Current Research

Organic Geochemical analyses of Taylor Valley Lakes sediments, microbial mats, and ice

Caroline Jaraula, PhD Fellow

My study is part of the long-term ecological research (LTER) program that investigates ecological processes over long temporal and broad spatial scales. The LTER site is in the largest ice-free region of Antarctica, McMurdo Dry Valleys, and is the coldest and driest, representing an “end-member” in the spectrum of ecological niches. Taylor Valley, in particular, hosts lakes that differ from each other, chemically and physically: Bonney, Chad, Hoare and Fryxell. These lakes vary from continental- to coastal-type of environmental influences. As a result, these four lakes have different physico-chemical properties and have varying histories and responses to changes in environmental conditions. My research uses organic geochemical tools and analyses in the lakes to detect biogenic and anthropogenic markers and trace their source(s).
As a helicopter crashed on the perennial ice cover of Lake Fryxell on January 17, 2003, aviation fuel and small amounts of hydraulic fluid, synthetic transmission fluid, and synthetic engine lubricant were spilled. Tracking the residual composition of these fluids in meltpool waters, sediments and ice can help us monitor and identify processes that affect their composition. Some of the processes help to lessen their abundance in the ice cover that is important in preventing these contaminants from entering the lake.
The biomarker type, distribution, and isotopic character in recent water, sediment or microbial mat samples from the lakes are correlated to their parent biomolecules. These molecules are linked to specific organisms or biosynthetic pathways from LTER monitoring of these sites or from known physical-chemical conditions, which these biomolecules persist and are preserved. Knowledge of the “recent” environment in Taylor Valley will also be compared to biomarkers preserved in core sediments representing up to 50,000 years of accumulation in the lakes. Use of lipid-based proxies can help us identify paleoecological and paleoenvironmental information useful in interpreting regional paleoclimate conditions and ecological responses.

Posters:
Evaporation experiment: Differentiation between molecular composition Evaporation of biodegraded and evaporated spilled fluids on the ice cover of Lake Fryxell, Antarctica

Links:
http://www.mcmlter.org/
http://www.uic.edu/depts/geos/people/students.html