ELEMENTAL COMPOSITION AND NUTRIENT EFFECT ON THE UPTAKE AND METABOLISM OF DISSOLVED ORGANIC CARBON BY BACTERIA FROM A TEMPERATE REGION RIVER

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.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environmental Sciences

Year dc:date.available

2009

Author dc:creator

• Stuart, Anne

Contributors dc:contributor

• S. Leigh McCallister

• Organic Carbon
• Fate and Transport
• Environmental Sciences
• Physical Sciences and Mathematics

Statement dc:rights

• © The Author

Identifier

https://scholarscompass.vcu.edu/etd/11

OAI identifier oai:identifier

oai:scholarscompass.vcu.edu:etd-1010