What Drives Carbon Isotope Fractionation by the Terrestrial Biosphere?
During photosynthesis, terrestrial plants preferentially assimilate the lighter and much more abundant form of carbon, 12C, which accounts for roughly 99% of naturally occurring forms of this element. This photosynthetic preference for lighter carbon is driven principally by differences in molecular diffusion of carbon dioxide with differing 13C/12C across stomatal pores on leaves, followed by differences in carboxylation rates by the Rubisco enzyme that is central to the process of photosynthesis. As a result of these slight preferences, which work out to about a 2% difference in the fixation rates of 12CO2 versus 13CO2 by C3 vegetation, plant tissues are depleted in the heavier form of carbon (13C) relative to atmospheric CO2. More…
-- Christopher Still and Bharat Rastogi,
- Article Category
- Research Articles
Does vapor pressure deficit drive the seasonality of δ13C of the net land‐atmosphere CO2 exchange across the United States?
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Eos.org: Earth & Space Science News
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