长江口崇明东滩湿地微生物群落结构研究

Microbial Community Structure in the Chongming Eastern Wetland of the Yangtze Estuary

以长江口发育最完善的河口型滩涂湿地-崇明东滩湿地为对象,采用高通量测序平台和定量PCR技术对光滩区和植被区沉积物的微生物群落结构进行研究,考察滩涂湿地自然演替过程中微生物群落变化规律及其环境驱动机制。结果表明,植被区沉积物表层的细菌16S rRNA基因拷贝数为光滩区表层的6.4倍,其Chao1指数与土壤有机碳、总氮和铵态氮呈显著负相关。植被区和光滩区沉积物中相对丰度大于1%的微生物门类有12个,占到总微生物群落的87%~90%。在属水平上,与光滩湿地相比,植被区湿地中相对丰度发生显著变化的优势属(>0.1%)为25个,占到所有属的8.3%和所有优势属的64.1%;显著增加的优势属(>0.2%)为10个,其增幅范围为0.22%~1.39%;其中,植被区沉积物中以脱硫球菌属和硫杆菌属微生物增加占主导,Cylindrospermopsis属为特有属。冗余分析表明,绿弯菌门微生物对土壤TOC、TN和NO3-等较为敏感,而酸杆菌门和拟杆菌门微生物对SO2-4、EC值和pH值等敏感。

Soil samples from the Chongming eastern tidal flat were analyzed by high-throughput sequencing platform and quantitative PCR technology, microbial community change and environmental driving mechanism were investigated during the natural succession of the wetland. Results showed that the copy number of bacterial 16 S rRNA gene in the vegetation tidal flat was 6.4 times that in the bare tidal flat. The Chao1 index of bacteria in the two tidal flats was significantly and negatively correlated with soil total organic carbon(TOC), total nitrogen(TN) and ammonium nitrogen(NH+4-N). The bacteria(relative abundance > 1%) in the two tidal flats fell into 12 known Phyla, which accounted for87%-90% of the total microbial community. At the genus level, 25 dominant genera(> 0.1%) changed significantly in the surface layer of the high tidal flat compared to that of the low tidal flat, which accounted for 8.3% of the total genera and 64.1% of the total dominant genera. Among them, 10 dominant genera significantly increased by 0.22% ~1.39%. The vegetation tide flat with Cylindrospermopsis being the main unique genus, was dominated by increase of Desulfococcus and Thiobacillus genera. Redundancy analysis showed that the distribution of Chloroflexi was mainly controlled by TOC, TN and NO-3, while Acidobacteria and Bacteroidetes were controlled by SO2-4, EC and pH.