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Methane emissions from an alpine wetland on the Tibetan Plateau: Neglected but vital contribution of the nongrowing season
Author(s) -
Song Weimin,
Wang Hao,
Wang Guangshuai,
Chen Litong,
Jin Zheg,
Zhuang Qianlai,
He JinSheng
Publication year - 2015
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2015jg003043
Subject(s) - environmental science , growing season , plateau (mathematics) , wetland , atmospheric sciences , methane , dry season , atmospheric methane , atmosphere (unit) , hydrology (agriculture) , seasonality , ecology , meteorology , geography , biology , geology , mathematical analysis , mathematics , geotechnical engineering
Abstract The vast wetlands on the Tibetan Plateau are expected to be an important natural source of methane (CH 4 ) to the atmosphere. The magnitude, patterns and environmental controls of CH 4 emissions on different timescales, especially during the nongrowing season, remain poorly understood, because of technical limitations and the harsh environments. We conducted the first study on year‐round CH 4 fluxes in an alpine wetland using the newly developed LI‐COR LI‐7700 open‐path gas analyzer. We found that the total annual CH 4 emissions were 26.4 and 33.8 g CH 4 m −2 in 2012 and 2013, respectively, and the nongrowing season CH 4 emissions accounted for 43.2–46.1% of the annual emissions, highlighting an indispensable contribution that was often overlooked by previous studies. A two‐peak seasonal variation in CH 4 fluxes was observed, with a small peak in the spring thawing period and a large one in the peak growing season. We detected a significant difference in the diurnal variation of CH 4 fluxes between the two seasons, with two peaks in the growing season and one peak in the nongrowing season. We found that the CH 4 fluxes during the growing season were well correlated with soil temperature, water table depth and gross primary production, whereas the CH 4 fluxes during the nongrowing season were highly correlated with soil temperature. Our results suggested that the CH 4 emission during the nongrowing season cannot be ignored and the vast wetlands on the Tibetan plateau will have the potential to exert a positive feedback on climate considering the increasing warming, particularly in the nongrowing season in this region.