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 (=0)Isotope Standard

2H/1H V-SMOW18O/16O V-SMOW13C/12C V-PDB15N/14N Atmospheric air34S/32S V-CDT44Ca/40Ca seawater

87Sr/86Sr seawater

56Fe/54Fe average of 46 igneous rocks

Light Stable Isotope Abundances

Element Isotope Abundance

(%)

Terrestrial

Range

Hydrogen 1H2H (D)

99.985 ± 0.001

0.015 ± 0.001

700 ‰

Carbon 12C13C

98.89 ± 0.01

1.11 ± 0.01

100 ‰

Nitrogen 14N15N

99.634 ± 0.020

0.366 ± 0.020

50 ‰

Oxygen 16O17O18O

99.762 ± 0.016

0.038 ± 0.001

0.200 ± 0.014

100 ‰

NOTE: All labs do not provide the same QA/QC!NIST 1575 Pine run by 15 different labs

Source: Jeff Owen, 2004

13C 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)

… because

When stomates relatively closed, ci low and Δ approaches 4.4 ‰;

if wide open, Δ 27‰

source unknown (oops)a

i

c

caba *)( −+=Δ

Part 3: Advances in technology

TDL MC-ICP-MS (for iron) SIP (DNA studies) SIMS NMR PLFA (microbial)

Cz = Ca – Cb

Czz = Caa – Cbb

Czz = Caa – [(Ca-Cz)*b]

Czz = Caa – Cab + Cz b

Czz = Ca(a – b) + Czb

Czz – Czb = Ca(a – b)

Cz(z – b) = Ca(a – b)

z – b = [Ca(a – b) ]/Cz

z = b + [Ca(a – b) ]/Cz

The math for a Keeling plot

A linear relationship; the intercept is the isotopic composition of the “source”

A Keeling plot integrates spatially

Tu & Dawson, 2004

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)

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)

TDL used in an Eddy Covariance System

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

Principles of SIMS

Depth Profile of δ13C through an AOM Aggregate

Orphan et al. (2001) Science 293:484.

13C-PLFA: who is eating what

C (oxalate)

Fungal Gram + Gram - Actino0.00

0.05

0.10

0.15

0.20

0.25

DWCONI

A (glucose)

Relative Substrate Incorporation (Mol %)

0.0

0.2

0.4

0.6

0.8

1.0DWCONI

D (phenol)

Fungal Gram + Gram - Actino

*

Microbia l Group

B (glutamate)

*

**

**

Brant et al. 2006 SBB