Pallavi Mittal

Plymouth State College

Environmental Biology


Mentor: William H. McDowell, Professor of Natural Resources

Effects of Ultra-Violet on the Breakdown of Dissolved Organic Carbon (DOC) and Dissolved Organic Nitrogen (DON) in the Lamprey River

In all ecosystems, bacteria are the most numerous organisms and through them flows a large fraction of annual primary production. A wealth of evidence shows that refractory dissolved organic compounds in surface waters DOC may be converted into microbially labile compounds by solar radiation in several wavebands.

My research consisted of sampling and analyzing stream water samples from a longitudinal transect of the Lamprey River. I began collecting my samples from upstream, moving onto downstream. I filtered these samples using a 0.7mm pore diameter precombusted GF/F (Glass Fiber/Fine) filter. One liter of this filtered sample is further filtered using a 0.22mm pore diameter nylon membrane filter. This filter removes most microbes, essentially filtersterilizing the sample. All the samples are frozen until analysis for DOC and DON using a Shimadzu Carbon analyzer and Antek Nitrogen detector are done. The second part of my research consisted of putting the 0.22mm filtered water in six quartz bottles. Three of which were put in the sunlight and three of which were kept in the dark. Changes in light intensity and temperature are monitored in the bottles exposed to sunlight. Temperature alone is recorded for the bottles in the dark. Over time I expect to see changes in DOC and DON concentrations due to exposure to UV radiation.

« VIew 1999 McNair Scholars