Carbon and hydrogen isotopic characterization of methane from wetlands and lakes of the Yukon-Kuskokwim Delta, western Alaska

• Main Authors: Martens, C.S., Kelley, C.A., Chanton, J.P., Showers, W.J.
• Other Authors: College of Arts and Sciences, Department of Marine Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 1992
• Subjects: wetland; Alaska; isotope characterisation; tundra; methane; Yukon-Kuskokwim Delta; hydrogen; lake; USA; carbon; Yukon; Kuskokwim; Tundra
• Online Access: https://doi.org/10.17615/dtff-dd02; https://cdr.lib.unc.edu/downloads/z603r715n?file=thumbnail; https://cdr.lib.unc.edu/downloads/z603r715n

The total methane flux to the troposphere from tundra environments of the Yukon-Kuskokwim Delta is dominated by emissions from wet meadow tundra (~75%) and small, organic-rich lakes (~20%). The mean δ13C value of methane diffusing into collar-mounted flux chambers from wet meadow environments near Bethel, Alaska, was -65.82±2.21‰ (±1 sigma, n=18) for the period July 10 to August 10, 1988. A minimum ebullition estimated for the 5% of total Delta area comprised of small lakes ranges from 0.34 to 9.7 × 1010g Ch4yr-1, which represents 0.6% to 17% of the total Delta methane emission. The δ13C and δD values of this ebullitive flux are -61.41±2.46‰ (n=38) and -341.8±18.2‰ (n=21), respectively. The methane in gas bubbles from two lakes is of modern, bomb carbon enriched, radiocarbon age. Gas bubble δ13C values varied from 2 to 5‰ seasonally, reaching heaviest values in midsummer; no such variations in δD values were observed.