SS3.10 Ecological Implications of Terrestrial Inputs into Lakes and Ponds
Date: Tuesday, June 11, 2002
Time: 11:30:00 AM
Location: Esquimalt
SinsabaughRL, University of Toledo, Toledo, USA,
Findlay, S, G, Institute of Ecosystem Studies, Millbrook, USA,
Perceptions of the role of DOM in aquatic ecosystems have completely inverted in 30 years. In the old paradigm, DOM was a residue of trophic interactions. Similarities in concentration and composition across systems were taken as evidence of inertness. In the new paradigm, DOM is perhaps the most interactive component of aquatic ecosystems: similarities across systems emerge from the interactivity of myriad biogeochemical processes. This view recasts the issue of terrestrial DOM as a contributor to trophic stability. Because microbial metabolism is highly responsive to DOM changes, trophic stability implies that external inputs are compositionally stable. External inputs are products of the interaction between flow paths and landscape elements. The compositional stability of these inputs increases with the spatiotemporal displacement of the source from the sink. Thus the stabilizing effect of terrestrial DOM on a target system depends on the size and displacement of the sources.