Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, No. 1000 Jinqi Road, Shanghai 201403, China; Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
Sci Total Environ. 2014 Aug 15;490:1029-36. doi: 10.1016/j.scitotenv.2014.05.096. Epub 2014 Jun 7.
This study measured the microbial processes of anaerobic ammonium oxidation (anammox) and denitrification in sediment sampled from two sites in the estuary of an inland river (Koisegawa River, Ibaragi prefecture, Japan) using a nitrogen isotope pairing technique (IPT). The responses of anammox and denitrification activities to temperature and nitrate concentration were also evaluated. Further, to elucidate the correlation between anammox and denitrification processes, an inhibition experiment was conducted, using chlorate to inhibit the first step of denitrification. Denitrification activity was much higher than anammox activity, and it reached a maximum at the surface layer in February 2012. Denitrification activity decreased as sediment depth increased, and a similar phenomenon was observed for anammox activity in the sediment of site A, where aquatic plants were absent from the surroundings. The activities of both denitrification and anammox were temperature-dependent, but they responded differently to changes in incubation temperature. Compared to a linear increase in denitrification as temperature rose to 35 °C, the optimal temperature for anammox was 25 °C, after which the activity decreased sharply. At the same time, both anammox and denitrification activities increased with NO3(-) concentration. The Michaelis-Menten kinetic constants (Vmax and Km) of denitrification were significantly higher than those of the anammox process. Furthermore, anammox activity decreased accordingly when the first step of denitrification was inhibited, which probably reduced the amount of the intermediate NO2(-). Our study provides the first direct exploration of the denitrification-dependent correlation of anammox activity in the sediment of inland river.
本研究采用氮同位素配对技术（IPT），测量了日本内陆河流河口（利根川，茨城县）两个地点沉积物中厌氧氨氧化（anammox）和反硝化过程。还评估了 anammox 和反硝化活性对温度和硝酸盐浓度的响应。此外，为了阐明 anammox 和反硝化过程之间的相关性，进行了抑制实验，使用氯酸盐抑制反硝化的第一步。反硝化活性远高于 anammox 活性，并且在 2012 年 2 月达到表层的最大值。反硝化活性随沉积物深度的增加而降低，在 A 点沉积物中也观察到类似的现象，A 点周围没有水生植物。反硝化和 anammox 的活性均受温度的影响，但它们对孵育温度的变化反应不同。与反硝化随温度升高至 35°C 呈线性增加相比，anammox 的最佳温度为 25°C，之后活性急剧下降。同时，anammox 和反硝化活性均随 NO3(-)浓度的增加而增加。反硝化的米氏常数（Vmax 和 Km）明显高于 anammox 过程。此外，当抑制反硝化的第一步时，anammox 活性会相应降低，这可能会减少中间产物 NO2(-)的量。本研究首次直接探索了内陆河沉积物中反硝化依赖的 anammox 活性相关性。
