State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.
College of Geographical Sciences, East China Normal University, Shanghai, 200241, China.
Appl Microbiol Biotechnol. 2016 Oct;100(19):8573-82. doi: 10.1007/s00253-016-7659-5. Epub 2016 Jun 17.
For the past few decades, human activities have intensively increased the reactive nitrogen enrichment in China's coastal wetlands. Although denitrification is a critical pathway of nitrogen removal, the understanding of denitrifier community dynamics driving denitrification remains limited in the coastal wetlands. In this study, the diversity, abundance, and community composition of nirS-encoding denitrifiers were analyzed to reveal their variations in China's coastal wetlands. Diverse nirS sequences were obtained and more than 98 % of them shared considerable phylogenetic similarity with sequences obtained from aquatic systems (marine/estuarine/coastal sediments and hypoxia sea water). Clone library analysis revealed that the distribution and composition of nirS-harboring denitrifiers had a significant latitudinal differentiation, but without a seasonal shift. Canonical correspondence analysis showed that the community structure of nirS-encoding denitrifiers was significantly related to temperature and ammonium concentration. The nirS gene abundance ranged from 4.3 × 10(5) to 3.7 × 10(7) copies g(-1) dry sediment, with a significant spatial heterogeneity. Among all detected environmental factors, temperature was a key factor affecting not only the nirS gene abundance but also the community structure of nirS-type denitrifiers. Overall, this study significantly enhances our understanding of the structure and dynamics of denitrifying communities in the coastal wetlands of China.
在过去的几十年中，人类活动强烈增加了中国沿海湿地的活性氮富集。尽管反硝化作用是氮去除的关键途径，但在沿海湿地中，对驱动反硝化作用的反硝化菌群落动态的理解仍然有限。在这项研究中，分析了 nirS 编码反硝化菌的多样性、丰度和群落组成，以揭示它们在中国沿海湿地中的变化。获得了多样化的 nirS 序列，其中 98%以上与从水生系统（海洋/河口/沿海沉积物和缺氧海水）获得的序列具有相当大的系统发育相似性。克隆文库分析表明，nirS 携带反硝化菌的分布和组成具有显著的纬度分化，但没有季节性变化。典范对应分析表明，nirS 编码反硝化菌的群落结构与温度和铵浓度显著相关。nirS 基因丰度范围为 4.3×10(5)至 3.7×10(7)拷贝 g(-1)干沉积物，具有显著的空间异质性。在所检测的所有环境因素中，温度不仅是影响 nirS 基因丰度，而且是影响 nirS 型反硝化菌群落结构的关键因素。总的来说，这项研究显著提高了我们对中国沿海湿地反硝化菌群落结构和动态的理解。
