Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Bonnie Brown


The lack of success in restoring oyster, Crassostrea virginica, populations to Chesapeake Bay and its tributaries has raised many questions about why many restoration efforts have failed. A number of studies have focused on the larval stage of oysters and considered the variables that impact oyster setting behavior in an effort to understand why oyster populations have not recovered. Studies that have examined setting surfaces suggest that biofilms promote oyster larval settlement; however, similar studies with barnacle larvae have found an inhibitory relationship. The present study utilized field-produced biofilms of different ages to determine if natural biofilms inhibit or promote setting of larval oysters. Several aspects of the biofilms where analyzed including biomass, chlorophyll a concentration, percent organic matter, bacterial cell counts, and bacterial community composition. Larval setting was found to increase as biomass and age of biofilm increased. No effects of chlorophyll a concentration, percent organic matter, bacterial cell counts, or bacterial community composition were detected. The predator Stylochus elipticus was observed to have a profound effect on newly set larvae. A new method for enumerating bacterial cells was explored to promote high throughput analysis of biofilm specimens. This method involves applying bacterial suspensions to bio-adhesive slides with subsequent staining and was compared to the standard method of enumeration on filters. The bio-adhesive slide procedure allowed processing of ten times more specimens per slide, resulted in lower background fuorescence, and higher bacterial counts than the standard filter method. The method promoted high throughput while yielding more accurate counts than filters when compared to dilution curves and was found to be useful for direct enumeration of bacteria in laboratory cultures, wastewater, sediments, and biofilms.


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Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

August 2009

Included in

Biology Commons