Summer Science Research at Bryn Mawr

'Jones, L. Camille' Archive

Coulometric analysis of a sediment core from Swiftcurrent Lake, Glacier National Park, Montana

Posted May 10, 2010

Glaciers fluctuate in response to decadal or centennial climate trends as opposed to shorter seasonal or annual climate anomalies creating environmental records in glacial ice and sediment reflect long term environmental trends. Sediment records of organic and inorganic carbon can serve as a proxy for recent anthropogenic and Holocene environmental changes in the park. In this study, carbon content of the Swiftcurrent Lake cores will be measured by coulometry. Organic carbon content reflects bioproductivity in the lake and surrounding area while inorganic carbon in the lake sediment indicates presence of minerals like calcite or dolomite. Two 5 meter lake cores were collected in Swiftcurrent Lake in 2005. Swiftcurrent is the third lake in Swiftcurrent Valley that collects meltwater from Grinnell Glacier and is the most accessible to park visitors. One Swiftcurrent core was sampled at every centimeter for coulometry. The core samples are estimated to be 3% carbon which is likely a mix of limestone sediment and organic material. The sedimentation rate is approximately 52mm/year and the core represents approximately 10,000 years. Park visitors’ presence at the Lake may be detectable in the first five centimeters of the core because or increased human activity since the 1915 completion of a hotel on the shore of Swiftcurrent Lake.