Project description:Total seventy four bacteria were isolated from Lonar soda lake of Maharashtra state, India. Eleven isolates were identified using morphological, biochemical and molecular analysis. The bacteria isolated belonged to phylum firmicutes and proteobacteria. Majorities (eight) were firmicutes and three were proteobacteria. For the first time we are reporting Alcanivorax spp. which is a genus well known for its oil degradation capacity, indicate the probable existence of oil reservoir in vicinity of Lonar lake. In addition all the eleven bacteria are potential producers of industrially important enzymes, pigments, antibiotics as well.
Project description:Lake microbiota play a crucial role in geochemical cycles, influencing both energy flow and material production. However, the distribution patterns of bacterial communities in lake sediments remain largely unclear. In this study, we used 16S rRNA high-throughput sequencing technology to investigate the bacterial structure and diversity in sediments across different locations (six independent lakes) within Lianhuan Lake and analyzed their relationship with environmental factors. Our findings revealed that both the alpha and beta diversity of sediment bacterial communities varied significantly among the six independent lakes. Furthermore, changes between lakes had a significant impact on the relative abundance of bacterial phyla, such as Pseudomonadota and Chloroflexota. The relative abundance of Pseudomonadota was highest in Habuta Lake and lowest in Xihulu Lake, while Chloroflexota abundance was lowest in Habuta Lake and highest in Tiehala Lake. At the genus level, the relative abundance of Luteitalea was highest in Xihulu Lake compared to the other five lakes, whereas the relative abundances of Clostridium, Thiobacillus, and Ilumatobacter were highest in Habuta Lake. Mantel tests and heatmaps revealed that the relative abundance of Pseudomonadota was significantly negatively correlated with pH, while the abundance of Chloroflexota was significantly positively correlated with total phosphorus and total nitrogen in water, and negatively correlated with electrical conductivity. In conclusion, this study significantly enhances our understanding of bacterial communities in the different lakes within the Lianhuan Lake watershed.
Project description:Lake Sayram is an ancient cold water lake locating at a mountain basin in Xinjiang, China. The lake water is brackish, alkaline, unpolluted, and abundant in SO4(2-) and Mg(2+). The lacustrine ecosystem of Lake Sayram has been intensely investigated. However, profiles of the microbial communities in the lake remain largely unknown. In this study, taxonomic compositions of the planktonic and sedimentary bacterial communities in Lake Sayram were investigated using 16S rRNA metagenomics. The lacustrine bacterial communities were generally structured by environmental conditions, including the hydrological and physicochemical parameters. Proteobacteria was the dominating phylum. In the lake water, the genera Acinetobacter and Ilumatobacter held an absolute predominance, implying their metabolic significance. In the bottom sediment, biogeochemically significant bacteria and thermophilic or acidothermophilic extremophiles were recovered. In contrast to the planktonic bacteria, an appreciable portion of the sedimentary bacteria could not be classified into any known taxonomic unit, indicating the largely unknown bacteriosphere hiding in the bottom sediment of Lake Sayram.
Project description:This study assessed the diversity and composition of bacterial communities within soils and lake sediments from an Arctic lake area (London Island, Svalbard). A total of 2,987 operational taxonomic units were identified by high-throughput sequencing, targeting bacterial 16S rRNA gene. The samples from four sites (three samples in each site) were significantly different in geochemical properties and bacterial community composition. Proteobacteria and Acidobacteria were abundant phyla in the nine soil samples, whereas Proteobacteria and Bacteroidetes were abundant phyla in the three sediment samples. Furthermore, Actinobacteria, Chlorobi, Chloroflexi, Elusimicrobia, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria significantly varied in their abundance among the four sampling sites. Additionally, members of the dominant genera, such as Clostridium, Luteolibacter, Methylibium, Rhodococcus, and Rhodoplanes, were significantly different in their abundance among the four sampling sites. Besides, distance-based redundancy analysis revealed that pH (p < 0.001), water content (p < 0.01), ammonium nitrogen ([Formula: see text]-N, p < 0.01), silicate silicon ([Formula: see text]-Si, p < 0.01), nitrite nitrogen ([Formula: see text]-N, p < 0.05), organic carbon (p < 0.05), and organic nitrogen (p < 0.05) were the most significant factors that correlated with the bacterial community composition. The results suggest soils and sediments from a lake area in the Arctic harbor a high diversity of bacterial communities, which are influenced by many geochemical factors of Arctic environments.
Project description:The permanently stratified water columns in euxinic meromictic lakes produce niche environments for phototrophic sulfur oxidizers and diverse sulfur metabolisms. While Green Lake (Fayetteville, New York, NY) is known to host a diverse community of ecologically important sulfur bacteria, analyses of its microbial communities, to date, have been largely based on pigment analysis and smaller datasets from Sanger sequencing techniques. Here, we present the results of next-generation sequencing of the eubacterial community in the context of the water column geochemistry. We observed abundant purple and green sulfur bacteria, as well as anoxygenic photosynthesis-capable cyanobacteria within the upper monimolimnion. Amidst the phototrophs, we found other sulfur-cycling bacteria including sulfur disproportionators and chemotrophic sulfur oxidizers, further detailing our understanding of the sulfur cycle and microbial ecology of euxinic, meromictic lakes.
