Sasha Bartels'08

Stream Research
Dartmouth College Department of Biology
Hanover, New Hampshire

Summer 2007

During the summer of 2007 I worked under Celia Chen who is a research associate professor in the Biology department at Dartmouth College and Kathleen Weathers and Nick Baer at Colby-Sawyer College.  The two projects I worked on were on streams around the Connecticut River and on streams around Little Lake Sunapee.

The first project was trying to determine the factors that drive mercury accumulation in stream fish on the White River.  They found in an earlier study that mercury concentrations are higher in fish from low-productivity sites where fish grow slowly. This summer I followed up on their earlier findings by measuring mercury in other food web components (fish prey and algae) and other potentially important predictors of mercury accumulation (pH, temperature, DOC).  To do this used stocked juvenile Atlantic salmon as a field assay of mercury accumulation in streams because I could control the initial location and size of the fish.  Salmon are a threatened species that they are trying to restore to local streams, so I also tracked indicators of salmon performance (survival and growth rates).  I collected samples of fish and other organisms and surveyed water quality and habitat characteristics and prepared samples for analysis. I also spent a good deal of time picking through benthic and drift samples counting and identifying the invertebrates.

The second project was a pilot study on mercury accumulation in aquatic food webs. I did some field sampling in streams in the Lake Sunapee watershed, stratified by dissolved organic carbon (DOC) concentrations. I worked on calibrating and determining the accuracy of chloride probes that we wanted to use to compare high DOC and low DOC streams.  I also sampled on streams in order to calculate discharge on the streams.