幕阜山古-今土壤微生物垂直分布格局及功能群差异OA

To elucidate the distribution characteristics of culturable microorganisms in buried paleosols and modern mountain soils from Mufu Mountains,this study focused on the eluvial(Ab)and illuvial(Bb)horizons of buried paleosols,as well as the eluvial(A)and illuvial(B)horizons of modern mountain soils,establishing a soil profile sequence for analysis.The dilution plate method was employed to quantify the abundance of bacteria,fungi,actinomycetes,and nitrogen-and phosphorus-transforming microorganisms within these distinct soil horizons.Statistical methods were subsequently employed to analyze the observed differences.The results indicated that the vertical distribution pattern of the three major groups of culturable microorganisms(bacteria>actinomycetes>fungi)was stable,with the relative abundance not affected by soil types.Nitrogen-cycling microorganisms were most enriched in the Ab horizon of buried paleosols,where the abundance of aerobic nitrogen-fixing bacteria and ammonifying bacteria was significantly higher than that in the corresponding horizon of modern soils,and there were always differences in the abundance of nitrifying bacteria and other microbial groups.The distribution of phosphorus-transforming bacteria showed intra-horizon independence.There was no significant association between organic and inorganic phosphorus-transforming bacteria.Only the inorganic phosphorus-transforming bacteria in the Ab and Bb horizons of buried paleosols had vertical differences.These findings demonstrated that distinct differences existed between buried paleosols and modern mountain soils regarding both the composition and quantitative distribution of culturable microorganisms.Modern mountain soils generally harbored higher overall abundance of the three major microbial groups,while the paleosol Ab horizon exhibited a relative advantage in terms of nitrogen-and phosphorus-transforming microorganisms.