Spatial patterns in dissolved oxygen and methane concentrations in a prairie pothole wetland in Iowa, USA

The presence of live and dead emergent vegetation alters the microbial metabolism of communities within the water column of prairie pothole wetlands. To demonstrate the effects, dissolved CH4, dissolved O2, plant densities, and litter densities were measured in transects from emergent vegetation to open water zones. O2 concentrations were consistently lower and CH4 concentrations consistently higher in emergent zones. Plant surface cover most likely interferes with gas flux across the air-water interface in the emergent zone, impeding O2 transport into the water column and impeding CH4 transport out of the water column. Either directly or indirectly, the presence of emergent vegetation may alter aerobic and anaerobic metabolism; since wet and dry cycles can result in emergent plant cover from nearly absent to nearly 100%, understanding these dynamics over the long-term will require studies over a range of wetland stages.