| |
Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Land/Water Interfaces
EFFECTS OF SEASONAL HYDROLOGY ON MICROBIAL COMMUNITIES AND WATER CHEMISTRY OF FLOODPLAIN POOLS IN A SOUTHEASTERN U.S. RIVER.
N.K. Weibell and A.K. Ward. Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487
Interactions between rivers and their floodplains have become an increasingly important component of our understanding of lotic ecosystems. The Sipsey River, an unimpounded river in northwestern Alabama, includes an extensive forested, floodplain swamp that is inundated most of the winter and then flooded by smaller events episodically throughout the warm season. In this study, we examined the effects of inundation on water chemistry and microbial features of floodplain water in comparison to river water in the main channel. Seasonal sampling of floodplain and river water revealed increased concentrations of dissolved organic carbon (DOC) (>15 mg C L-1) in isolated pools by the end of fall compared to lower concentrations (<10 mg C L-1) in the main channel. After early winter inundation of the floodplain by river water, DOC levels in floodplain water remained higher than main channel water, and bacterial productivity in the inundated floodplain was twice as high as in the main channel. These and other results supported a working hypothesis that floodplain pools act as a DOC source and a hotspot for bacterial productivity during the warm summer and fall months, and that this role continues even after inundation and reconnection of the floodplain with the main channel occurs.
|
|
