Tuesday, September 19, 2017 GSA Luncheon

 Topic "Mercury Cycling in the Matanuska Glacier"

Noon Luncheon 11:30-1:00 pm

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LUNCHEON ABSTRACT

Mercury (Hg II) and especially methylmercury (MeHg) is increasing in a number of marine species in the Arctic. In addition to modern atmospheric mercury deposition there is evidence that Glacier have accumulated atmospheric derived gaseous pollutants over time making them to a potential source for mercury. This talk presents first data that towards a better understanding of mercury deposition, biogeochemical cycling export and in a Glacier - Estuary system.

We choose the Matanuska Glacier for a case study to investigate the biogeochemical cycling of mercury in Glaciers. The glacier is located in the Chugach Mountains in south central Alaska about 138 km north of Anchorage. It is a large valley glacier that flows north from the Ted Stevens Ice Field and is approximately 45 km long and ranges in width from approximately 3 km near the equilibrium line to about 5 km at the terminus. The glacier features over-deepening creating super-cooled subglacial water which outbursts in vents and crevasses on glacier surface along the terminus. This water resembles meltwater that is routed through
subglacial cavities and distributed and channelized systems and can be easily sampled from the glacier surface in spring and throughout the summer.

Samples of snow, surface meltwater and subglacial water and suspended sediment were analyzed for total mercury concentration and monomethylmercury (MeHg) in combination with water quality and microbial DNA analysis. We also collected samples along Matanuska River and Cook Inlet to identify potential sources and sinks of total mercury and methylmercury in this connected system. A first order mercury cycling model is developed based on mass balance and microbial data.

SPEAKER BIOGRAPHY

Dr. Birgit Hagedorn, Sustainable Earth Research, LLC

Dr. Hagedorn holds a Diploma in Mineralogy and Geophysics and a PhD in isotope Geochemistry from Germany.
Throughout her entire career she is working in the field of environmental geochemistry with an strong
emphasize in the Arctic and Antarctic. She worked for 4 years with researcher at University of Washington at
the Quaternary Research Center and managed for 11 years an interdisciplinary analytical research laboratory
at the University of Alaska Anchorage.

Most of her research focuses on nutrient and contaminant transport in permafrost, river and glacier systems. She has more than 25 years of field experiences in remote locations such as Antarctica, Greenland, Siberia and northern Alaska where she trained students in sampling and field methods. But she has also worked in other climatic and geologic settings including the Himalayas, western US and central Europe.

Over the past decade Dr. Hagedorn has worked on a large variety of environmental projects related to human activity in urban and rural places. She gave environmental sampling workshops in Barrow and Anchorage and several short workshops on water quality at conferences and community meetings in Alaska. Dr. Hagedorn recently started her own company with training workshops and consulting in environmental projects.

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