Friday July 21, 2017 @2 pm
Presenter: Dr. Birgit Hagedorn (University of Alaska Anchorage)
A research faculty member is currently being recruited to run the new Multi-collector Inductively Coupled Mass spectrometer (MC-I-CPMS) facility (funded by NSF and to be opened in the Fall 2017) in the new Engineering building on the UAF campus. This seminar will allow one of the candidates, Dr. Birgit Hagedorn, to show case here experiences and applications using this type of instrumentation to address environmental research questions. These types of techniques can be applied to an array of questions in a wide range of disciplines (biology, geology, marine science, archeology, paleoecology).
Abstract: Subglacial environments are at the interface between solid ground and overlying ice. They can be frozen to the ground (cold based) or above freezing and water saturated. The presence of liquid water together with nutrients provided by weathering of soil and rock creates a geochemically active environment that provides a habitat for microbes and nutrient source proglacial waters, estuaries, and oceans. Subglacial environments are not easily accessible to direct observation and studies often rely on sampling the two endmembers of the glacial system: (1) Meltwater on top of the glacier and (2) bulk outflow. A common approach to characterize subglacial biogeochemical processes and microbial communities is to sample both areas over an entire season and extract the information by determining the difference between both environments. There are only a few studies that sample directly the subglacial environment via bore holes that reach the glacial bed.
Presented here are outcomes of a 3 year project in NW and SW Greenland where geochemical and isotopic data were collected on water and solid material from bulk outflows and glacier surfaces to identify subglacial processes during seasonal changes. The focus of the study was to characterize and quantify the micronutrient iron and microbial communities in subglacial environment by sampling the two bulk outflows of the Greenland Ice Sheet. In addition we were able to collect samples during the extreme melt event of the Greenland Ice Sheet in 2012 were about 97% of the GrIS surface was molten for a few days. Geochemical and Sr isotope data will be presented that give insights about subglacial hydrology, source areas and the effect of such extreme events on nutrient fluxes. Future planned and pending research projects will be described that are follow-ups of this study and of a preliminary study on mercury cycling in Alaskan glacier.