池塘沉积物对上覆水脱氮作用的初步探究

Preliminary study on denitrification of overlying water by pond sediments

以池塘沉积物为研究对象,研究其对上覆水的脱氮效果和微生物群落的影响。试验使用小苏打(NaHCO3)调控水体碱度,上覆水初始碱度(以CaCO3计)分别为A组(143.3±7.10)mg/L、B组(275.2±22.01)mg/L、C组(385.1±28.01)mg/L和D组(466.5±61.50)mg/L。结果显示:沉积物对上覆水体脱氮率为A组93.31%、B组93.54%、C组94.88%、D组93.53%,组间无显著性差异(P>0.05),碱度添加对沉积物脱氮效果无明显影响(P>0.05)。高通量结果显示,沉积物微生物群落门水平上变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)为主要优势菌门。优势菌属硫杆菌(Thiobacillus)、硫碱螺旋杆菌属(Thioalkalispira)均为硫自养反硝化为主的脱氮菌属。研究表明,池塘沉积物对上覆水具有明显脱氮效果,碱度调控对其无显著影响。

This study takes pond sediments as the object to study its effect on denitrification of overlying water and microbial community.In the experiment,baking soda(NaHCO3)was used to regulate the alkalinity of the water.The initial alkalinity of the overlying water(calculated as CaCO3)was 143.3±7.10 mg/L in group A,275.2±22.01 mg/L in group B,385.1±28.01 mg/L in group C and 466.5±61.50 mg/L in group D.The results showed that the rate of denitrification of overlying water by sediments was 93.31%in Group A,93.54%in Group B,94.88%in Group C and 93.53%in Group D.There was no significant difference between the groups(P>0.05).Addition of alkalinity had no significant effect on the nitrogen removal effect of sediments(P>0.05).High-throughput results showed that Proteobacteria,Bacteroidetes,Chloroflexi and Acidobacteria were the main dominant bacteria at the phylum level.The dominant genuses Thiobacillus and Thioalkalispira were both denitrifying bacteria mainly based on sulfur autotrophic denitrification.Studies have shown that pond sediments have an obvious denitrifying effect on overlying water,and there is no significant difference in alkalinity regulation.