Denitrifier communities differ in mangrove wetlands across China

Area of Science:

• Environmental microbiology
• Marine ecology
• Biogeochemistry

Background:

• Mangrove ecosystems harbor diverse microbial communities crucial for nutrient cycling.
• The nosZ gene is a key marker for nitrous oxide-reducing bacteria (denitrifier).
• Understanding denitrifier community structure is vital for nitrogen cycling in coastal environments.

Purpose of the Study:

• To investigate geographical variations in the nosZ-denitrifier community across Chinese mangroves.
• To identify environmental factors shaping denitrifier community structure and diversity.
• To analyze the distribution patterns of nosZ-denitrifier operational taxonomic units (OTUs).

Main Methods:

• Surface sediment sampling from six distinct mangrove locations in China.
• Quantification of nosZ gene abundance using quantitative PCR.
• Analysis of denitrifier community richness and diversity (Chao1, Shannon index).
• Community structure analysis using Hierarchical Cluster Analysis (HCA) and Principal Coordinate Analysis (PCoA).

Main Results:

• nosZ gene abundance ranged from 1.60 × 10^5 to 1.17 × 10^6 copies g^-1 dry sediment.
• Denitrifier community richness and diversity increased with decreasing latitude.
• Three distinct denitrifier community groups were identified, correlating with geographical location (south, middle, north).
• nosZ OTUs formed seven distinct clusters with varying distributions across mangroves.
• Total nitrogen (TN), total organic carbon (TOC), and salinity were identified as key shaping factors.

Conclusions:

• Mangrove denitrifier communities exhibit significant geographical variation across China.
• Latitude and environmental factors (TN, TOC, salinity) are primary drivers of denitrifier community structure.
• The findings provide insights into nitrogen cycling processes in mangrove ecosystems.