Methane flux from northern peatlands

• Published in: Nature (London) 1985-01, Vol.315 (6021), p.652-654
• Main Authors: Harriss, Robert C, Gorham, Eville, Sebacher, Daniel I, Bartlett, Karen B, Flebbe, Patricia A
• Format: Article
• Language: English
• Subjects: Chemical composition and interactions. Ionic interactions and processes; Earth, ocean, space; Exact sciences and technology; External geophysics; Freshwater; Humanities and Social Sciences; letter; Meteorology; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/315652a0

The concentration of methane (CH 4 ) in the global troposphere is increasing. Ambient air measurements document an approximate rate of increase of 1–2% yr −1 over the past decade 1–4 . Measurements of CH 4 in air bubbles trapped in polar ice indicate that tropospheric concentrations of CH 4 several hundred years ago may have been ∼45% of present levels 5–7 . To understand and assess possible causes of the atmospheric CH 4 increase requires improved quantitative knowledge of global sources and sinks of CH 4 . Previous attempts to estimate sources of atmospheric CH 4 , based on very few measurements, have suggested that natural and agricultural wetlands are major sources 8,9 . The major wetland regions of the world are in boreal, low Arctic and tropical ecosystems 10 . It is these regions, particularly in peatland habitats where major accumulations of organic materials occur under anaerobic conditions, that should be significant sources of global tropospheric CH 4 . The most extensive peatlands in the world occur in the boreal taiga zone between ∼45° and 65° N latitude. More than 95% of world peat resources occur in the Soviet Union, Canada, the United States, Sweden, Norway, Finland and the United Kingdom 10 . We report here the first survey of CH 4 flux from northern peatlands of the United States. Emission rates ranged from 0.003 to 1.94 g CH 4 m −2 day −1 , with half of these values between 0.1 and 0.4 g CH 4 m −2 day −1 . The frequency distribution is log normal (Fig. 1) and the mean emission rate is 0.337 g CH 4 m −2 day −1 . Such fluxes are higher than most values reported for other ecosystems, suggesting that northern peatlands may be an important source of global tropospheric CH 4 .