Quantifying microplastics in water and sediment along river-marsh transects in the Choptank River

Abstract

Plastic began as useful material with many different applications. Due to its widespread production and consumption, its utility and durability are now also contributing to its status as a major environmental and human health contaminant with a long and mostly unknown lifecycle. This thesis first quantifies microplastics in the water and sediment of the Choptank River, a major tributary of the Chesapeake Bay. Microplastics are defined as particles smaller than 5mm that are produced as precursors to larger plastic material or occur when plastic items degrade. We explore the effect of differences in microplastic concentrations due to locations of transects along and positions across the river, seasonality, and interactions with vegetation. In the water column, abundance of microplastics was higher in the marshes flanking the river than the deeper channel at all transects and in all seasons. In the sediment, abundance is higher at subtidal than intertidal sites. The second part of the thesis explores the potentially novel microbial ecosystem(s) generated by the ubiquitous presence of plastic and the possibility of altering metabolic processes, subsequently restructuring biogeochemical flows.