Alkaline mine drainage drives stream sediment microbial community structure and function

Improving the assessment of ecosystem and wildlife health: microbiome as an early indicator

Human activities are causing dramatic declines in ecosystem health, compromising the functioning of the life-support system, economic activity, and animal and human health. In this context, monitoring the health of ecosystems and wildlife populations is crucial for determining ecological dynamics and assessing management interventions. A growing body of evidence indicates that microbiome provides a meaningful early indicator of ecosystem and wildlife health. Microbiome is ubiquitous and both environmental and host-associated microbiomes rapidly reflect anthropogenic disturbances. However, we still need to overcome current limitations such as nucleic acid degradation, sequencing depth, and the establishment of baseline data to maximize the potential of microbiome studies.

Culturable heterotrophic bacterial diversity study from an Indian lignite mine habitat

Diversity lifts the productivity of any ecosystem as all the species have a vital role to play that is present within the ecosystem. The characterization is essential to delve into the ecological functions of microbial communities and discover the type of microorganisms present within the ecosystem. As microbial diversity in ecosystems responds to environmental disturbances, it functions as a marker to indicate the change in such ecosystems. Mine ecology differs significantly from other habitats due to the presence of acidic runoff. This paper provides insight into the diversity of cultivable bacteria isolated from lignite mines located in south Gujarat. A total of 67 heterotrophic isolates were successfully cultivated from the collected solid and water samples of the Rajpardi and Tadkeshwar Lignite mine sites. The isolates were characterized morphologically and biochemically, and intra- and extracellular enzyme synthesis were studied. Moreover, the relative density and frequency of cultivated isolates from the samples were calculated. The similarity and evenness of the heterotrophic isolated were studied by calculating diversity indices such as Shannon and Simpson. Alpha diversity was calculated in PAST software to analyse the similarity between the selected two mine sites. This research also explored the relationship between the variance in heterotrophic microbial diversity and substrate utilization richness of the studied lignite mines of Gujarat.

Responses of microbial community to geochemical parameters on vertical depth in bioheap system of low-grade copper sulfide

Monitoring of the microbial community in bioleaching system is essential for control process parameters and enhance the leaching efficiency. Due to the difficulty of sampling, microbial distribution, community succession and bioleaching activity along the vertical depth of bioleaching heaps remain unresolved. This study investigated the geochemical parameters and microbial community structure along a depth profile in a bioleaching heap and leachate. 80 ore samples at different heap depths and 9 leaching solution samples from three bioheaps of Zijin Copper Mine were collected. Microbial composition, mineral types and geochemical parameters of these samples were analyzed by 16S rRNA high-throughput sequencing and a series of chemical measurement technologies. The results revealed that the pH, Cu, Fe and the total sulfur contents were the major factors shaping the composition of the microbial communities in the bioleaching system. The extent of mineral oxidation increased as the sample depth increases, followed by the increasing of sulfur oxidizers. The abundance of sulfur and iron oxidizers including members of Acidithiobacillus, Sulfobacillus and Acidiferrobacter were significantly higher in the leaching heap than in the leaching solution, meanwhile, they showed strong positive interactions with other members within the same genera and iron oxidizer Leptospirillum and Ferroplasma. Besides, Acidithiobacillus negatively interacted with heterotrophs such as Sphingobium, Exiguobacterium, Brevundimonas and so on. On the contrast, members of Leptospirillum and unclassified Archaea were significantly abundant in the leaching solution and revealed strong interactions with members of Thermoplasmatales. The main conclusion of this study, especially the leaching potential of microorganisms prevailing in bioheaps and their relationships with geochemical factors, provides theoretical guidance for future process design such as the control of processing parameters and microbial community in heap leaching.

Impacts of high-quality coal mine drainage recycling for replenishment of aquatic ecosystems in arid regions of China: Bacterial community responses

Coal mine water is usually recycled as supplementary water for aquatic ecosystems in arid and semiarid mining regions of China. To ensure ecosystem health, the coal mine water is rigorously treated using several processes, including reverse osmosis, to meet surface water quality standards. However, the potential environmental impacts of this management pattern on the ecological function of receiving water bodies are unclear. In this study, we built several microcosm water ecosystems to simulate the receiving water bodies. High-quality treated coal mine drainage was mixed into the model water bodies at different concentrations, and the sediment bacterial community response and functional changes were systematically investigated. The results showed that the high-quality coal mine drainage could still shape bacterial taxonomic diversity, community composition and structure, with a concentration threshold of approximately 50%. Moreover, both the Mantel test and the structural equation model indicated that the salinity fluctuation caused by the receiving of coal mine drainage was the primary factor shaping the bacterial communities. 10 core taxa in the molecular ecological network influenced by coal mine drainage were identified, with the most critical taxa being patescibacteria and g_Geothermobacter. Furthermore, the pathway of carbohydrate metabolism as well as signaling molecules and interactions was up-regulated, whereas amino acid metabolism showed the opposite trend. All results suggested that the complex physical-chemical and biochemical processes in water ecosystems may be affected by the coal mine drainage. The bacterial community response and underlying functional changes may accelerate internal nutrient cycling, which may have a potential impact on algal bloom outbreaks.

Coal Mining Activities Driving the Changes in Microbial Community and Hydrochemical Characteristics of Underground Mine Water

Coal mining can cause groundwater pollution, and microorganism may reflect/affect its hydrochemical characteristics, yet little is known about the microorganism's distribution characteristics and its influence on the formation and evolution of mine water quality in underground coal mines. Here, we investigated the hydrochemical characteristics and microbial communities of six typical zones in a typical North China coalfield. The results showed that hydrochemical compositions and microbial communities of the water samples displayed apparent zone-specific patterns. The microbial community diversity of the six zones followed the order of surface waters > coal roadways > water sumps ≈ rock roadways ≈ goafs > groundwater aquifers. The microbial communities corresponded to the redox sensitive indices' levels. Coal roadways and goafs were the critical zones of groundwater pollution prevention and control. During tunneling in the panel, pyrite was oxidized by sulfur-oxidizing bacteria leading to SO₄^2- increase. With the closure of the panel and formation of the goaf, SO₄^2- increased rapidly for a short period. However, with the time since goaf closure, sulfate-reducing bacteria (e.g., c_Thermodesulfovibrionia, Desulfobacterium_catecholicum, etc.) proportion increased significantly, leading to SO₄^2- concentration's decrease by 42% over 12 years, indicating the long-term closed goafs had a certain self-purification ability. These findings would benefit mine water pollution prevention and control by district.