Impacts of vegetation, tidal process, and depth on the activities, abundances, and community compositions of denitrifiers in mangrove sediment

Abstract

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.

Changes in land use driven by urbanization impact nitrogen cycling and the microbial community composition in soils

“…Primers and conditions used for quantifying denitrifiers ( nirK, nirS and nosZ I) and nitrifiers (archaeal and bacterial amoA ) were described in previous studies with modifications5556 (Supplementary Table S9). The primers, nosZ-II-F/nosZ-II-R, 515 F/907 R and arch21F/arch958R were used to target the nosZ clade II communities, bacteria and archaea 16 S rRNA genes, respectively (Supplementary Table S9).…”

Major Processes Shaping Mangroves as Inorganic Nitrogen Sources or Sinks: Insights From a Multidisciplinary Study

“…However, analysis of stable multi‐isotopes of nitrogen forms (e.g., 15 N and 18 O of nitrate, ammonium, and N 2 O) is rarely applied to define nitrogen source and cycling processes involved in the mangrove system. Furthermore, nitrogen biogeochemistry is mostly microbe driven, but microbiological identification is rarely incorporated into biogeochemical studies of mangrove systems (Amano et al, ; Li & Gu, ; Wang et al, ). Given that mangrove nitrogen biogeochemistry is diverse over time and space, a multidisciplinary approach is vital to reveal the underlying mechanisms and major processes controlling nitrogen cycling and outwelling across mangrove wetlands to hydrosphere and atmosphere.…”

Insights into the role of plant on ammonia-oxidizing bacteria and archaea in the mangrove ecosystem

“…4). In addition, denitrifier communities were also convinced to be easily shifted by these two wetland plants in mangrove sediment in our previous study (Wang et al 2014). Consequently, plant exhibited a great capacity to shape the niches of microbes involved in nitrogen cycling as well the potential in affecting the nitrogen balance.…”