Saarnio S, Alm Jukka, Silvola Jouko, Lohila Annalea, Nykänen Hannu, Martikainen Pertti J
Department of Biology, University of Joensuu, P.O.Box 111, FIN-80101 Joensuu, Finland fax: +358 13 2513590; e-mail:
Laboratory of Environmental Microbiology, National Public Health Institute, P.O.Box 95, FIN-70701 Kuopio, Finland, , , , , , FI.
Oecologia. 1997 Apr;110(3):414-422. doi: 10.1007/s004420050176.
Temporal and spatial variation in CH emissions was studied at hummock, Eriophorum lawn, flark and Carex lawn microsites in an oligotrophic pine fen over the growing season using a static chamber method, and CH production and oxidation potentials in peat profiles from hummock and flark were determined in laboratory incubation experiments. Emissions were lowest in the hummocks, and decreased with increasing hummock height, while in the lawns and flarks they increased with increasing sedge cover. Statistical response functions with water table and peat temperature as independent variables were calculated in order to reconstruct seasonal CH emissions by reference to the time series for peat temperature and water table specific to each microsite type. Mean CH emissions in the whole area in the snow-free period of 1993, weighted in terms of the proportions of the microsites, were 1.7 mol CH m. Potential CH production and oxidation rates were very low in the hummocks rising above the groundwater table, but were relatively similar when expressed per dry weight of peat both in the hummocks and flarks below the water table. The CH production potential increased in autumn at both microsites and CH oxidation potential seemed to decrease. The decrease in temperature in autumn certainly reduced in situ decomposition processes, possibly leaving unused substrates in the peat, which would explain the increase in CH production potential.
在生长季节，采用静态箱法研究了贫营养松泥炭地中丘状微生境、羊胡子草草坪、洼地和苔草草坪微生境中CH排放的时空变化，并通过实验室培养实验测定了丘状微生境和洼地泥炭剖面中的CH产生和氧化潜力。丘状微生境中的排放最低，且随丘状高度增加而降低，而在草坪和洼地中，排放随莎草覆盖率增加而增加。计算了以地下水位和泥炭温度为自变量的统计响应函数，以便参照每种微生境类型特有的泥炭温度和地下水位时间序列重建季节性CH排放。1993年无雪期整个区域的平均CH排放，按微生境比例加权后为1.7 mol CH m。高于地下水位的丘状微生境中潜在的CH产生和氧化速率非常低，但以泥炭干重表示时，地下水位以下的丘状微生境和洼地中的情况相对相似。秋季两个微生境中的CH产生潜力均增加，而CH氧化潜力似乎降低。秋季温度降低肯定减少了原位分解过程，可能使泥炭中留下未利用的底物，这可以解释CH产生潜力的增加。
