Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dubendorf, Switzerland.
Sci Rep. 2017 Jan 10;7:40173. doi: 10.1038/srep40173.
Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN md), with anammox activities of 0.005-0.74 nmolN gsoil h, which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75-1.4 × 10copies gsoil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <10copies gsoil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.
厌氧氨氧化（anammox）被认为是氮循环的重要过程，但对其在地下生物圈中的作用知之甚少。在这项研究中，我们使用同位素示踪技术、（q）PCR 检测、16S rRNA 和 hzsB 基因克隆文库以及土壤芯样品的营养状况，调查了来自中国天津（20 米深）和瑞士巴塞尔（10 米深）旱地土壤芯中 anammox 细菌的存在、丰度和作用。包气带（饱和水）中的 anammox 对氮损失（高达 0.675gN md）的贡献为 37.5-67.6%，anammox 活性为 0.005-0.74nmolN gsoil h，甚至高于反硝化速率。相比之下，在非饱和带未检测到显著的 anammox。在包气带中观察到较高的 anammox 细菌细胞密度（0.75-1.4×10copies gsoil），氨氧化细菌（AOB）可能是 anammox 细菌亚硝酸的主要来源。非饱和带土壤中的 anammox 细菌细胞均<10copies gsoil。我们认为地下环境为 anammox 细菌提供了有利的小生境，其对氮循环和地下水硝酸盐去除的贡献似乎比以前已知的要大得多。
