铅锌银尾矿区土壤微生物活性及其群落功能多样性研究

通过对浙江省天台铅锌银尾矿区土壤微生物活性指标以及微生物群落功能多样性研究 ,结果表明 ,尾矿污染区土壤几种重金属含量比非矿区土壤有明显的增加。尾矿区土壤微生物特征发生了显著的变化 ,微生物生物量和可培养细菌数量显著降低 ,但土壤基础呼吸和微生物代谢商 (qCO2 )值却明显升高。Bi olog测试结果显示 ,随着重金属污染程度的加剧其土壤微生物群落结构发生了相应变化 ,尾矿区土壤微生物群落代谢剖面 (AWCD)及群落丰富度、多样性指数均显著低于非矿区土壤 ,且供试土壤间均达极显著水平差异 (p <0 .0 1) ,表明尾矿区重金属污染引起了土壤微生物群落功能多样性的下降 ,减少了能利用有关碳源底物的微生物数量。

Screening of Preprocessing Method of Biolog for Soil Microbial Community Functional Diversity

As one of the main methods of microbial community functional diversity measurement, biolog method was favored by many researchers for its simple oper- ation, high sensitivity, strong resolution and rich data. But the preprocessing meth- ods reported in the literatures were not the same. In order to screen the best pre- processing method, this paper took three typical treatments to explore the effect of different preprocessing methods on soil microbial community functional diversity. The results showed that, method B＇s overall trend of AWCD values was better than A and C＇s. Method B＇s microbial utilization of six carbon sources was higher, and the result was relatively stable. The Simpson index, Shannon richness index and Car- bon source utilization richness index of the two treatments were B〉C〉A, while the Mclntosh index and Shannon evenness were not very stable, but the difference of variance analysis was not significant, and the method B was always with a smallest variance. Method B＇s principal component analysis was better than A and C＇s. In a word, the method using 250 r/min shaking for 30 minutes and cultivating at 28 ℃ was the best one, because it was simple, convenient, and with good repeatability.

Geochip-based analysis of microbial functional genes diversity in rutile bio-desilication reactor

Biological desilication process is an effective way to remove silicate from rutile so that high purity rutile could be obtained. However, little is known about the molecular mechanism of this process. In this work, a newly developed rutile bio-desilication reactor was applied to enrich rutile from rough rutile concentrate obtained from Nanzhao rutile mine and a comprehensive high through-put functional gene array(Geo Chip 4.0) was used to analyze the functional gene diversity, structure and metabolic potential of microbial communities in the biological desilication reactor. The results show that TiO2 grade of the rutile concentrate could increase from 78.21% to above 90% and the recovery rate could reach to 96% or more in 8-12 d. The results also show that almost all the key functional genes involved in the geochemical cycling process, totally 4324 and 4983 functional microorganism genes, are detected in the liquid and ore surface, respectively. There are totally 712 and 831 functional genes involved in nitrogen cycling for liquid and ore surface samples, respectively. The relative abundance of functional genes involved in the phosphorus and sulfur cycling is higher in the ore surface than liquid. These results indicate that nitrogen, phosphorus and sulfur cycling are also present in the desiliconization process of rutile. Acetogenesis genes are detected in the liquid and ore surface, which indicates that the desiliconizing process mainly depends on the function of acetic acid and other organic acids. Four silicon transporting genes are also detected in the sample, which proves that the bacteria have the potential to transfer silicon in the molecule level. It is shown that bio-desilication is an effective and environmental-friendly way for enrichment of rough rutile concentrate and presents an overview of functional diversity and structure of desilication microbial communities, which also provides insights into our understanding of metabolic potential in biological desilication reactor ecosystems.

Functional genomic analysis of Hawaii marine metagenomes

Using high-throughput sequencing on metagenome to analyze marine microbial community, it is one of current main issues in the field of environmental microbe research. In this paper, we conducted the functional analysis on seven samples of metagenomic data from different depth seawater in Hawaii. The results of gene prediction and function annotation indicate that there are large amounts of potential novel genes of which functions remain unknown at present. Based on the gene annotation, codon usage bias is studied on ribosomal protein-related genes and shows an evident influence by the marine extreme environment. Furthermore, focusing on the marine environmental differences such as light intensity, dissolved oxygen, temperature and pressure among various depths, comparative analysis is carried out on related genes and metabolic pathways. Thus, the understanding as well as new insights into the correlation between marine environment and microbes are proposed at molecular level. Therefore, the studies herein afford a clue to reveal the special living strategies of microbial community from sea surface to deep sea.

Metagenome-based analysis:A promising direction for plankton ecological studies

The plankton community plays an especially important role in the functioning of aquatic ecosystems and also in biogeochemical cycles. Since the beginning of marine research expeditions in the 1870s, an enormous number of planktonic organisms have been described and studied. Plankton investigation has become one of the most important areas of aquatic ecological study, as well as a crucial component of aquatic environmental evaluation. Nonetheless, traditional investigations have mainly focused on morphospecies composition, abundances and dynamics, which primarily depend on morphological identification and counting under microscopes. However, for many species/groups, with few readily observable characteristics, morphological identification and counting have historically been a difficult task. Over the past decades, microbiologists have endeavored to apply and extend molecular techniques to address questions in microbial ecology. These culture-independent studies have generated new insights into microbial ecology. One such strategy, metagenome-based analysis, has also proved to be a powerful tool for plankton research. This mini-review presents a brief history of plankton research using morphological and metagenome-based approaches and the potential applications and further directions of metagenomic analyses in plankton ecological studies are discussed. The use of metagenome-based approaches for plankton ecological study in aquatic ecosystems is encouraged.

Seasonality regulates the effects of resource addition on plant diversity and ecosystem functioning in semi-arid grassland

Aims Seasonal variations in species richness,aboveground net primary productivity(ANPP)and stability under resource enrichment are frequently ignored.This study explores how the impacts of resource enrichment on species richness,ANPP and stability vary among seasons in semi-arid grasslands.Methods We conducted a 3-year experiment in an Inner Mongolia grassland to determine the effects of resource input(water[W],nitrogen[N])on species richness,community ANPP and stability using seasonal sampling during the growing season(2013–2015).Structural equation modeling(SEM)was used to examine the relative importance of resource input on community stability via mechanistic pathways in each month and the whole growing season.Important Findings Resource inputs did not affect community ANPP in May and June,while N and/or NW enhanced ANPP in July and August.Resource inputs generally did not affect species richness,asynchrony or community stability in most of the time.Positive responses of perennial bunchgrasses(PB)to N and/or NW treatments contributed to the increased community ANPP in July and August.Species asynchrony may be the major mechanism contributing to community stability in May and June and the entire growing season,and PB stability is potentially the primary factor controlling community stability in July and August under resource enrichment.Our results indicate that season and resource availability could interact to regulate species richness,community ANPP and stability in semi-arid grasslands.These findings have important implications for management practices in semi-arid grasslands in order to mitigate the impact of land use and global change.