Dr. Katie Schreiner
Research: My research is primarily focused on organic carbon cycling in terrestrial soils, marine sediments, and aquatic and marine systems, which I study using a variety of organic biomarkers, bulk and compound specific stable isotopes, and radiocarbon. I have studied organic carbon inputs into large-river delta-front estuarine and marine sediment in mary areas around the world, including the Mississippi River estuary in the Gulf of Mexico and the Colville River estuary in the Beaufort Sea north of Alaska. Additionally, I have assisted with water column studies in the Gulf of Mexico hypoxic zone and the Drake Passage north of the Antarctic Peninsula in the Southern Ocean. Currently, my research is focused on studying the flow of organic carbon in terrestrial soils through soil fungal-mediated pathways, in order to determine the role that these important soil microbes play in the formation and stabilization of long-lived organic carbon pools in soils.
Currently at: University of Minnesota Duluth, Large Lakes Observatory
Dr. David Vinson
Research: Overall, my research examines redox processes, biogeochemical transformations, and water-rock interaction in the subsurface. This research spans hydrogeology, isotope geochemistry, water quality, and energy resources. At Northwestern, I am working with Neal Blair on improved tools to understand what actually controls carbon isotope signatures of biogenic methane in coal beds. A major collaborator in this effort is Jennifer McIntosh (U. of Arizona). As part of this research, I am exploring the compound specific carbon isotope signature of acetate, an important biological precursor of methane in coal bed waters, as a tool for understanding the key metabolic pathways of methane production in the subsurface. This is combined with conventional isotope fingerprinting techniques for accumulated end products (methane and CO2). At NU, I was supported by an NSF Earth Sciences Postdoctoral Fellowship.
Research: Through my environmental and chemical engineering education at Northwestern University, I have developed a commitment and passion to producing renewable energy solutions, especially the production of biofuel from novel feedstocks. My research interests have led me to multiple research experiences with biofuel production around the world, including my undergraduate research at Northwestern on biodiesel production from spent coffee grounds and my work with the Tailor-Made Fuels from Biomass (TMFB) Cluster of Excellence in Aachen, Germany. I am an enthusiastic and motivated researcher and engineer with excellent written and oral communication skills.
Dr. Laurel Childress
Research: My research focuses on biogeochemical cycles, specifically the transport, transformation, and burial of organic carbon. Active margins, found at the junction between continental and marine tectonic plates, are characterized by high sediment transport rates and a close proximity between terrestrial sediment source and marine burial. These factors allow active margins to be particularly effective in the burial of organic carbon, resulting in high fidelity records of the terrestrial and marine environment spanning millions of year. Differences through time in the quantity and type of exported organic carbon from terrestrial environments can provide information on past storm frequency, sea level, precipitation regimes, vegetation type, erosion rate, and tectonic uplift.
Additionally my research follows organic carbon into active margin related subduction zones. These regions represent the ultimate sink for sediment and the associated organic matter. To refine global carbon budgets and volatile production in subduction zones I study the transformations and trajectories of organic carbon in laboratory simulations using a high-pressure high-temperature sapphire anvil cell, coupled with Raman spectroscopy.
Research: There is a need for a fast, broad-spectrum organic geochemical tool that only requires small amounts of environmental sample. I have developed a modified online-thermochemolysis method that requires small amounts of sample (~mg), minimal sample preparationand utilizes commercially available tetramethylammonium hydroxide (TMAH) to quantitatively characterize the OC content of vascular plant tissues, sedimentary rocks, soils, and marine sediments using biomarkers. The application of TMAH thermochemolysis as a rapid , broad-spectrum derivatization method for trackingthe geochemical evolution of TOC from watershed sources (e.g. sedimentary rocks and soils) through riverine transport to the marine environment (sink) in the well-studied Waipaoa Sedimentary System, New Zealand has been demonstrated.
My research focuses on understanding the origin, properties, and carbon storage capacity of chitin, a biopolymer found in arthropod exoskeletons and fungal cell walls. In particular, I am interested in the fatty acid content of chitin. Using Gas Chromatography-Mass Spectroscopy, I have identified a non-extractable fraction of fatty acids left in purified shrimp shell chitin even after extensive organic solvent extraction. Currently I am working to decipher the chitin chromatogram to better understand the structural relationship between the fatty acids and the chitin itself.
The Fatty Acid Content of Shrimp Shell Chitin (2015) Undergraduate Research Exposition, Northwestern University — Oral Presentation
My research focuses on bio-methane production from man-made reservoirs, specifically understanding how age and depth of the sediment affects bio-methane production. Energy from hydroelectric power sources is often considered to produce zero emissions – yet this is not the case. As land is flooded, the submerged sediment becomes an anoxic environment, where organic carbon is biodegraded into methane. Understanding bio-methane production from man-made reservoirs will be crucial to determining the correct energy future for our country. My research will work to expand this knowledge by understanding how methane production changes as the submerged sediment ages.
I am a junior pursuing major in Integrated Science Program and Materials Science. I am investigating the potential of chitin-degrading fungi to utilize chitin (shell waste from food industry) as a food source. I plan on further studying extraction from strains with the highest lipid content to produce biodiesel.
Yue (Major) Zeng
I am a junior majoring in Civil Engineering and Environmental Science and a research assistant on the IML-CZO project. My research project currently involves developing a FTIR method to quantify the particulate carbonate concentrations in suspended stream sediments.