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FOR NOTES / ADDITIONAL MATERIAL not to be covered in 40 min

FOR NOTES / ADDITIONAL MATERIAL not to be covered in 40 min. Stable Isotope Standards ( d =0). Light Stable Isotope Abundances. NOTE: All labs do not provide the same QA/QC! NIST 1575 Pine run by 15 different labs. Source: Jeff Owen, 2004. d 13 C values of plants are affected by / reflect:.

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FOR NOTES / ADDITIONAL MATERIAL not to be covered in 40 min

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  1. FOR NOTES / ADDITIONAL MATERIAL not to be covered in 40 min

  2. Stable Isotope Standards (d=0)

  3. Light Stable Isotope Abundances

  4. NOTE: All labs do not provide the same QA/QC! NIST 1575 Pine run by 15 different labs Source: Jeff Owen, 2004

  5. d13C values of plants are affected by / reflect: • moisture stress (e.g., Rundel and Sharifi, 1993, Stewart et al. 1995) • salinty (e.g., Guy et al. 1980) • light level (e.g., Ehleringer et al. 1986) • height in the canopy (e.g., Leavitt and Long 1982, McDowell et al. 2005) • lifespan (e.g., Ehleringer et al. 1993)

  6. … because • When stomates relatively closed, ci low and Δ approaches 4.4 ‰; • if wide open, Δ  27‰ source unknown (oops)

  7. Part 3: Advances in technology • TDL • MC-ICP-MS (for iron) • SIP (DNA studies) • SIMS • NMR • PLFA (microbial)

  8. The math for a Keeling plot Cz = Ca – Cb Czdz = Cada – Cbdb Czdz = Cada – [(Ca-Cz)*db] Czdz = Cada – Cadb + Cz db Czdz = Ca(da – db) + Czdb Czdz – Czdb = Ca(da – db) Cz(dz – db) = Ca(da – db) dz – db = [Ca(da – db) ]/Cz dz = db + [Ca(da – db) ]/Cz A linear relationship; the intercept is the isotopic composition of the “source”

  9. A Keeling plot integrates spatially Tu & Dawson, 2004

  10. TDLAS = Tunable Diode Laser Absorption Spectroscopy A laser based system for measuring the mole fraction of a specific gas molecule Raw materials: Lead, Selenium, Sulfur End Product: About the size of a pencil eraser! Bowling et al. (2003)

  11. Tunable diode laser absorption spectroscopy • fast-response analyzer for carbon isotopes of CO2 • very narrow wavelength infrared absorption • 4.3594 (12CO2) and 4.3582 mm (13CO2) • 1 kW and liquid nitrogen required • operates at field site Bowling et al. (2003)

  12. TDL used in an Eddy Covariance System

  13. SIP: Principle • Add a 13C-labeled compound (15N, 2H) • Incubate • Extract and separate an informative biomolecule • Lipids (PLFA) • Nucleic acids (DNA or RNA) • Proteins (not yet used) • Analyze biomolecule

  14. Principles of SIMS

  15. Depth Profile of δ13C through an AOM Aggregate Orphan et al. (2001) Science 293:484.

  16. 13C-PLFA: who is eating what Brant et al. 2006 SBB

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