Short-term field observations of nitrous oxide saturations in Lake Taihu, China: the need for high temporal resolution studies.
Short-term field observations of nitrous oxide saturations in Lake Taihu, China: the need for high temporal resolution studies.
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DOI：
10.2134/jeq2009.0251
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发表时间：
2010-09
影响因子：
2.4
通讯作者：
Shi-lu Wang;K. Yeager;G. Wan;Congqiang Liu;F. Tao;C. Fan
中科院分区：
文献类型：
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作者：
Shi-lu Wang;K. Yeager;G. Wan;Congqiang Liu;F. Tao;C. Fan
对控制水生一氧化二氮 (N2O) 产生的过程的不完全了解部分是由于缺乏描述 N2O 产生的时间分辨率的现场数据。为了解决这个问题，我们在两个调查期（2003 年 7 月和 9 月）每小时直接测量太湖（中国东部一个大型富营养化湖泊）的 N2O 饱和度（相对于大气分压）。 7 月 N2O 饱和度显示出明显的昼夜模式，与其他人在亚热带溪流中观察到的情况相反，但与从孵化的河口沉积物中观察到的 N2O 排放相似。相关分析表明，生物地球化学过程在很短的时间内对 N2O 产生起到重要的控制作用。一氧化二氮的产生过程不仅受到与微藻光合作用相关的O2动力学的调节，而且与沉积物-水界面的有机物腐烂密切相关。虽然太湖 N2O 通量的大规模变化（约 25 倍）是氮负荷变化的函数，但沉积物-水界面上 O2 和 N 转化的生物地球化学过程对极短时间尺度内 N2O 产生的调节具有显着（两倍）的影响。此外，显然需要开展高时间分辨率研究，重点是全面了解湖相 N2O 的产生，包括自然和人为负荷以及生物地球化学转化过程。
The incomplete understanding of the processes which control aquatic nitrous oxide (N2O) production is partially due to a lack of onsite data with which to describe the temporal resolution of N2O production. To help resolve this, we directly measured the N2O saturation (relative to atmospheric partial pressure) on an hourly basis over two survey periods (July and September 2003) in Lake Taihu, a large eutrophic lake in eastern China. July N2O saturations displayed a distinct diurnal pattern, opposite to those observed by others in subtropical streams, but similar to N2O emissions observed from incubated estuarine sediments. Correlative analyses indicate that biogeochemical processes operate as important controls on N2O production over very short time scales. Nitrous oxide production processes are not only regulated by O2 dynamics related to microalgal photosynthesis, but also closely related to organic matter decay at the sediment-water interface. While large-scale changes (approximately 25-fold) in N2O fluxes in Lake Taihu are a function of variable N loading, biogeochemical processes concerning O2 and N transformation at the sediment-water interface have significant (-twofold) impacts on the regulation of N2O production over very short time scales. Further, high temporal resolution research focused on developing a comprehensive understanding of lacustrine N2O production, including natural and anthropogenic loading and biogeochemical transformation processes, is clearly needed.