Environmental Science & Technology Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2748

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SPATIAL AND TEMPORAL VARIANCE OF MICROBIAL WATER QUALITY IN TWO MARYLAND IRRIGATION PONDS
(2019) Kierzewski, Rachel Annette; Hill, Robert; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Farm ponds must be regularly sampled for Escherichia coli (E. coli) concentrations to evaluate the health risks of using pond water for irrigation. However, no guidance is available regarding sampling locations and/or irrigation pump placement. We hypothesized that there exists spatial and/or temporal patterns of E. coli concentrations across ponds. To test this hypothesis, we sampled two irrigation ponds in Maryland biweekly during the summers of 2016 and 2017. Results from data analysis of mean relative differences and Spearman correlation coefficients are presented. Empirical orthogonal functions indicated spatial patterns of Log E. coli concentrations were temporally maintained. More sample variance existed over time in the pond interiors versus near shore locations. Furthermore, larger patterns of sample variance existed within the spatial analysis variance versus the temporal analysis variance over both ponds for this study. Therefore, the spatio-temporal E. coli variance may have significant impacts on sampling and pump intake locations.
Toward the Development of Integrated Oyster-Algae Aquaculture in the Chesapeake Bay
(2014) Ray, Nicholas; Kangas, Patrick C; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Oyster aquaculture is a rapidly expanding industry in the Chesapeake Bay. Experiments were conducted to investigate the biogeochemical impact of a commercial oyster aquaculture facility on downstream waters at a facility on Maryland's Eastern Shore. An algal production system (ATS) was installed at the facility to assess the potential for bioremediation and algal production in an integrated multi-trophic aquaculture system (IMTA). Results of the experiments showed an increase in available ammonia downstream of the aquaculture facility, coupled with decreases in dissolved oxygen and total phytoplankton. The algal production system demonstrated an average productivity rate of 82.8 g/m2*day-1, a nitrogen (N) removal rate of 9.6 gN/m2*day-1, a phosphorus (P) removal rate of 0.20 gP/m2*day-1, and harvests consisted of an average of 7.8% organic content. Productivity and N and P removal rates from this study are higher than other systems tested in the Chesapeake Bay region at sites without an aquaculture facility.