Sommerkorn et al.: Carbon Dioxide and Methane Emmissions at Arctic Tundra Sites
349
Methane emission rates from wet arctic tundra range - reported in the actual literature -
between 0.12-5.9 mg CH4 *m- 2 *h- 1 (summarized in Vourlitis and Oechel, 1997). The
presented methane emission rates are similar. The mean carbon loss by methane from the
polygon area is about 1.6 mg C *m- 2 *h- 1 during the summer period. This represents for only
4% of the total gaseous carbon loss from the polygon area to the atmosphere, which adds to
about 38.9 mg C*m- 2 *h- 1 (C02 and CH4). Nevertheless, this relative small quota of methane
is important with regard to the predicted global warming, for the efficiancy of methane for the
retention of longwave radiation is about 27 times higher than that of carbon dioxide (Lelieveld
et a!., 1993).
Whilst the dependence of methane emissions on the watertable position was shown in
numerous studies, the role of soil temperature is less clear (Svensson and Rosswall, 1984;
Moore and Knowles, 1989; Whalen et aI., 1991; Whalen and Reeburgh, 1992; Harriss et aI.,
1993). In this study the methane emissions revealed a primary dependency on the water table
position, in contrast to the CO2-emissions (Figure. 3a, 3b). The decrease of methane emissions
at the dry apex sites could be explained by the oxidation of methane in the dryer and well
aerated upper part of the active layer. The production rates and methane contents in pore water
are about the same in the deeper apex horizons as in the deeper horizons of the polygon
depressions (compare Samarkin et aI., 1997, same volume).
Beside watertable and soil temperature, other parameters like thickness of active layer,
structure of vegetation cover, as well as microbial characteristics can influence the methane
emissions from arctic soils (Morrissey and Livingstone, 1992; Chanton et aI., 1992; Topp and
Pattey, 1997; Vourlitis and Oechel, 1997)
Variations in microrelief lead to strong variations in methane emission rates. Therefore,
measurements of methane emission rates at only one single site are insufficient, complementary
mapping of soils and microrelief, a large number of measurements at different sites as done
during our campaign at Levinson Lessing Lake and a mobile, light weight equipment are
necessary for reliable flux data. In the next step the methane flux measurements will be
combined with stable carbon isotope investigations and studies of soil organic matter quality.
Acknowledgements
The authors wish to thank V. Samarkin for cooperation in the field and valuable discussion.
This study was financed by the German Ministry of Education, Science, Research and
Technology (BMBF grant 03PL014B).
References
Aleksandrova, V.D. (1980) The Arctic and Antarctic: Their devision into geobotanical areas. Cambridge
University Press, Cambridge, 247 pp.
Aselman, 1. and PJ. Crutzen (1989) Global distribution of natural freshwater wetlands and rice paddies, their net
primary productivity, seasonality and possible methane emissions. J.Atmos. Chern. 8, 307-358.
Billings, W.O., K.M. Peterson, J.O. Luken, and D.A. Mortensen (1984) Interaction of increasing atmospheric
carbon dioxide and soil nitrogen on the carbon balance of tundra microcosms. Oecologia 65, 26-29.
Botch, M.S., K.I. Kobak, T.S. Vinson, T.P. KoIchugina (1995) Carbon pools and accumulation in peatlands of
the former Soviet Union. Global Biogeochemical Cycles 9, 37-46.
Bunnel, F.L., S.F. MacLean Jf. and J. Brown (1975) Barrow, Alaska, U.S.A .. In: Rosswall, T. and O.W. Heal
(eds.), Structure and function of tundra ecosystems, Ecological Bulletins 20. Stockholm: Swedish Natural
Science Research Council, 425-448.
Chanton, J.P., C.S. Martens, c.A. Kelley, P.M. Crill and WJ. Showers (1992) Methane transport mechanisms
and isotopic fractionation in emergent macrophytes of an Alaskan tundra lakeJ. Geophys.Res. 97, 1668116688.
