August 27, 2008

Discovering the Harmful Effects of Herbicide

My research experience with Professor Nancy Waters. By Jacquelyn Marchese ’09

This summer, Jacquelyn Marchese ’09 (Basking Ridge, N.J.), who created her own major in computational biology, worked as a Nalven Fellow with Nancy McCreary Waters, associate professor of biology, on research looking at the effects of the herbicide atrazine on invertebrate development. Marchese is a member of the women’s soccer team.

In April, I was awarded the biology department’s Nalven Summer Research Fellowship. An award made possible by the Nalven family, who created the fellowship in honor of the late David Nalven, class of 1988. David was one of Dr. Waters’ summer research students. His memorial fellowship allows two students, each summer, to gain the same immensely beneficial experience that David was able to.

My project focused on the impacts of atrazine, the most commonly used herbicide in the United States. Currently, the legal potable limit, set by the Environmental Protection Agency, is 3 parts per billion (an incredibly small amount). There have already been toxicological studies on atrazine that have shown harmful ecological damage with exposure to even smaller amounts.

With help from Dr. Waters and John Drummond, biology lab coordinator, I designed an experiment that would test the developmental effects of atrazine on invertebrates. The organism of choice was originally the monarch butterfly, but due to unforeseen circumstances with growing a proper food source, my summer project focused on caddisflies.

Caddisfly larvae live in still freshwater (lakes, streams) and are a few centimeters long. Like butterflies, they go through a developmental stage that involves an enclosure stage in a cocoon. However, unlike butterflies, caddisflies live in the cocoon as snails live in their shells; butterfly caterpillars generally spin cocoons right before the time of enclosure. Emerged caddisflies look very similar to moths.

In the experiment, each organism was given a one liter container. Each of these containers required sediment and decomposed leaf litter, both field collected at Merrill Creek Reservoir in Washington, N.J. Once the caddisflies were situated in the lab, the experiment began. Each week, half of the caddisflies were exposed to 1 ppb level of atrazine, while the others were used as controls. Eventually, many became enclosed and finally emerged from the cocoons. As caddisflies are a native species, all were released into the environment. At the moment, the results of the experiment are preliminary.

I am very grateful for the opportunity given to me through the biology department and the Nalven family. The amount that I learned about science, research, and myself was priceless. I feel as if this experience truly enhanced my college experience and helped me grow as a student. I will undoubtedly benefit from this fellowship in my coming years after graduation.

  • Biology
  • Undergraduate Research

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