长江口海域夏季沉积物反硝化细菌数量及反硝化作用

Quantification of denitrifying bacteria and denitrification process in surface sediment at adjacent sea area of the Yangtze River Estuary in summer

选择长江口邻近海域8个站位,采用乙炔抑制法进行现场模拟培养,研究了夏季表层沉积物中反硝化细菌数量及反硝化作用.结果表明,该海域反硝化细菌数量为3.9×105～110.0×105个/g,盐度、溶解氧是反硝化细菌数量的主要影响因子;反硝化速率为101.3～731.9μmol/(m2·h),与反硝化细菌数量的相关系数为0.950.反硝化速率,同时受环境中盐度、溶解氧和氨氮含量的显著影响;研究海区内反硝化作用产生的氮通量约为8.19×105kg/d,约为相应海区初级生产消耗无机氮量的1/3.

The role of denitrifying bacteria and the influence of environmental factors such as temperature and salinity on the denitriflcation process in summer in surface sediment at adjacent sea area of the Yangtze River Estuary, China was evaluated. The quantities of denitrifying bacteria at the eight sampling sites ranged from 3.9×10^5 cells/g to 110.0× 10^5 cells/g, which were significantly correlated with salinity and dissolved oxygen. The average denitriflcation rates measured using the acetylene inhibition technique ranged from 101.3μmol/（m^2·h） to 731.9μmol/（m^2·h）. Their significant correlationship with the quantity of denitrifying bacteria （P=0.950） indicated that denitrifying bacteria was the determining factor. The denitrification rate was also primarily affected by the salinity and the concentrations of DO and ammonia. The nitrogen flux by the denitrification process was calculated to be 8.19×10^5kg/d, which was equivalent to nearly one-third of the inorganic nitrogen consumption amount during primary production process at the corresponding area. Thus, bacteria denitriflcation played a significant role in the cycling and removal of nitrogen at study sea area.