Diversity Of Bacteria In Biological Soil Crusts Growing On Wastelands Of Copper Mine Tailings, Tongling

Existing and smelting of mine will produce lots of mining waste that not only occupy large tracts of land, but also affected the functions of ecological and environmental.There were many wastelands of copper mine tailings in Tongling, Anhui Province. Most of the wastelands were in the natural ecological restoration. And the natural ecological restoration of wastelands was a typical primary succession.After the disposal, the tailings wastelands firstly came into being biological crusts, which is dominated by algae and moss, then herbaceous vascular plants settle down and gradually form a natural plant community.Biological soil crust, a consortium of algal, bacteria, fungi, lichen, moss, widely distributes in aird and semi-arid ecosystems. The crusts are important for the stability and restoration of ecosystems. At present, studies reported at home and abroad about the function of crusts in the ecosystems development of heavy metal mine tailings wastelands are uncommon.In this study, three types of biological soil crusts (algal crust, algal-moss crust and moss crust) living between different plant communities from two wastelands of copper mine tailings (Tongguanshan and Yangshanchong)ware collected. The physico-chemical properties and biological properties of substrate were analyzed. The diversities and composition of bacteria (Cyanobacteria, Nitrogen-fixing bacteria, Phototrophic bacteria) in the crusts were dicussed by the methods of PCR-DGGE and sequencing. The effect of biological soil crusts in the ecological restoration of tailings was investigated.The main results are as follows:1. The crusts could significantly improve the water content and Organic matter, total nitrogen, Available N. total Phosphorus, Available P of substrate; Compared to the bare tailings, pH values of substrate under the crusts ware lower.2. The bio-crusts could improved the soil microbial biomass carbon and nitrogen markedly; and could also improved the enzyme activities (Urease, Dehydrogenase. Catalase, Alkaline phosphatase) of siol.3. The specific 16S rRNA gene sequencing of Cyanobacteria showed that:The dominant cyanobacteria species growing in the bio-crusts are Microcoleus and Leptolyngbya.4. The specific nifH gene sequencing showed that: the dominant free nitrogen-fixing bacteria growing in bio-crusts are nitrogen-fixing cyanobacteria;5. The specific 16S rRNA gene sequencing of Phototrophic Bacteria showed that: The Phototrophic Bacteria growing in bio-crusts are mainly Anoxygenic Phototrophic Bacteria including Sphingomonadales of Kaistobacter and Rhizobiales of Phyllobacterium, Methylobacterium, Sinorhizobium.