McArthur, M. D. University of British Columbia, mikemc@interchange.ubc.ca
Richardson, J. S. University of British Columbia, jrichard@interchange.ubc.ca
Kiffney, P. M. National Oceanographic and Atmospheric Administration, Peter.Kiffney@noaa.gov

 
MICROBIAL UTILIZATION OF DISSOLVED ORGANIC CARBON LEACHED FROM RIPARIAN TREE SPECIES OF DIFFERENT SERAL STAGES
 
Litterfall entering streams from riparian trees represents an important carbon source for aquatic microbial assemblages. Because of light limitation from the forest canopy, microbial production is dependent upon allochthonous inputs for energy and nutrients. Dissolved organic carbon (DOC) leached from forest litter falling into streams may vary in quantity and bioavailability depending on tree species. This study examines leachates from tree species of different seral stages from a coastal rainforest near Vancouver, BC, Canada. Initial results show large variation in the chemistry of leachates from various tree species. DOC concentration in vine maple leachates was found to be roughly 50 mg/g litter/l while western hemlock was close to 25 mg/g litter/l. Tannin content was lower in western hemlock (3-4 mg/ g litter/l) than in vine maple (13-17 mg/g litter/l). This variation in litter leachate chemistry and leads to the prediction that bacteria exposed to the leachates will respond with varying production rates. Leucine uptake measurement of bacterial production rates resulting from different leachate sources is being used to study aquatic microbial production with succession of riparian vegetation. Characterizing the chemistry of the leachates that lead to varying production may provide further insight into what DOC qualities are most important to bacterial production.
 
Day: Thursday, Feb. 4
Time:
Location: Sweeney Center
 
Code: SS33TH0289S