Carbon gas exchange at a southern Rocky Mountain wetland, 1996–1998


  • Kimberly P. Wickland,

  • Robert G. Striegl,

  • M. Alisa Mast,

  • David W. Clow


Carbon dioxide (CO2) and methane (CH4) exchange between the atmosphere and a subalpine wetland located in Rocky Mountain National Park, Colorado, at 3200 m elevation were measured during 1996–1998. Respiration, net CO2 flux, and CH4 flux were measured using the closed chamber method during snow-free periods and using gas diffusion calculations during snow-covered periods. The ranges of measured flux were 1.2-526 mmol CO2 m−2 d−1 (respiration), −1056−100 mmol CO2m−2 d−1 (net CO2exchange), and 0.1–36.8 mmol CH4m−2 d−1 (a positive value represents efflux to the atmosphere). Respiration and CH4 emission were significantly correlated with 5 cm soil temperature. Annual respiration and CH4 emission were modeled by applying the flux-temperature relationships to a continuous soil temperature record during 1996–1998. Gross photosynthesis was modeled using a hyperbolic equation relating gross photosynthesis, photon flux density, and soil temperature. Modeled annual flux estimates indicate that the wetland was a net source of carbon gas to the atmosphere each of the three years: 8.9 mol C m−2 yr−1 in 1996, 9.5 mol C m−2 yr−1 in 1997, and 9.6 mol C m−2 yr−1 in 1998. This contrasts with the long-term carbon accumulation of ∼0.7 mol m−2 yr−1 determined from 14C analyses of a peat core collected from the wetland.