Organic and Isotope Geochemistry Group
The complex mixture of organic molecules in streams and rivers holds clues about a wide variety of natural and human processes occurring within watersheds. By determining the identity and origin of these molecules, the scientists in this laboratory can both expand scientific understanding of natural cycles of energy (carbon) and nutrients within the ecosystem and inform decision-makers about the sources and impact of human contamination on water quality.
Department listing
Dr. Anthony K. Aufdenkampe, Associate Research Scientist Profile | Email
Stephanie Dix, Geochemist, Level III Profile | Email
Steve Hicks, Sensor Network Development Engineer Profile | Email
Dr. Diana Karwan, Postdoctoral Researcher Profile | Email
Dave Montgomery, Research Watershed Manager Profile | Email
Fee for Service Sample Analyses (email for price quote)
- Polycyclic Aromatic Hydrocarbons (PAH)
- Sewage indicators caffeine, fragrances and fecal steroids
- Amino acids
- Carbon and nitrogen isotopes in solids – %C, %N, δ13C and δ15
- Dissolved Organic Carbon (DOC) in water – concentration and δ13C
- Dissolved Inorganic Carbon (DIC) in water – concentration and δ13C
- Dissolved gases N2, O2, Ar – concentrations, δ15N and δ18O
- Dissolved nitrate isotopes – δ15N and δ18O
- Mineral surface area and porosimetry analysis
- Alkalinity or Acid Neutralizing Capacity (ANC)
Laboratory Instrumentation
- Thermo-Finnigan
DeltaPlus XP Isotope Ratio Mass Spectrometer (IRMS) equipped with a dual
inlet system and interfaced in continuous flow mode to:
- a Costech 4010 CHNS-O Elemental Analyzer (EA);
- an OI 1010 TOC-TIC Analyzer (TIC-TOC, shared with the Biogeochemistry group)
- a Thermo-Finnigan Gasbench II with dual cryogenic traps, configured to analyze dissolved gases CO2, N2, O2, Ar, N20.
- Agilent 6890 series Gas Chromatograph (GC) coupled to a 5973 series Mass Selective Detector (MSD)
- Agilent 6890 series Gas Chromatograph (GC) coupled to a Flame Ionization Detector (FID) and interfaced with an optional cryogenic focusing system for two-dimensional chromatography.
- Agilent 1100 series High Pressure Liquid Chromatograph (HPLC) with diode array and fluorescence detectors and an autosampler (shared with the Biogeochemistry group)
- Micromeritics TriStar 3000 surface area and porosimetry analyzer;
- Bruker Tensor 27 Spectrometer with a Pike XY Autosampler accessory for automated Diffuse Reflectance Infrared Fourier Transform (DRIFT);
- Mettler-Toledo DL50 Autotitrator with Rondolino autosampler.
- Mettler-Toledo UMX2 Ultra-Microbalance.
Laboratory Facilities
Stroud Water Research Center is housed in a 24,820-square-foot combined research and teaching facility. Research laboratories, including a greenhouse and two wet laboratories that are continuously supplied with stream water, occupy 10,200 sq. ft. of space. Organic and Isotope Geochemistry laboratories housing the above instrumentation occupies approximately 1200 sq. ft.
In addition, a 400 sq. ft. “14C Clean Lab” was constructed in an outbuilding to enable contamination-free processing of organic matter samples for natural abundance radiocarbon analyses at national centers for Accelerator Mass Spectrometry (AMS).
Stephanie A. Dix
Geochemist, Level III, 2006 to present.
Education: B.S. in Biology, concentration in Marine Biology, Millersville University, 2005.
Stephanie is the lab manager for the Organic Geochemistry group. She is in charge of operating and maintaining analytical instrumentation, which includes an isotope ratio mass spectrometer (IRMS) coupled with an elemental analyzer and dissolved organic carbon analyzer to measure stable isotopes of carbon, nitrogen and oxygen. The IRMS is also coupled with a GasBench II to measure isotopes of dissolved gases (N20, CO2, N2, O2, and Ar). She also maintains and operates a surface area analyzer to measure the surface area of soils, and a Fourier Transform infrared spectrometer. Stephanie manages field sampling trips, interns, and sample processing for the organic geochemistry lab.
Steve Hicks
Sensor Network Development Engineer
Education: B.S. in Electrical Engineering, University of Memphis, 2000.
Steve has designed and implemented a network of environmental sensors that will be installed throughout the study watersheds. The network will consist of existing sensor and wireless technologies as well as custom sensor devices developed specifically for the CZO to record a variety of environmental measurements.
Dr. Diana Karwan
Postdoctoral Researcher
Education:
Ph.D., Yale University, School of Forestry & Environmental
Studies, 2010.
M.Phil., Yale University, Graduate School of Arts & Sciences, 2006.
M.E.Sc., Yale University, School of Forestry & Environmental Studies, 2004.
B.S., University of Michigan, School of Natural Resources & Environment, 2000.
Diana is a postdoctoral researcher in the Christina River Basin Critical Zone Observatory (CRB CZO). She investigates the movement of water and particulate material through watersheds. In order to quantify the origin of suspended material, she conducts field samplings for soil, sediment, and stream water. She also conducts chemical analyses of these samples for mineral composition and surface area, cosmogenic radioisotopes, and stable isotopes of carbon and nitrogen. View CV
Dave Montgomery
Research Watershed Manager
Education: B.S. Biology, Environmental option, Millersville University, 1997.
Dave installs, oversees, and maintains research watershed infrastructure including: field instrumentation and sensors; sampling installations such as wells, lysimeters, piezometers and ISCO samplers; support infrastructure such as electrical service, pumps and pipes. He performs routine maintenance, calibration, and data collection of or from field instruments. Dave also maintains communications with landowners and farm managers in the research watersheds.
