Laboratory and analytical facilities

Our laboratory facilities provide us the means to physically, chemically and biologically characterize soils from a wide range of ecosystems. We are particularly interested in characterizing the organic matter in these soils to assess its quantity, quality and dynamics.

All materials change their physical properties and their chemical characteristics as a function of temperature. Our simultaneous thermal analyzers (i.e., thermogravimetry and differential scanning calorimetry) provide the capability of measuring mass changes, decomposition behavior, thermal stability, oxidation behavior, etc. of various organic and mineral materials by subjecting samples to temperatures up to 1200°C. The lab houses two analyzers: a Netzsch STA409PC Luxx system for running single samples, and a newer Netzsch STA449 F5 Jupiter that has an automatic sample carrier with a capacity of 18 samples. Both instruments are coupled to LICOR LI-840a infrared gas analyzers (IRGAs) for measuring CO2 and H20 in the evolved gas during ramped combustion. Our primary interest is the thermal stability of organic matter in soil and sediment samples as as a proxy for biogeochemical stability (ie, resistance to microbial decomposition in the environment) and as means of describing of quality continuum of soil organic matter. We are also able to distinguish soil organic matter (neogenic carbon) from pyrogenic carbon (char), geogenic carbon (coal) and inroganic carbon (carbonates).

A LICOR LI-7000 infra-red gas analyzer (IRGA) provides the capability for high-precision measurements of CO2 concentrations in gas samples from ambient levels up to 50,000 ppm (depending on injection volume). A refrigerator-sized incubator used for laboratory soil incubations at constant-temperature. This capability is used to quantify soil respiration during laboratory incubation experiments as a measure of soil organic matter decomposition by the soil microbial population and its enzymes. An EGM-4 and SRC-1 instrument from PP Systems also provides the same capability for CO2 efflux measurements in the field.

We can measure pH in solutions and soil pastes using our pH meter, and dissolved organic carbon (DOC) and a large number of dissolved nutrients (N, P, etc.) or trace elements (Fe, Cl, etc.) from environmental water samples or soil extracts using our HACH UV-Vis spectrophotometer.

Our laboratory is well equipped to provide excellent facilities for research in soil organic biogeochemistry. These laboratory facilities include: an ultrasonic generator and disruptor horn (Branson Sonifier 450D) for physical dispersion of strongly aggregated soil samples, and a high-speed centrifuge (Beckman J2-MI) with high-volume swinging bucket and fixed angle rotors for separation and isolation of soil particle size (silt and clay) and density fractions, and orbital and horizontal shakers to perform the dispersions and extractions.

In addition to our own lab, shared department laboratory space houses a range of traditional soil preparation equipment such as sieves, balances, shakers, grinders, soil and plant drying ovens, muffle furnaces, and USDA certified storage space for quarantined soil samples. Departmental facilities also house a range of instrumentation, including: laser diffractometry for particle size analysis, total C and N elemental analyzers (Costech Instruments Elemental Combustion System), stable isotope ratio mass spectrometry (Thermo Finnigan Delta Plus) with various sample preparation units for analysis of 13C, 15N and 18O, mineralogical analysis by x-ray diffraction (XRD) and BET specific surface analyzer, and elemental analysis by inductively coupled plasma analysis (ICP-OES), ion chromatrography (IC) and advanced flame and graphite furnace atomic adsorption spectroscopy (AA) and portable and benchtop x-ray fluorescence (XRF) units.