Record Details
Field | Value |
---|---|
Title | Observations of ¹⁴CO₂ in ecosystem respiration from a temperate deciduous forest in Northern Wisconsin |
Names |
Phillips, Claire L.
(creator) McFarlane, Karis J. (creator) LaFranchi, Brian (creator) et al. (creator) |
Date Issued | 2015-04 (iso8601) |
Note | To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/jgr/journal/10.1002/%28ISSN%292169-8961/. |
Abstract | The ¹⁴CO₂ composition of plant and soil respiration can be used to determine the residence time of photosynthetically fixed carbon before it is released back to the atmosphere. To estimate the residence time of actively cycled carbon in a temperate forest, we employed two approaches for estimating the Δ¹⁴CO₂ of ecosystem respiration (Δ¹⁴C-R[subscript eco]) at the Willow Creek AmeriFlux site in Northern Wisconsin, USA. Our first approach was to construct nighttime Keeling plots from subcanopy profiles of Δ¹⁴CO₂ and CO₂, providing estimates of Δ¹⁴C-R[subscript eco] of 121.7‰ in June and 42.0‰ in August 2012. These measurements are likely dominated by soil fluxes due to proximity to the ground level. Our second approach utilized samples taken over 20 months within the forest canopy and from 396 m above ground level at the nearby LEF NOAA tall tower site (Park Falls, WI). In this canopy-minus-background approach we employed a mixing model described by Miller and Tans (2003) for estimating isotopic sources by subtracting time-varying background conditions. For the period from May 2011 to December 2012 the estimated Δ¹⁴C-R[subscript eco] using the Miller-Tans model was 76.8‰. Together, these Δ¹⁴C-R[subscript eco] values represent mean R[subscript eco] carbon ages of approximately 1–19 years. We also found that heterotrophic soil-respired Δ¹⁴C at Willow Creek was 5–38‰ higher (i.e., 1–10 years older) than predicted by the Carnegie-Ames-Stanford Approach global biosphere carbon model for the 1 × 1 pixel nearest to the site. This study provides much needed observational constraints of ecosystem carbon residence times, which are a major source of uncertainty in terrestrial carbon cycle models. |
Genre | Article |
Topic | radiocarbon |
Identifier | Phillips, C. L., McFarlane, K. J., LaFranchi, B., & Lehman, S. J. (2015). Observations of ¹⁴CO₂ in ecosystem respiration from a temperate deciduous forest in Northern Wisconsin. Journal of Geophysical Research: Biogeosciences, 120(4), 600-616. doi:10.1002/2014JG002808 |