2008 Projects

Picture of Jazlen Samboy '08.Jazlen Samboy '08, Honors Thesis Research: "An Examination of Incipient Speciation in the Form of Behavioral Isolation between Pairs of Populations Experiencing Strong Selection in Different Directions in Drosophila melanogaster." Jazlen examined four pairs of populations in which one population of each pair was under strong selection for DDT resistance, while the other was maintained as an unselected control. The members of each pair were separated (no gene flow between them) for 50 or more years, which is equivalent to 860-1300 generations in fly time. Evolutionary genetic theory proposes that such pairs of populations should experience changes in combinations of alleles at a variety of genes that cause them to diverge in numerous traits. When brought back together, adults may preferentially mate with members of their own population because of subtle changes in courtship behaviors. Such non-random mating is characteristic of the behavioral isolation that is commonly found between species. Faculty Adviser: Phil Barnes

Picture of Adam Campos '08.Adam Campos '08, Honors Thesis Research: "Changes in Brackish Marsh Vegetation and Macrofaunal Communities Following Phragmites australis Control." Adam participated in summer field work on tidal marshes with a team of faculty and students. For his thesis, he compared data on vegetation and populations of invertebrates and fish in control marshes and marshes that were restored by eradication of an invasive plant (Phragmites). The results should have shown whether marsh restoration projects sponsored by The Nature Conservancy and the Connecticut Department of Environmental Protection were effective in restoring the biological diversity and productivity of marshes. Faculty Advisers: Scott Warren and Robert Askins

Picture of Adrian Idrizi '08.Adrian Idrizi '08, Honors Thesis Research: "Characterization of Denitrifier Diversity in Salt Marshes by Determining Terminal Restriction Fragment Length Polymorphisms of nirS Genes." Adrian used DNA fingerprinting methods to characterize the denitrifier community based on the gene for dissimilatory nitrite reductase (nirS). Denitrifying bacteria play an important role in the global nitrogen cycle by converting oxidized forms of nitrogen back to atmospheric nitrogen gas. Nitrogen plays a tremendously important role in the biogeochemistry of coastal systems where inputs of nitrogen can stimulate primary production and create eutrophic conditions. Despite the broadly accepted role that microbes play in nitrogen cycling in coastal habitats, little is known about direct and indirect controls on the microbial communities responsible for nitrogen cycling. Faculty Adviser: Anne Bernhard

Picture of Rachel Zwick '08.Rachel Zwick '08, Honors Thesis Research: "Diversity of Denitrifying Bacteria in Salt Marsh Sediments Based on Sequence Analysis of the nirS Gene." Rachel's main focus was identifying how diversity of denitrifiers changes with sediment depth. Denitrifying bacteria convert oxidized forms of nitrogen back to atmospheric nitrogen gas and mediate the loss of nitrogen from coastal ecosystems where nitrogen plays an important role in regulating productivity. Rachel used DNA sequences of the dissimilatory nitrite reductase gene (nirS) to characterize the denitrifying communities. These genes serve as functional markers, and are responsible for generating the enzymes necessary to reduce nitrite to nitrous oxide and then to elemental nitrogen. Faculty Adviser: Anne Bernhard

David Marshall '09, Independent Study: "Bacterial Diversity Patterns along Latitudinal Gradients." David studied whether bacterial diversity decreased along increasing latitudinal gradients, a well-known ecological pattern of biodiversity observed among many macroorganisms. David compiled data from the literature to determine whether there was evidence to support this common ecological pattern among bacteria. He used the ribosomal RNA gene as a diversity marker.

Faculty Adviser: Anne Bernhard

Picture of Alex McCorkle '10.Alex McCorkle '10, worked on the effects of natural ice nucleating bacteria on the freezing tolerance in the ribbed mussel Geukensia Demissa. To do this he characterized identified ice nucleating bacteria isolated from the mantel fluid from the mussels. He was to determine if the bacteria influenced overall survival and if tissues had less damage when frozen in the presence of the bacteria. Cell death was to be assayed using two fluorescent markers. One emits red light when inside a dead cell. The other emits green light when inside a live cell. Faculty Adviser: Steve Loomis

Picture of Corrine Folsom, M.A. candidate, and Visna Ngov '07. Picture of Stephen Rossiter '09 and William Karis '09.Stephen Rossiter '09 and William Karis '09, (bottom photo, left to right) and Corrine Folsom, M.A. candidate, and Visna Ngov '07, (right photo) completed standardized surveys of birds along power line corridors. They also monitored nest success of prairie warblers and field sparrows along a power line. They set up laser-triggered cameras at nests to identify predators that take eggs and nestlings. Their goal was to assess the importance of the low vegetation along power lines as nesting habitat for several declining species of birds. The results of this study can be directly applicable to improving conservation along power line corridors, providing data on what types of vegetation management are likely to enhance biological diversity. These same management recommendations also would apply to nature preserves and other conservation lands that are being restored for grassland and shrubland species.

Faculty Adviser: Robert Askins

Contact Information:



Email aeber@conncoll.edu

Biology Department
Connecticut College
Box 5213
211 New London Hall
270 Mohegan Avenue,
New London, CT 06320-4196