Environmental Engineering Reference
In-Depth Information
A plenty of Bacteroidetes strains isolated from wetland soils and sediments were reported
to be anaerobic and saprophytic representative bacteria [52, 53]. Highlighting the unevenness
of the phylum, over 70% of all the Bacteroidetes sequences (12.8% of all bacterial sequences)
were assigned to class Flavobacteria. As a common heterotrophic obligate aerobe,
Flavobacteria was the second largest class in the dataset. It is widespread in various wetlands,
even in swine wastewater lagoon and constructed wetlands [54, 55]. The class
Sphingobacteria was represented by only 491 sequences, while the class Bacteroidia was
represented by only 75 sequences. ‗Undefined Bacteroidetes' comprised 65 sequences.
The most frequently observed genus in Flavobacteria was
Flavobacterium
(1459
sequences), which was also the most abundant bacterial genus in this dataset. A number of
species of
Flavobacterium
have been isolated from rhizosphere of wetland [52, 53].
3.2.3. Acidobacteria
Acidobacteria was the third largest phylum in our dataset, including 1345 sequences
assigned to 29 genera. Acidobacteria is a newly phylum, whose members are physiologically
diverse and ubiquitous in soils, but are under-represented in culture at present. There were
731 OTUs identified, with a Simpson diversity index of 0.0031 (Figure 5). Just over 90% of
all the acidobacterial sequences (9.7% of all bacterial sequences) were assigned to 21
unclassified groups, only 130 sequences represented to class Holophagae. In total, nearly 40%
of the Acidobacteria sequences were able to be classified to Gp1, which was the second
largest class of bacteria. The following classes were group Gp3 and then group Gp6, with 196
and 116 sequences, respectively.
As the reports, Acidobacteria group was more abundant in natural wetlands than in
created wetlands [10, 34], especially in freshwater sediment [34]. Acidobacteria has been
reported as the largest division in the active layer and the associated permafrost of a
moderately acidic wetland in Canada [11]. Future studies are needed to examine the
interrelations of environmental parameters with Acidobacteria, and individual populations
within subgroups [56].
