Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China.
Appl Microbiol Biotechnol. 2014 Nov;98(22):9375-87. doi: 10.1007/s00253-014-6017-8. Epub 2014 Aug 23.
Coastal mangrove wetland is well known to be intense in nitrogen cycling. The tidal process and plants are key factors in controlling the microbial processes in wetlands. However, mechanisms on how these factors and their interactions affect the microorganisms involved in denitrification remain poorly understood. In this study, the impacts of vegetation (bulk, Kandelia obovata, and Spartina alterniflora) and tidal process (falling tide and rising tide) on denitrification activities, abundances, and community compositions of denitrifiers in the sediments from different depths (0-5 and 5-10 cm) were investigated in a microcosm experiment. A significant enhancement of denitrification activities and gene abundances (nirS, nirK, and nosZ) in the vegetated sediments was observed. Activities and abundances were significantly higher in the 0-5-cm sediments when compared with the 5-10-cm counterparts. The effect of interaction between vegetation and tide or depth was also significant. Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that not only vegetation but also plant species had a significant impact on the community compositions of nirK denitrifiers, while the tidal process affected the community compositions of nirS and nosZ denitrifiers but not nirK denitrifiers. However, depth only significantly shaped the nirS denitrifier communities. These findings demonstrate the effects of these factors and their interactions in shaping the denitrifiers in sediments.
滨海红树林湿地以氮循环强度大而闻名。潮汐过程和植物是控制湿地微生物过程的关键因素。然而，这些因素及其相互作用如何影响参与反硝化作用的微生物的机制仍知之甚少。在这项研究中，通过微宇宙实验研究了植被（整体、秋茄和互花米草）和潮汐过程（落潮和涨潮）对不同深度（0-5 和 5-10 cm）沉积物中反硝化活性、反硝化菌丰度和群落组成的影响。结果表明，在有植被的沉积物中，反硝化活性和基因丰度（nirS、nirK 和 nosZ）显著增强。与 5-10-cm 相比，0-5-cm 沉积物中的活性和丰度明显更高。植被与潮汐或深度之间的相互作用的影响也很显著。末端限制性片段长度多态性（T-RFLP）分析表明，不仅是植被，而且植物物种对 nirK 反硝化菌的群落组成也有显著影响，而潮汐过程影响 nirS 和 nosZ 反硝化菌的群落组成，但不影响 nirK 反硝化菌。然而，只有深度显著影响 nirS 反硝化菌群落。这些发现表明了这些因素及其相互作用在塑造沉积物中反硝化菌方面的影响。
