Microbial Community Composition in Thermal Waters from the Lindian Geothermal Field (Songliao Basin, North-Eastern China)

Influence of Geothermal Fumaroles in Driving the Microbial Community Dynamics and Functions of Adjacent Ecosystems

Growing evidence suggests that the hydrochemical properties of geothermal fumaroles may play a crucial role in shaping the diversity and functions of microbial communities in various environments. In the present study, the impact of geothermal furaneols on the microbial communities and their metabolic functions across the rock-soil-plant continuum was explored considering varying distances from the fumarole source. The results revealed that bacterial phylum Proteobacteria was predominant in all sample types, except in the 10 m rock sample, irrespective of the sampling distance. Archaeal phyla, such as Euryarchaeota and Crenarchaeota, were more prevalent in rock and soil samples, whereas bacterial phyla were more prevalent in plant samples. Thermoacidophilic archaeons, including Picrophilus, Ferroplasma, and Thermogymnomonas were dominant in rocks and soil samples of 1 and 5 m distances; acidophilic mesophiles, including Ferrimicrobium and Granulicella were abundant in the rhizoplane samples, whereas rhizosphere-associated microbes including Pseudomonas, Pedobacter, Rhizobium, and Novosphingobium were found dominant in the rhizosphere samples. The functional analysis highlighted the higher expression of sulfur oxidative pathways in the rock and soil samples; dark iron oxidation and nitrate/nitrogen respiratory functions in the rhizosphere samples. The findings underscore microbial adaptations across the rock-soil-plant continuum, emphasizing the intricate relationship between geothermal fumaroles and microbial communities in adjacent ecosystems. These insights offer a crucial understanding of the evolution of microbial life and highlight their pivotal roles in shaping ecosystem dynamics and functions.

Isolation and Characterization of Thermophilic Bacteria from a Hot Spring in the State of Hidalgo, Mexico, and Geochemical Analysis of the Thermal Water

Hot springs worldwide can be a source of extremophilic microorganisms of biotechnological interest. In this study, samplings of a hot spring in Hidalgo, Mexico, were conducted to isolate, identify, and characterize morphologically, biochemically, and molecularly those bacterial strains with potential industrial applications. In addition, a physicochemical and geochemical examination of the hot spring was conducted to fully understand the study region and its potential connection to the strains discovered. The hot spring was classified as sulfate-calcic according to the Piper Diagram; the hydrogeochemical analysis showed the possible interactions between minerals and water. Eighteen bacterial strains were isolated with optimal growth temperatures from 50 to 55 °C. All strains are Gram-positive, the majority having a rod shape, and one a round shape, and 17 produce endospores. Hydrolysis tests on cellulose, pectin, and xylan agar plates demonstrated enzymatic activity in some of the strains. Molecular identification through the 16S rDNA gene allowed classification of 17 strains within the Phylum Firmicutes and one within Deinococcus-Thermus. The bacterial strains were associated with the genera Anoxybacillus, Bacillus, Anerunibacillus, Paenibacillus, and Deinococcus, indicating a diversity of bacterial strains with potential industrial applications.

Genetic Analysis of Geothermal Resources in Deep-Seated Fault Area in Tonghe County, Northeast China and Implications of Geothermal Exploration

Northeast China is an area with high energy consumption and high carbon emissions, and the utilization of geothermal resources can effectively overcome these problems. However, there are few geothermal manifestations in Northeast China and no systematic method for geothermal exploration at present, which hinders the utilization of geothermal resources. Here, a systematic analysis, including hydrochemistry, petrology, isotopes, controlled source audio magnetotelluric sounding, drilling, and temperature curve of two boreholes was carried out to investigate the genesis of geothermal resources in Tonghe County, Northeast China, along the Yilan-Yitong lithospheric fault (YYF). We found that the geothermal water is alkaline Na-HCO3 type water, is of local meteoric origin, and is recharged from the hilly area with an elevation of ~280 m around the study area. We established a geothermal water circulation path model: (1) cold water infiltrated along the YYF to a depth of 2–3 km, (2) cold water was heated by mantle heat, and (3) hot water was stored in sandstone/siltstone, forming a sandstone geothermal reservoir with a temperature of ~70 ℃. These results have important guiding significance for the scientific exploration of geothermal resources in Northeast China.