Carbon cycle as reflected in atmospheric CO2 in the western US


The carbon isotope ratios of atmospheric CO2 reflect a balance between source (respiration, anthropogenic activities, fires) and sink (photosynthesis) processes. As turbulence dominates the mixing of CO2 in the atmosphere, the distribution of [CO2] values within and above the convective boundary have been used for scaling carbon cycle activities. Here stable isotopes play a role constraining interpretations on the role of fluxes at large scales. Typically, Keeling-plots are used to characterize terrestrial fluxes. The utility of carbon isotopes in CO2 is to constrain interpretations of what is driving changes in biosphere-atmosphere CO2 estimates (net ecosystem exchange, NEE). Increasingly, atmospheric models (e.g., WRFF, STILT) can be combined with concentrations and carbon isotopes in CO2 to make predictions of fluxes and to dissect out the sources contributing to these fluxes.

The project will support a postdoc to compile and synthesize the data from published Keeling plot studies and local to global-scale monitoring networks to elaborate the role of isotopic data in describing CO2 flux attribution and ecosystem-level gas exchange over multiple spatial scales. Data anlaysis will involve significant quantitative work with a number of ecosystem, atmospheric, and chemical transport models.

Several initial projects are anticipated:

  • First, what are the relative contributions of C3 and C4 photosynthesis to gross primary productivity in grasslands, forests, and other dominant ecosystems across North America?
  • Second, what is the role of the anthropogenic signal in modifying atmospheric concentrations and carbon isotopes in CO2?
  • Third, how can concentrations and carbon isotopes in CO2 be used to study urban metabolism in cities across North America?
  • Fourth, what are the relative roles and variation of different human and non-human emissions sources on the CO2 emission budgets for urban ecosystems?

Affiliated faculty

Bowling, Ehleringer, Gurney, Pataki, Randerson, Wofsy

Image courtesy of the Institute of Arctic and Alpine Research, University of Colorado, and NOAA Global Monitoring Division

ITCE News!

New Instructional Video Module on Biogeography and Isotope Fractionation in C3 & C4 plants with Christopher Still! Check out all of the videos at the bottom of the 'Summer Courses' tab!


New Publications - Two new papers by SPATIAL alum Sean Brennan involving salmon migration (here) and using dendritic network models to improve Strontium isoscapes (here)!


New Blog Post - Former SPATIAL student Katie Wedemeyer-Strombel discusses her experience as a SPATIAL student last summer! (Check it out here!)


Awards - Former ITCE post-doc Jennifer Cotton has received an NSF Macrosystems Biology Grant. Congratulations, Jen! (Check out the NEON press release here!)

New Publications - Former SPATIAL student Chabi Djagoun's work on carbon isotope niches in herbivores in a west African savannah is now available in Mammalian Biology - Free download until Nov 7th! (Check it out here)


New Publications - Former SPATIAL student Giovanny Mosquera in two new publications involving high elevation tropical ecosystems (Hydrological Processes and Hydrology and Earth System Sciences)


Awards - Congratulations to Jim Ehleringer for receiving the prestigious Rosenblatt Prize for Excellenc! (Read more here.)


Presentations - Several SPATIAL & IsoCamp instructors and past students represented at the 10th annual (ISOECOL meeting in Tokyo!) last week.

Archived ITCE News


IsoMAP: WebGIS for Isotopes

IsoMAP is a dynamic, online workspace for spatial analysis, modeling and prediction of stable isotope ratio variation in the natural environment. The initial realease of the IsoMAP gateway is now live and supports precipitation isotope ratio modeling. Visit IsoMAP to learn more or to start making isoscapes today!