349
Methane emission rates from wet arctic tundra range - reported in the actual literature -
between 0.12-5.9 mg CH4 *m- 2 *h- 1 (summarized in Vourlitis and Oechel, 1997). The
presented methane emission rates are similar. The mean carbon loss by methane from the
polygon area is about 1.6 mg C *m- 2 *h- 1 during the summer period. This represents for only
4% of the total gaseous carbon loss from the polygon area to the atmosphere, which adds to
about 38.9 mg C*m- 2 *h- 1 (C02 and CH4). Nevertheless, this relative small quota of methane
is important with regard to the predicted global warming, for the efficiancy of methane for the
retention of longwave radiation is about 27 times higher than that of carbon dioxide (Lelieveld
et a!., 1993).
Whilst the dependence of methane emissions on the watertable position was shown in
numerous studies, the role of soil temperature is less clear (Svensson and Rosswall, 1984;
Moore and Knowles, 1989; Whalen et aI., 1991; Whalen and Reeburgh, 1992; Harriss et aI.,
1993). In this study the methane emissions revealed a primary dependency on the water table
position, in contrast to the CO2-emissions (Figure. 3a, 3b). The decrease of methane emissions
at the dry apex sites could be explained by the oxidation of methane in the dryer and well
aerated upper part of the active layer. The production rates and methane contents in pore water
are about the same in the deeper apex horizons as in the deeper horizons of the polygon
depressions (compare Samarkin et aI., 1997, same volume).
Beside watertable and soil temperature, other parameters like thickness of active layer,
structure of vegetation cover, as well as microbial characteristics can influence the methane
emissions from arctic soils (Morrissey and Livingstone, 1992; Chanton et aI., 1992; Topp and
Pattey, 1997; Vourlitis and Oechel, 1997)
Variations in microrelief lead to strong variations in methane emission rates. Therefore,
measurements of methane emission rates at only one single site are insufficient, complementary
mapping of soils and microrelief, a large number of measurements at different sites as done
during our campaign at Levinson Lessing Lake and a mobile, light weight equipment are
necessary for reliable flux data. In the next step the methane flux measurements will be
combined with stable carbon isotope investigations and studies of soil organic matter quality.
Acknowledgements
The authors wish to thank V. Samarkin for cooperation in the field and valuable discussion.
This study was financed by the German Ministry of Education, Science, Research and
Technology (BMBF grant 03PL014B).
References
Aleksandrova, V.D. (1980) The Arctic and Antarctic: Their devision into geobotanical areas. Cambridge
University Press, Cambridge, 247 pp.
Aselman, 1. and PJ. Crutzen (1989) Global distribution of natural freshwater wetlands and rice paddies, their net
primary productivity, seasonality and possible methane emissions. J.Atmos. Chern. 8, 307-358.
Billings, W.O., K.M. Peterson, J.O. Luken, and D.A. Mortensen (1984) Interaction of increasing atmospheric
carbon dioxide and soil nitrogen on the carbon balance of tundra microcosms. Oecologia 65, 26-29.
Botch, M.S., K.I. Kobak, T.S. Vinson, T.P. KoIchugina (1995) Carbon pools and accumulation in peatlands of
the former Soviet Union. Global Biogeochemical Cycles 9, 37-46.
Bunnel, F.L., S.F. MacLean Jf. and J. Brown (1975) Barrow, Alaska, U.S.A .. In: Rosswall, T. and O.W. Heal
(eds.), Structure and function of tundra ecosystems, Ecological Bulletins 20. Stockholm: Swedish Natural
Science Research Council, 425-448.
Chanton, J.P., C.S. Martens, c.A. Kelley, P.M. Crill and WJ. Showers (1992) Methane transport mechanisms
and isotopic fractionation in emergent macrophytes of an Alaskan tundra lakeJ. Geophys.Res. 97, 1668116688.