Project description:Global climate change is causing a wastage of glaciers and threatening biodiversity in glacier-fed ecosystems. The high turbidity typically found in those ecosystems, which is caused by inorganic particles and result of the erosive activity of glaciers is a key environmental factor influencing temperature and light availability, as well as other factors in the water column. Once these lakes loose hydrological connectivity to glaciers and turn clear, the accompanying environmental changes could represent a potential bottleneck for the established local diversity with yet unknown functional consequences. Here, we study three lakes situated along a turbidity gradient as well as one clear unconnected lake and evaluate seasonal changes in their bacterial community composition and diversity. Further, we assess potential consequences for community functioning. Glacier runoff represented a diverse source community for the lakes and several taxa were able to colonize downstream turbid habitats, although they were not found in the clear lake. Operational taxonomic unit-based alpha diversity and phylogenetic diversity decreased along the turbidity gradient, but metabolic functional diversity was negatively related to turbidity. No evidence for multifunctional redundancy, which may allow communities to maintain functioning upon alterations in diversity, was found. Our study gives a first view on how glacier-fed lake bacterial communities are affected by the melting of glaciers and indicates that diversity and community composition significantly change when hydrological connectivity to the glacier is lost and lakes turn clear.
Project description:As microorganisms are very sensitive to changes in the lake environment, a comprehensive and systematic understanding of the structure and diversity of lake sediment microbial communities can provide feedback on sediment status and lake ecosystem protection. Xiao Xingkai Lake (XXL) and Xingkai Lake (XL) are two neighboring lakes hydrologically connected by a gate and dam, with extensive agricultural practices and other human activities existing in the surrounding area. In view of this, we selected XXL and XL as the study area and divided the area into three regions (XXLR, XXLD, and XLD) according to different hydrological conditions. We investigated the physicochemical properties of surface sediments in different regions and the structure and diversity of bacterial communities using high-throughput sequencing. The results showed that various nutrients (nitrogen, phosphorus) and carbon (DOC, LOC, TC) were significantly enriched in the XXLD region. Proteobacteria, Firmicutes, and Bacteroidetes were the dominant bacterial phyla in the sediments, accounting for more than 60% of the entire community in all regions. Non-metric multidimensional scaling analysis and analysis of similarities confirmed that β-diversity varied among different regions. In addition, the assembly of bacterial communities was dominated by a heterogeneous selection in different regions, indicating the important influence of sediment environmental factors on the community. Among these sediment properties, the partial least squares path analysis revealed that pH was the best predictor variable driving differences in bacterial communities in different regions, with higher pH reducing beta diversity among communities. Overall, our study focused on the structure and diversity of bacterial communities in lake sediments of the Xingkai Lake basin and revealed that high pH causes the β-diversity of bacterial communities in the sediment to decrease. This provides a reference for further studies on sediment microorganisms in the Xingkai Lake basin in the future.
Project description:Bacterial and archaeal diversity was examined in a sediment core from Lake Bonney, Antarctica. Members of the Archaea showed both low abundance and diversity, whereas bacterial diversity was moderately high and some phyla were fairly abundant, even in geologically old samples. Microbial diversity correlated with sample texture and differed in silty and coarse samples.
Project description:Great Salt Lake (GSL), located northwest of Salt Lake City, UT, is the largest terminal lake in the USA. While the average salinity of seawater is ~3.3%, the salinity in GSL ranges between 5% and 28%. In addition to being a hypersaline environment, GSL also contains toxic concentrations of heavy metals, such as arsenic, mercury, and lead. The extreme environment of GSL makes it an intriguing subject of study, both for its unique microbiome and its potential to harbor novel natural product-producing bacteria, which could be used as resources for the discovery of biologically active compounds. Though work has been done to survey and catalog bacteria found in GSL, the Lake's microbiome is largely unexplored, and little to no work has been done to characterize the natural product potential of GSL microbes. Here, we investigate the bacterial diversity of two important regions within GSL, describe the first genomic characterization of Actinomycetota isolated from GSL sediment, including the identification of two new Actinomycetota species, and provide the first survey of the natural product potential of GSL bacteria.
Project description:The meromictic Lake Cadagno is characterized by a compact chemocline with high concentrations of anoxygenic phototrophic purple and green sulfur bacteria. However, a complete picture of the bacterial diversity, and in particular of effects of seasonality and compartmentalization is missing. To characterize bacterial communities and elucidate relationships between them and their surrounding environment high-throughput 16S rRNA gene pyrosequencing was conducted. Proteobacteria, Chlorobi, Verrucomicrobia, and Actinobacteria were the dominant groups in Lake Cadagno water column. Moreover, bacterial interaction within the chemocline and between oxic and anoxic lake compartments were investigated through fluorescence in situ hybridization (FISH) and flow cytometry (FCM). The different populations of purple sulfur bacteria (PSB) and green sulfur bacteria (GSB) in the chemocline indicate seasonal dynamics of phototrophic sulfur bacteria composition. Interestingly, an exceptional bloom of a cyanobacteria population in the oxic-anoxic transition zone affected the common spatial distribution of phototrophic sulfur bacteria with consequence on chemocline location and water column stability. Our study suggests that both bacterial interactions between different lake compartments and within the chemocline can be a dynamic process influencing the stratification structure of Lake Cadagno water column.