Both Bacteria and Archaea might be involved in various biogeochemical processes in lacustrine sediment ecosystems. However, the factors governing the intra-lake distribution of sediment bacterial and archaeal communities in various freshwater lakes remain unclear. The present study investigated the sediment bacterial and archaeal communities in 13 freshwater lakes on the Yunnan Plateau. Quantitative PCR assay showed a large variation in bacterial and archaeal abundances. Illumina MiSeq sequencing illustrated high bacterial and archaeal diversities. Bacterial abundance was regulated by sediment total organic carbon and total nitrogen, and water depth, while nitrate nitrogen was an important determinant of bacterial diversity. Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, and Verrucomicrobia were the major components of sediment bacterial communities. Proteobacteria was the largest phylum, but its major classes and their proportions varied greatly among different lakes, affected by sediment nitrate nitrogen. In addition, both Euryarchaeota and Crenarchaeota were important members in sediment archaeal communities, while unclassified Archaea usually showed the dominance.

Distribution of sediment bacterial and archaeal communities in plateau freshwater lakes.

Impact of long-term fertilization practices on the abundance and composition of soil bacterial communities in Northeast China.

The vertical distribution of bacterial and archaeal communities in the water and sediment of Lake Taihu

Both planktonic and sediment bacterial assemblages are the important components of freshwater lake ecosystems. However, their spatiotemporal shift and the driving forces remain still elusive. Eutrotrophic Dianchi Lake and mesotrophic Erhai Lake are the largest two freshwater lakes on the Yunnan Plateau (southwestern China). The present study investigated the spatiotemporal shift in both planktonic and sediment bacterial populations in these two plateau freshwater lakes at different trophic status. For either lake, both water and sediment samples were collected from six sampling locations in spring and summer. Bacterioplankton community abundance in Dianchi Lake generally far outnumbered that in Erhai Lake. Sediment bacterial communities in Erhai Lake were found to have higher richness and diversity than those in Dianchi Lake. Sediments had higher bacterial community richness and diversity than waters. The change patterns for both planktonic and sediment bacterial communities were lake-specific and season-specific. Either planktonic or sediment bacterial community structure showed a distinct difference between in Dianchi Lake and in Erhai Lake, and an evident structure difference was also found between planktonic and sediment bacterial communities in either of these two lakes. Planktonic bacterial communities in both Dianchi Lake and Erhai Lake mainly included Proteobacteria (mainly Alpha-, Beta-, and Gammaproteobacteria), Bacteroidetes, Actinobacteria, Cyanobacteria, and Firmicutes, while sediment bacterial communities were mainly represented by Proteobacteria (mainly Beta- and Deltaproteobacteria), Bacteroidetes, Chlorobi, Nitrospirae, Acidobacteria, and Chloroflexi. Trophic status could play important roles in shaping both planktonic and sediment bacterial communities in freshwater lakes.

Spatiotemporal variation of planktonic and sediment bacterial assemblages in two plateau freshwater lakes at different trophic status.

Sediment microbial communities play an important role in lake trophic status. This study determined millions of Illumina reads (16S rRNA gene amplicons) to compare the bacterial communities in moderately eutrophic, lightly eutrophic, and moderately trophic regions using a technically consistent approach. The results indicated that the sediments from moderately eutrophic and trophic lake had the higher bacterial diversity than lightly eutrophic lake. Proteobacteria was the most abundant phylum (22.7%-86.2%) across samples from three regions. The sediments from moderately eutrophic region were enriched with Chloroflexi and Nitrospirae. Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes were enriched in the sediments from lightly eutrophic lake. The sediments from moderately trophic lake contained a high abundance of Acidobacteria and Deltaproteobacteria because of the low pH of the sediments in this lake. In moderately eutrophic region, Nitrospira held an absolute predominance, while Lysobacter and Flavobacterium were the most predominant genera in lightly eutrophic region. Temperature was the main factor influencing the bacterial community in the three lakes. The bacterial communities in the sediment samples obtained from moderately eutrophic lake were associated with nutrient concentration, whereas organic matter and total nitrogen contents mainly influenced the bacterial communities in sediments obtained from lightly eutrophic lake and moderately trophic lake, respectively.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mbo3.503

Characterization of sediment bacterial communities in plain lakes with different trophic statuses

Vertical distribution of bacterial community structure was investigated in the sediments of two eutrophic lakes of China, Lake Taihu and Lake Xuanwu. Profiles of bacterial communities were generated using a molecular fingerprinting technique, denaturing gradient gel electrophoresis (DGGE) followed by DNA sequence analysis, and the results were interpreted with multivariate statistical analysis. To assess changes in the genetic diversity of bacterial communities with changing depth, DGGE banding patterns were analysed by cluster analysis. Distinct clusters were recognized in different sampling stations of Lake Taihu. Canonical correspondence analysis (CCA) was carried out to infer the relationship between environmental variables and bacterial community structure. DGGE samples collected at the same sampling site clustered together in both lakes. Total phosphorus, organic matter and pH were considered to be the key factors driving the changes in bacterial community composition.

Vertical distribution of bacterial community structure in the sediments of two eutrophic lakes revealed by denaturing gradient gel electrophoresis (DGGE) and multivariate analysis techniques

Jiayun Li

Papers

Vertical distribution of bacterial community structure in the sediments of two eutrophic lakes revealed by denaturing gradient gel electrophoresis (DGGE) and multivariate analysis techniques