Objectives and Methods

For detailed information about the SIRFER Lab, Special Sessions, and Instrumentation, please see the 2008 Lab Manual.

Laboratory Objectives

The laboratory associated with the Stable Isotopes in Ecology Course will introduce participants to a number of methods and approaches used in stable isotope analysis. It will involve hands-on experience with sample collection, sample preparation, isotope analysis, and data interpretation.

The labs will be built around small projects mainly involving Red Butte Canyon, a protected watershed immediately adjacent to campus. The proximity of this site will allow us to collect field samples and do follow up work.

There will be a set of handouts for the lab efforts which describe the overall objectives, sampling design, analysis method, specific questions that should be answered and suggestions for what could be included in your presentations.

We will break into three working groups:
  • each group will consist of eight participants
  • each group will have a faculty participant to help develop ideas, coordinate activities, and provide training on different methods
  • each group will have its own technical help for instrument and method training
  • we will ensure that each group has a diverse composition initially, but individuals may switch among groups later
  • at occasional evening get-togethers throughout the course, 1-2 members from each group will present a brief summary of what that group learned with their group project
The broadly-defined project topics are (a) water and carbon and (b) ecosystem and atmosphere.

What to expect from your laboratory experience

By the end of this laboratory experience, participants will have had an opportunity to be exposed to (a) all relevant instrumentation and techniques listed below, (b) 3-5 different group projects (that will be presented at joint dinners), (c) 2-3 days of one-on-one discussion opportunities with each lecturer, and (d) opportunities to present and receive feedback on your specific research projects.

Methods and Techniques

Vacuum lines and parpation methods
  • in-tube sample combustion for C and/or N analysis
  • CN elemental analyzer combustion for C and/or N analysis
  • zinc reduction of water for deuterium analysis
  • offline separation of water and carbon dioxide in air or in a sealed sample
  • carbon dioxide equilibration with water for oxygen analysis
  • acidification of carbonate for carbon and oxygen analysis
  • cellulose preparation and nitration
  • GC analysis of CO2, N2O, and CH4 in air
  • building your own vacuum lines
Field techniques
  • atmospheric water vapor collection
  • leaf collection
  • stem collection for water sources
  • water collection
  • air sampling
  • soil respiration sampling
  • soil gas sampling
  • double-labeled water
  • breath sampling
Instrumentation
  • Delta S isotope ratio mass spectrometer
  • MAT 252 isotope ratio mass spectometer
  • Delta Plus isotope ratio mass spectrometer
  • continuous flow interface
  • dual inlet sample introduction
  • elemental analyzer
  • tube cracker
  • gas chromatography
  • laser/GC
  • precon
  • microbalance
  • soil respiration chamber and gas analysis system
  • infrared gas analyzer