CH4 and N2O emissions from a forest‐alas ecosystem in the permafrost taiga forest region, eastern Siberia, Russia
CH4 and N2O emissions from a forest‐alas ecosystem in the permafrost taiga forest region, eastern Siberia, Russia
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DOI：
10.1029/2007jg000521
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发表时间：
2008-06
影响因子：
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通讯作者：
F. Takakai;A. Desyatkin;C. Lopez;A. Fedorov;R. Desyatkin;R. Hatano
中科院分区：
文献类型：
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作者：
F. Takakai;A. Desyatkin;C. Lopez;A. Fedorov;R. Desyatkin;R. Hatano
[1]“阿拉斯”是东西伯利亚雅库特中部针叶林中的草原覆盖的成熟热岩溶洼地，是全新世早期热岩溶形成的产物。阿拉斯是雅库特中部低地重要的土地覆盖类型，占土地总面积的17%。在一个典型的人工湿地中，在两年的生长季中，对CH 4和N2 O通量进行了时间上的测量。7个监测样地代表了不同的植被类型：落叶松林（F），干草原（DG），四个潮湿的草地（WG）暂时或连续淹没，和池塘表面（P）淹没连续无植被。池塘洪水面积在融雪后达到最大值，夏季减少。F和DG地块是小的CH 4汇。湿地（包括WG和P）是较大的CH 4源（生长季节的累积值：17至864 kg CH 4-C ha−1），排放率随洪水条件的不同而变化很大。所有地块都是轻微的N2 O源或汇，除了WG地块（0.16至1.7 kg N2 O-N ha−1），在洪水结束后观察到峰值排放。各样地N2 O累积排放的全球变暖潜势（100年时间跨度）均低于各CH 4排放的全球变暖潜势。整个WG区域（7.93公顷）的CH 4排放量估计占整个Alas（28.9公顷）排放量的88%。目前雅库特中部的多年冻土-针叶林地区可能是一个CH 4的净排放源，因为存在着阿拉斯。
[1] ‘Alases’ are mature thermokarst depressions covered by grassland distributed in taiga forests in central Yakutia, eastern Siberia, following thermokarst formation initiated in early Holocene. Alases are important land-cover class in the central Yakutia lowland occupying 17% of the total land area. CH4 and N2O fluxes were measured temporally in a typical alas which have a pond at the center during the growing season of two years. Seven monitoring plots represented various vegetation types: a larch forest (F), a dry grassland (DG), four wet grasslands (WG) flooded temporarily or continuously, and a pond surface (P) flooded continuously without vegetation. The pond flooding area reached its maximum just after snow-melting and decreased during the summer. The F and DG plots were small CH4 sinks. The wet plots (including WG and P) were large CH4 sources (cumulative value of growing season: 17 to 864 kg CH4-C ha−1), and emission rates vary drastically depending on flooding conditions. All plots were slight sources or sinks of N2O except for the WG plots (0.16 to 1.7 kg N2O-N ha−1) where peak emissions were observed after the flooding ended. The global warming potentials (time horizon of 100 years) of the cumulative N2O emissions from the plots were lower than those of each CH4 emissions. Estimated total CH4 emission from the whole WG area (7.93 ha) accounted for 88% of the emission from the whole alas (28.9 ha). The current permafrost-taiga region in central Yakutia could be a net CH4 source owing to the presence of alases.