Temporal and spatial variations in methane emissions from the littoral zone of a shallow mid-latitude lake with steady methane bubble emission areas
Temporal and spatial variations in methane emissions from the littoral zone of a shallow mid-latitude lake with steady methane bubble emission areas
复制标题
DOI：
10.1016/j.agrformet.2020.108184
复制
发表时间：
2020-12
影响因子：
6.2
通讯作者：
H. Iwata;Kotomi Nakazawa;Himeka Sato;Masayuki Itoh;Y. Miyabara;R. Hirata;Yoshiyuki Takahashi;T. Tokida;R. Endo
中科院分区：
文献类型：
--
作者：
H. Iwata;Kotomi Nakazawa;Himeka Sato;Masayuki Itoh;Y. Miyabara;R. Hirata;Yoshiyuki Takahashi;T. Tokida;R. Endo
利用涡度相关技术研究了中纬度浅水湖泊（Suwa湖）沿岸的带甲烷（CH4）排放的时空变化。并结合湖泊沉积物和水体的溶解CH4测定和培养实验，对观测数据进行了补充。这个湖有稳定的气泡CH4排放的地区，形成强烈的斑点排放的CH4通量的空间变化。在其他地区，CH4通过扩散和幕式沸腾释放。该地区的CH4排放有明显的季节变化，反映了温度的变化，8月份的月平均排放量最大，为0.39 µ mol m− 2 s− 1。夏季较高的排放量是由于沉积物中较高的CH4产生量以及由此导致的较高的地表水溶解CH4浓度。气泡CH4排放受总静水压力的季节性控制，在较低的压力下排放量较大，说明压力对气泡排放量有一定的调节作用。同位素分析表明，这种甲烷是生物产生的.据估计，这种天然气渗漏每年排放1.9兆克的甲烷。与其他内陆沃茨涡动相关研究相比，从苏瓦湖的CH 4排放量可能是大的纬度。这可能与富营养化有关，富营养化增加了CH4的产生。
Temporal and spatial variations in methane (CH 4) emissions from the littoral zone of a shallow mid-latitude lake, Lake Suwa, were examined using the eddy covariance technique. The observation data were supplemented with dissolved CH 4 measurement and incubation experiments of lake sediment and water. This lake had areas with steady bubble CH 4 emissions, shaping the spatial variation in CH 4 flux with strong spot emissions. In the other areas, CH 4 was emitted via diffusion and episodic ebullition. CH 4 emissions from this area had a clear seasonal variation, reflecting temperature variations, with a maximum monthly mean emission of 0.39 µ mol m− 2 s− 1 in August. The higher emission in summer was due to higher CH 4 production in the sediment and the resulting higher dissolved CH 4 concentration in the surface water. The steady bubble CH 4 emission was seasonally controlled by the total hydrostatic pressure, with higher emission under lower pressure, suggesting regulation of the amount of bubbles emitted from the lake bottom by pressure. Isotope analysis revealed that this CH 4 was produced biologically. This natural gas seepage was estimated to emit 1.9 Mg of CH 4 annually. Compared with other eddy covariance studies over inland waters, CH 4 emissions from Lake Suwa may be large for the latitude. This may be related to eutrophication, which enhances CH 4 production.