Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361102, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China.
Sci Total Environ. 2020 Jan 1;698:134291. doi: 10.1016/j.scitotenv.2019.134291. Epub 2019 Sep 7.
Anaerobic ammonium oxidation (anammox), a microbial process in which NH is oxidized to N gas, is considered a significant nitrogen cycle process, but its significance in mangrove wetland sediments, particularly its depth- and genus-specific distribution and activity have remained uncertain. Here we report the vertical distribution, abundance, activity and role of anammox bacteria in mangrove sediments of Zhangjiang Estuary, China. We used stable isotope-tracer techniques, 16S rRNA and anammox bacterial functional gene (Hydrazine synthase B: hzsB) clone libraries and quantitative polymerase chain reaction (qPCR) assays, along with an assessment of nutrient profiles of sediment core samples. We observed a widespread occurrence of anammox bacteria at different depths of mangrove sediments. The abundance of anammox bacterial 16S rRNA and hzsB genes ranged from 0.41×10 to 9.74×10 and from 0.42×10 to 6.44×10 copies per gram of dry soil and peaked in the upper layer of mangrove sediments. We also verified the co-occurrence of different genera of anammox microorganisms in mangrove sediments, with Candidatus Scalindua and Candidatus Kuenenia being the dominant genera. Potential anammox rates ranged from 4.83 to 277.36 nmolN·g·d at different depths of sediment cores, and the highest rates were found in the deeper layer (70-100cm) of mangrove sediments. Scaling our findings up to the entire mangrove system, we estimated that anammox hotspots accounted for a loss of 751 gN·m·y, and contributed to over 12% of the nitrogen lost from the deeper layer of mangrove sediments in this region.
厌氧氨氧化（anammox）是一种微生物过程，其中 NH 被氧化为 N 气体，被认为是一种重要的氮循环过程，但它在红树林湿地沉积物中的重要性，特别是其深度和属特异性分布和活性仍然不确定。在这里，我们报告了中国漳江河口红树林沉积物中 anammox 细菌的垂直分布、丰度、活性和作用。我们使用稳定同位素示踪技术、16S rRNA 和 anammox 细菌功能基因（肼合酶 B：hzsB）克隆文库和定量聚合酶链反应（qPCR）检测，以及对沉积物芯样品的营养状况进行评估。我们观察到 anammox 细菌在红树林沉积物的不同深度广泛存在。anammox 细菌 16S rRNA 和 hzsB 基因的丰度范围分别为 0.41×10 至 9.74×10 和 0.42×10 至 6.44×10 拷贝/克干土，在红树林沉积物的上层达到峰值。我们还验证了不同属的 anammox 微生物在红树林沉积物中的共同存在，其中 Candidatus Scalindua 和 Candidatus Kuenenia 是主要属。不同深度沉积物芯的潜在 anammox 速率范围为 4.83 至 277.36 nmolN·g·d，最高速率出现在红树林沉积物的深层（70-100cm）。将我们的发现扩展到整个红树林系统，我们估计 anammox 热点导致了 751 gN·m·y 的损失，并对该地区红树林沉积物深层的氮损失贡献了超过 12%。
