Tropical forest streams.