Tuesday, June 5, 2007
527

Effects of leaf litter species on microbial respiration: Implications of riparian forest composition on in-stream oxygen demand in a coastal plain blackwater stream

Andrew S. Mehring1, George Vellidis2, Cathy Pringle1, Kevin A. Kuehn3, R. Richard Lowrance4, and Amy D. Rosemond1. (1) Institute of Ecology, University of Georgia, Athens, GA 30602, (2) Biological and Agricultural Engineering, University of Georgia, Tifton, GA 31794, (3) Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS 39406, (4) Southeast Watershed Research Lab, USDA-ARS, Tifton, GA 31794

Heavily-forested blackwater streams in North America’s coastal plain are known for having low dissolved oxygen (DO) and for receiving large inputs of organic matter.  Respiration rate, often expressed as oxygen uptake, is known to be affected by differences in leaf litter species.  We propose that DO in southeastern coastal plain blackwater streams is influenced not only by quantity but also by quality of leaf litter inputs.  A preliminary study examined differences in microbial respiration rates among leaves of three riparian tree species in Georgia's coastal plain.  Mesh bags containing leaves of red maple (Acer rubrum var. trilobum), water oak (Quercus nigra), and Ogeechee tupelo (Nyssa ogeche) were incubated in a third-order reach of the Little River.  Litter bags were sampled bi-weekly to determine microbial biomass, respiration rates, and breakdown rates of leaves.  Tree species, temperature, and length of incubation affected microbial respiration rates (p < 0.05), with microbes on tupelo leaves consuming the most oxygen.  Tupelo leaves broke down more rapidly than leaves of other species, and their effects on DO levels may be greater initially, but short-lived compared to more recalcitrant leaf litter.  Efforts to isolate the effects of other species and fit data to the reach-scale are underway.

See more of Poster Session - Organic Matter Processing
See more of Contributed Sessions

See more of The NABS 55th Annual Meeting