336
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
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- - - - - - - - - - . permafrost-boun ~ary - - - - - - - - - - - -
I
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o 1 2 3 4 5 6 7 8 9 10 11 12
methane concentration [mg CH/1000 cm- 3 pore water]
Figure 3a: Methane concentrations in soil pore water, polygon depression, August 1996,
..... :'lrcJ, l\urllJst
_. 22r\(j AUGJust
during that period (compare Sommerkorn et ai, this volume). Svensson and Rosswall (1984)
found 5.5% of total gaseous loss from wet, not always waterlogged areas to the atmosphere
were methane.
The presented methane emission rates fall into the range of results from other investigations:
wet, subarctic and arctic tundra north of 60 0 N have mean daily emission rates between 0-600
mg CH 4 *d- 1*m-2 . The most of the reported emisssion rates are between 10-150 mg CH 4 *d1*m-2 (Bartlett et ai, 1992; Harriss et ai, 1993; Inoue et aI., 1995; Morrissey and Livingstone,
1992; Nakayama, 1995 a,b; Rivkina et aI., 1993; Samarkin et aI., 1994; Sebacher et aI., 1986;
Svensson and Rosswall, 1984; Whalen et aI., 1991; Whalen and Reeburgh, 1988, 1990,
1992).
Methane production and consumption
The methane concentrations in pore water are presented in Figures 3a and b. The methane store
in the 30 cm thick active layer of the polygon depression part of the patterned ground,
calculated using data from methane concentrations in pore waters and taking into account the
different water contents of the soil horizons (50-90 w/w%, mean 60 w/w%), is about 1070 mg
CH 4 *m-2 at the beginning of August, and 390 mg CH 4 *m- 2 at the end of August. The methane
store decreased from 3th to 22th August on 680 mg CH 4 *m- 2 or 36 mg CH 4 *d- h m- 2 . This
value - received by calculation - is lower than the mean methane flux measured by chamber in
this period.
The amount of stored methane in pore water was high at the end of July and decreased over
the time. It was exhausted at the end of August. explanations for this observation may be
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
o
10
E
~
.r:
- 0- m
"20
30
I
I
I, ..
I
I
'1
I
- -
_I
I
I
-- I
I
1
I
I
- - - - - - - - - - . permafrost-boun ~ary - - - - - - - - - - - -
I
I
I
I
I
I
o 1 2 3 4 5 6 7 8 9 10 11 12
methane concentration [mg CH/1000 cm- 3 pore water]
Figure 3a: Methane concentrations in soil pore water, polygon depression, August 1996,
..... :'lrcJ, l\urllJst
_. 22r\(j AUGJust
during that period (compare Sommerkorn et ai, this volume). Svensson and Rosswall (1984)
found 5.5% of total gaseous loss from wet, not always waterlogged areas to the atmosphere
were methane.
The presented methane emission rates fall into the range of results from other investigations:
wet, subarctic and arctic tundra north of 60 0 N have mean daily emission rates between 0-600
mg CH 4 *d- 1*m-2 . The most of the reported emisssion rates are between 10-150 mg CH 4 *d1*m-2 (Bartlett et ai, 1992; Harriss et ai, 1993; Inoue et aI., 1995; Morrissey and Livingstone,
1992; Nakayama, 1995 a,b; Rivkina et aI., 1993; Samarkin et aI., 1994; Sebacher et aI., 1986;
Svensson and Rosswall, 1984; Whalen et aI., 1991; Whalen and Reeburgh, 1988, 1990,
1992).
Methane production and consumption
The methane concentrations in pore water are presented in Figures 3a and b. The methane store
in the 30 cm thick active layer of the polygon depression part of the patterned ground,
calculated using data from methane concentrations in pore waters and taking into account the
different water contents of the soil horizons (50-90 w/w%, mean 60 w/w%), is about 1070 mg
CH 4 *m-2 at the beginning of August, and 390 mg CH 4 *m- 2 at the end of August. The methane
store decreased from 3th to 22th August on 680 mg CH 4 *m- 2 or 36 mg CH 4 *d- h m- 2 . This
value - received by calculation - is lower than the mean methane flux measured by chamber in
this period.
The amount of stored methane in pore water was high at the end of July and decreased over
the time. It was exhausted at the end of August. explanations for this observation may be