1 / 34

William H. Schlesinger Nicholas School of the Environment and Earth Sciences Duke University

The Global Carbon Cycle and the Duke Forest Free-Air CO 2 Enrichment (FACE) Project. William H. Schlesinger Nicholas School of the Environment and Earth Sciences Duke University. Photosynthesis CO 2 + H 2 O CH 2 O + O 2. Nitrogen Budget: Ambient and Elevated CO 2

taudrey
Download Presentation

William H. Schlesinger Nicholas School of the Environment and Earth Sciences Duke University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Global Carbon Cycle and the Duke Forest Free-Air CO2 Enrichment (FACE) Project William H. Schlesinger Nicholas School of the Environment and Earth Sciences Duke University

  2. Photosynthesis CO2 + H2O CH2O + O2

  3. Nitrogen Budget: Ambient and Elevated CO2 Component Ambient Elevated %Change (kg/ha/yr) (kg/ha/yr) __________________________________________________________ Plant Requirement 51.9 61.5 18.5 Retranslocation 28.6 31.5 10.2 Uptake from Soil 23.3 30.0 28.9 __________________________________________________________ Nitrogen-Use Efficiency 292 311 6.6 (NPP/Requirement) __________________________________________________________ (Finzi et. al. 2002)

  4. Chemical Weathering by Carbonation CO2 + H2O H+ + HCO3- H2CO3 2NaAlSi3O8 + 2H2CO3 + 9H2O 2Na+ + 2HCO3- + 4H4SiO4 + Al2Si2O5(OH)4

  5. Soil Solution Chemistry (meq/liter) Depth Ambient Elevated Cl 15 cm 0.04 0.05 200 cm 0.10 0.17 Cations 15 cm 0.36 0.41 200cm 0.76 2.82 HCO3 –Alkalinity 15cm 0.13 0.13 200cm 0.64 1.68 Dissolved Silicon 15cm 0.07 0.08 200cm 0.28 0.35

  6. Estimated Groundwater Sink in 2050 Groundwater Flux (Zekster and Loaiciga 1993) 1 x 1016 liters/year HCO3 Concentration at 200 cm Ambient 3 mM = 0.40 x 1015 gC/yr Elevated 4 mM = 0.52 x 1015 gC/yr Net Sink of 5 gC/m2/yr or 0.12 x 1015gC/yr worldwide

  7. Carbon Sequestration Due to Growth at High CO2 (gC/m2/yr) ______________________________________________________ Control Elevated Change “Beta Factor” Stem Biomass 397 505 108 **27% Forest Floor 78 130 52 ** 67% Soil Organic Matter 0-15 cm 72 99 27 ns 38% 15-30 cm 21 34 13 ns 62% Groundwater Flux 16 21 5 ** 31% ______________________________________________________ Total 584 789 205 35%

  8. Crude, upper-limit estimate of forest uptake by atmospheric CO2 in 2050 Global NPP in Forests 26.9 x 1015 gC/yr (Field et al. 1998) Response to FACE in +20% = 5.6 x 1015 gC/yr globally …Duke Forest IPCC BAU Emissions 15 x 1015 gC/yr …Estimate for 2050 Gross Increment of carbon 36% …Uptake by Forests _____________________________________________________________

More Related