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Effects of raised CO 2 on potential CH 4 production and oxidation in, and CH 4 emission from, a boreal mire
Author(s) -
Saarnio Sanna,
Alm Jukka,
Martikainen Pertti J.,
Silvola Jouko
Publication year - 1998
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1046/j.1365-2745.1998.00248.x
Subject(s) - sphagnum , mire , peat , bog , moss , boreal , ombrotrophic , environmental chemistry , chemistry , taiga , botany , environmental science , ecology , biology
1 In a glasshouse experiment we studied the effect of raised CO 2 concentration (720 p.p.m.) on CH 4 emission at natural boreal peat temperatures using intact cores of boreal peat with living vascular plants and Sphagnum mosses. After the end of the growing season half of the cores were kept unnaturally warm (17–20 °C). The potential for CH 4 production and oxidation was measured at the end of the emission experiment. 2 The vascular cores (‘Sedge’) consisted of a moss layer with sedges, and the moss cores (‘ Sphagnum ’) of Sphagnum mosses (some sedge seedlings were removed by cutting). Methane efflux was 6–12 times higher from the Sedge cores than from the Sphagnum cores. The release of CH 4 from Sedge cores increased with increasing temperature of the peat and decreased with decreasing temperature. Methane efflux from Sphagnum cores was quite stable independent of the peat temperatures. 3 In both Sedge and Sphagnum samples, CO 2 treatment doubled the potential CH 4 production but had no effect on the potential CH 4 oxidation. A raised concentration of CO 2 increased CH 4 efflux weakly and only at the highest peat temperatures (17–20 °C). 4 The results suggest that in cool regions, such as boreal wetlands, temperature would restrict decomposition of the extra substrates probably derived from enhanced primary production of mire vegetation under raised CO 2 concentrations, and would thus retard any consequent increase in CH 4 emission.