The characterization and bioavailability of dissolved organic carbon in deep subsurface and surface waters

We characterized and compared the bioavailability of chemical fractions of dissolved organic carbon (DOC) from deep wells at the US Department of Energy Savannah River Plant (SRP) site with that from South Carolina surface waters. Experiments with three bacterial cultures (Corynebacterium sp., Pseudomonas sp., and a bacteria included isolated from the surface water) indicated that the bioavailability of the carbon in the near surface water may be limited by inorganic nutrients. Associated with well-defined organic compounds. The purpose of this preliminary investigation was to improve our understanding of the organic matter in groundwater by characterizing the natural organic matter in water recovered from different formations in the Deep Probe Subsurface Microbiology program and by determining if the natural organic carbon can support growth of bacterial populations. The characterization was directed at elucidating the properties of of dissolved or colloidal organic matter that are relevant to the transport and mobility of the organic matter (and contaminants sorbed to the organic matter) and that may also be relevant to the potential role of organic matter in groundwater as a nutrient source supporting microbial productivity in the deep subsurface. A secondary objective of this study was to determine the factors limiting microbial growthmore » in surface waters and near surface groundwaters and to determine the response of the microbial community to a mixing of these waters.« less