Methane emissions during different freezing-thawing periods from a fen on the Qinghai-Tibetan Plateau: Four years of measurements
Methane emissions during different freezing-thawing periods from a fen on the Qinghai-Tibetan Plateau: Four years of measurements
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DOI：
10.1016/j.agrformet.2020.108279
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发表时间：
2021-02
影响因子：
6.2
通讯作者：
Huai Chen;Xin-wei Liu;Dan Xue;Dan Zhu;Wei Zhan;Wei Li;N. Wu;Gang Yang
中科院分区：
文献类型：
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作者：
Huai Chen;Xin-wei Liu;Dan Xue;Dan Zhu;Wei Zhan;Wei Li;N. Wu;Gang Yang
甲烷（CH 4）通量从高山泥炭地，特别是在冻融循环，影响全球CH 4预算知之甚少。本研究结合涡度相关法、温育实验和高通量测序技术，观测了一个高山沼泽在4年的解冻-冻结期的CH 4通量。分析了甲烷产生潜力和产甲烷古菌对气候变化的响应。我们发现相对较高的平均年累积CH 4排放量为37.7 g CH 4-C m−2。融化期是CH 4排放的主要贡献者：较暖、较长的融化期对CH 4年收支的贡献率为69.1-88.6%。非解冻期也有贡献，较短的冻融期占18.5%，较短的解冻期占8.8%。在一年的过程中，排放量在生长高峰期和解冻和冻结开始时达到峰值。相比之下，排放量在冻结期间没有实质性变化。日平均排放量在解冻期最高，在冻结期最低。4个时段CH 4排放日变化规律相似，峰值出现在12：00 ~ 18：00，最低值出现在00：00左右。不同融冻期地下水位和温度是控制CH 4排放的主导因子。我们的研究结果表明，CH 4排放量从泥炭地将大幅变化的CH 4生产，微生物组成，和模式的解冻-冻结循环的变化与全球变暖。因此，需要经常监测更多泥炭地的CH 4通量，并对甲烷生成和相关微生物进行原位监测，以提供CH 4通量和影响它们的解冻-冻结过程的清晰图像。
How methane (CH4) fluxes from alpine peatlands, especially during freeze-thaw cycles, affect the global CH4budget is poorly understood. The present research combined the eddy covariance method, incubation experiments and high-throughput sequencing to observe CH4flux from an alpine fen during thawing-freezing periods over a period of four years. The response of CH4production potential and methanogenic archaea to climate change was analyzed. We found a relatively high mean annual cumulative CH4emission of 37.7 g CH4-C m−2. The dominant contributor to CH4emission was the thawing period: warmer, longer thawing periods contributed 69.1-88.6% to the annual CH4budget. Non-thawing periods also contributed, with shorter frozen-thawing periods accounting for up to 18.5% and shorter thawing-freezing periods accounting for up to 8.8%. Over the course of a year, emission peaked in the peak growing season and at onset of thawing and freezing. In contrast, emission did not vary substantially during the frozen period. Daily mean emission was highest during the thawing period and lowest during the frozen period. Diurnal patterns of CH4emission were similar among the four periods, with peaks ranging from 12:00 to 18:00 and the lowest emission around 00:00. Water table and temperature were the dominant factors controlling CH4emissions during different thawing-freezing periods. Our results suggest that CH4emission from peatland will change substantially as CH4production, microbial composition, and patterns of thawing-freezing cycles change with global warming. Therefore, frequent monitoring of CH4fluxes in more peatlands andin situmonitoring of methanogenesis and related microbes are needed to provide a clear picture of CH4fluxes and the thawing-freezing processes that affect them.