Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Paul Bukaveckas

Second Advisor

Rima Franklin

Third Advisor

John Anderson

Fourth Advisor

Len Smock


Empirical studies have shown that algal- and detrital-based food web components are coupled in many pelagic systems as algal carbon enhances bacterioplankton production and growth efficiencies. Such phyto-bacterioplankton coupling impacts carbon flow through plankton food webs, yet the extent of coupling is poorly understood in systems receiving large amounts of allochthonous carbon. To investigate this issue, bacterioplankton abundance (BA) and community composition were compared to chlorophyll a concentrations and phytoplankton production in the tidal-freshwater James River (VA). BA averaged 107 cells mL-1 and was significantly related to chlorophyll a, phytoplankton production, and DOC concentrations. Analysis of DOC quality using fluorescence spectroscopy revealed that the fulvic DOC fraction was dominated by allochthonous compounds. However, estimates of DOC C:N and DOC turnover rates indicated that DOC was more labile in the lower part of the study reach where BA was highest. T-RFLP analysis of 16s rDNA showed that bacterioplankton community composition significantly varied between the upper and lower portions of the sampling reach. These findings suggest that coupling of food web components is an important pathway affecting carbon cycling within the tidal-fresh water James River.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

May 2009

Included in

Biology Commons