哭求垃圾填埋场 英文质料

accordance with major redox processes in these environments
implied by hydrochemical analyses.It was found that several
redox processes could take place simultaneously in many
cases ( Ludvigsen,1998 ),which is consistent with
coexistence of sulfate reducing bacteria and methanotrophic
bacteria in groundwater samples B and C.
A phylogenetic descri ption of dominant microbial
populations is an important step in understanding of ecological
processes in aquifers beneath a landfill.However,
phylogenetic affiliation alone is not sufficient to firmly connect
certain microbial taxa with a biochemical reaction,therefore
we can only hypothesize about its possible biochemical role.
On the other hand,evidences from other aspects can be used
to support the validity of our speculations.It is reasonable
that more sequences are related to complex compound
degrading fermentative bacteria in the samples B and C. For
example,2 sequences (3JL288 and 3ML292) are affiliated
with aminobacterium colombiense,an aminoacid degrading
obligate anaerobe.A sequence ( 3JL293) is affiliated with
Ilyobacter polytropus,a fermentative Fusobacterium which
specialized in the degradation of hydroaromatic compounds.
In this study,it is significative that phylogenetic information
showing variations of dominant microbial populations is in
accordance with hydrochemical changes of groundwater on the
whole.
3 　Conclusions
The results indicated that obvious changes of dominant
microbial populations had occurred in groundwater in
response to leachate from Laogang Landfill.Concentration
variations of dissolved redox relevant species suggested that
the dominating redox process had changed from denitrification
to methane production Psulfate reduction. The dominating
redox process determined is accordant with the closest
relatives of some dominant clones,based on their indications
on the ability to perform redox reactions in the GenBank
database.

respectively.From a statistical standpoint,each combined
genotype was generally regarded as a unique population(Yu,
2001).
From 45,49 and 48 combined genotypes in A,B and C
Libraries,there were 7,8 and 7 including 4 clones or more,
which been regarded as the representatives of the dominant
microbial populations.Inserts of one clone from each
dominant combined genotype were successfully partially
sequenced (≈600 bp ).Sequences were assigned to major
microbial groups and the closest known relatives were chosen
by searching in GenBank databases based on BLAST
similarities.Summary of phylogenetic affiliation of the
dominant microbial populations are shown in Table 2.
There is strong dominance by bacteria belonging to β2
Proteobacteria in the A library,while no clones showed
affiliation to β2 Proteobacteria,and relatively dominant
microbial groups are gram positive bacteria (e. g. Firmicutes,
Fusobacteria) in the libraries B and C. The results indicated
that there is a complete shift in the composition of the
dominant populations after landfilling.On the other hand,
there is no clear transition of dominant microbial populations
found between the sample B and C.
　　Based on the GenBank’s indications of the closest
relative of a retrieved sequence , a possible biochemical role
of the bacterium represented by the sequence could be
surmised. It should be noted that 1 sequence related to
genera capable of denitrification ( Azoarcus related ) were
retrieved.Remarkably,3 sequences are closely related to
sulfate reducers.Three sequences are associated with the
methanotrophic bacteria though no sequence affiliated with
methanogenic bacterium was encountered.This situation is in