Environmental Sciences Commons^™

Nitrous Oxide Emission From Denitrification In Stream And River Networks, Jake J. Beaulieu, Clay P. Arango

All Faculty Scholarship for the College of the Sciences

Nitrous oxide (N₂O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N₂O via microbial denitrification that converts N to N₂O and dinitrogen (N₂). The fraction of denitrified N that escapes as N₂O rather than N₂ (i.e., the N₂O yield) is an important determinant of how much N₂O is produced by river networks, but little is known about the N₂O yield in flowing waters. Here, …

Spatial And Temporal Patterns In The Microbial Diversity Of A Meromictic Soda Lake In Washington State, Pedro A. Dimitriu, Holly C. Pinkart, Brent M. Peyton, Melanie R. Mormile

All Faculty Scholarship for the College of the Sciences

The microbial community diversity and composition of meromictic Soap Lake were studied using culture-dependent and culture-independent approaches. The water column and sediments were sampled monthly for a year. Denaturing gradient gel electrophoresis of bacterial and archaeal 16S rRNA genes showed an increase in diversity with depth for both groups. Late-summer samples harbored the highest prokaryotic diversity, and the bacteria exhibited less seasonal variability than the archaea. Most-probable-number assays targeting anaerobic microbial guilds were performed to compare summer and fall samples. In both seasons, the anoxic samples appeared to be dominated by lactate-oxidizing sulfate-reducing prokaryotes. High numbers of lactate- and acetate-oxidizing …

Historical Changes In Mid-Water Stands Of Common Reed In The Winnebago Pool Lakes, Wisconsin, Anthony O. Gabriel, Leo R. Bodensteiner

All Faculty Scholarship for the College of the Sciences

Despite the tolerance of common reed grass to environmental extremes, mid-water stands in the Winnebago pool lakes of central Wisconsin appear to be diminishing. Formerly occupying shoreline locations, water level manipulations subsequent to dam construction beginning in the 1850's have isolated reed stands off shore. These stands have persisted but casual observations indicate that stand size has been declining. To address this perception we obtained an approximately decadal series of aerial photographs dating back to 1937 for four stands in Lake Poygan. Annual records were available for 1986–94. Using image analysis software, we determined shape and size metrics. Changes in …

Effect Of Deforestation By The Douglas-Fir Tussock Moth On The Quality Of Streamflow And Stream Productivity Parameters, Martin Ed Hicks

All Master's Theses

The purpose of this study was to determine if deforestation by a recent outbreak of Douglas-fir tussock moth and logging of such deforested timber has had any effect on stream water quality. To determine this, seven different watersheds of three types were examined. The three types were: undamaged watersheds as controls, watersheds with deforestation and watersheds with deforestation where the timber was subsequently logged. Twenty-four variables were used to determine water quality. Included were seven biological and seventeen chemical variables.

In general, the results indicate only seasonal fluctuations and differences between watersheds due to inherent properties of individual watersheds. Increased …