Environmental Gas Flux, Biogeochemistry, and Stable Isotope Analytical and Teaching Laboratory

The Microbiotron is now part of a UW Core Research Facility – the Environmental Gas Flux, Biogeochemistry, and Stable Isotope Analytical and Teaching Laboratory, consisting of the Microbiotron and an instrument lab. The facility seeks to support studies in biogeochemistry and agroecology, primarily on the interactions between soils, microbes and plants, with a focus on gas fluxes in terrestrial systems, the use of isotopic tracers such as ¹³C and ¹⁵N and a suite of analytical capabilities relevant to agroecology and biogeochemical cycling.

1. The Microbiotron is modular system of sealed incubation chambers for carrying out gas flux experiments and analysis: The lab has developed a system, for monitoring changes in gas composition, consisting of small, sealable chambers with ports for gas sampling, coupled to a gas analyzer and valve multiplexer, enabling automated simultaneous monitoring of up to 48 chambers. Gas composition including CO₂, N₂O, CH₄, NH₃ and H₂O can be monitored with Picarro Cavity Ringdown Spectrometer).
2. Stable isotope analysis in solids: The instrument lab has a stable isotope mass spectrometer coupled to a combustion prep unit for analysis of soil, plant or animal tissue for determination of delta-¹⁵N or delta-¹³C, as well as total C and N (Europa 20-20 with ANCA-GSL).
3. Soil and plant characterization: The lab has capabilities to determine total C and N (by combustion elemental analyzer, Thermo Flash EA 1112); particle size distribution (by laser scattering analyzer, with Beckman-Coulter LS-230); total organic carbon/total inorganic carbon in solutions or solids.
4. The lab has expertise and equipment for determining soil lipids (phospholipid fatty acids, or total soil fatty acids) and soil amino sugars, by extraction and derivatization followed by gas chromatography with flame ionization detection (Agilent 6890 GC with MIDI-Sherlock software for lipid identification).
5. Greenhouse gas analysis (GHGs) of field-collected samples, by gas chromatographic analysis (Agilent 7890 GC with infrared, flame ionization and electron capture detectors) of air samples in 5 mL exetainers.

Training and teaching is available to UW-Madison students and staff, as well as guest researchers in the following areas:

• Sample preparation for stable isotope and elemental analysis, as well as access to equipment for doing so (grinding equipment and microbalances). Advanced users may be trained to operate the elemental analyzer
• Operation of the particle size analyzer (50 sample minimum)
• Sample collection, storage and preparation for PLFA or amino sugar analysis
• Designing experiments for and working with the Microbiotron

Contacts:

For use of the Microbiotron, contact Dr. Thea Whitman (twhitman@wisc.edu; (608) 263-4947)

For stable isotope analysis of solids, particle size analysis, soil PLFA or soil amino sugar analysis, contact Dr. Harry Read (hwread@wisc.edu; (608) 265-4848)

For elemental analysis (carbon and nitrogen), particle size analysis, greenhouse gases or total organic carbon/total inorganic carbon, contact Erin Pierce (eapierce3@wisc.edu)