DOI
https://doi.org/10.25772/6PG2-H489
Defense Date
2009
Document Type
Thesis
Degree Name
Master of Science
Department
Environmental Sciences
First Advisor
S. Leigh McCallister
Abstract
Rivers are arteries that connect land and sea, and provide a conduit and reactor for allochthonous and autochthonous organic carbon sources (OC) delivered to the coastal ocean. In comparison to marine waters, inland waters quantitatively represent only a fraction of the marine system; however, their importance to global C cycling maybe disproportional to its actual size. Inland systems are subject to multiple sources of OC (autochthonous and allochthonous) that vary individually in space and time with respect to their concentration and potential bacterial bioavailability. This study investigates the impact of high and ambient inorganic nutrient concentrations on the bacterial bioavailability of potential exogenous and internal organic C sources to bacterial decomposition in the Chickahominy River using a long term incubation approach. In addition the elemental composition of each organic C substrate is investigated as a predictor of OC source bioavailability. The results of sole source incubations showed that autochthonous SAV sources were the most labile whereas soil derived OC was the least bioavailable, irrespective of nutrients. However, leaf litter sources showed relatively high bioavailability. The C:N ratios of SAV, Peltandra virginica, Botryococcus braunii, leaf litter, and soil (19.6, 12.4, 15, 29.7, 8.4 respectively) oppose historically accepted theory that autochthonous OC sources with low C:N ratios are a more bioavailable substrate for bacteria than allochthonous OC substrates with higher C:N ratios. The results of this study should provide a better of understanding of the interaction between inorganic nutrients and OC decomposition from allochthonous and autochthonous sources as well and potentially allow model prediction of OC lability based on its elemental signature.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
August 2009