SS3.04 Biogeochemistry of DOC/DON in a Watershed Context
Date: Wednesday, June 12, 2002
Time: 3:15:00 PM
Location: Carson B
 
SarosJE, University of Wisconsin-La Crosse, La Crosse, USA, saros.jasm@uwlax.edu
Osburn, C, L, NRC-Naval Research Laboratory, Washington, D.C., USA, cosburn@ccs.nrl.navy.mil
Fritz, S, C, University of Nebraska, Lincoln, USA, sfritz2@unl.edu
 
A POTENTIAL LINK BETWEEN DOM SOURCE AND PATTERNS OF PRIMARY PRODUCTION IN PRAIRIE SALINE LAKES
image
Grasslands and converted grasslands (i.e. agricultural land) cover extensive areas in arid and semi-arid regions of the world. Lakes situated in grasslands are usually saline and have high concentrations of dissolved organic material (DOM), typically exceeding 20 mg/L and consisting mainly of uncolored forms. Due to the different nature of DOM in prairie lakes, the role of this material in these systems is presently unclear and may be quite different from that in forest-dominated aquatic ecosystems. We suggest that DOM plays a major role in the regulation of primary production in prairie saline lakes via its effect on nutrient dynamics. We sampled lakes in three areas of the central and northern Great Plains to explore patterns of primary production in these systems. Characteristics of DOM in these systems will be discussed with respect to their influence on these patterns. In particular, we found that the total phosphorus (TP)-chlorophyll relationship in these systems may be linked to the type of vegetation on the watershed, as lakes situated in mixed forest-grassland ecosystems had the most depressed chlorophyll levels in relation to TP.