西藏五个盐湖浮游生物组成与微生物多样性

Planktonic Composition and Microbial Biodiversity in Five Salt Lakes in Tibet

西藏蕴藏着丰富的盐湖资源,为了调查西藏盐湖的生物资源多样性,分别于2019年9月和2020年7月对西藏那曲市和阿里地区的30个湖泊进行了调查.采集了当穹错、班戈错、洞错、聂尔错和盐湖乡5个盐湖(盐度为40~110)的水体和底泥样品,进行了湖水离子组成分析、浮游生物检测、底泥微生物多样性分析以及细菌的分离鉴定.所有盐湖水样中共检测到5门36属53种浮游植物(包含未定种),在洞错盐湖固定后的水样中除卤虫外还发现了5种其他的浮游动物(包括3种轮虫和2种桡足类动物).当穹错、班戈错、聂尔错的卤虫种群密度为3.1×10^(3)~6×10^(4) m^(-3),并且不同盐湖中无节幼体/后无节幼体/幼虫/成虫的比例和雌雄比例存在差异.高通量测序表明,盐湖底泥的微生物多样性与盐度成反比,其中盐度较低的洞错盐湖底泥的微生物多样性最高.典型关联分析表明,影响洞错盐湖底泥微生物多样性的主要因素是pH和盐度,而当穹错和班戈错盐湖底泥的微生物多样性主要与碳酸盐和硫酸盐浓度相关.当穹错、盐湖乡、班戈错、聂尔错和洞错盐湖底泥微生物的优势属分别为碱扰菌属(Alkaliflexus,33.0%)、Salipaludibacillus(12.0%)、盐单胞菌属(Halomonas,9.0%)、粉色海生菌属(Roseimarinus,8.1%)和Izimaplasma(2.3%).从盐湖底泥样品中分离获得了28株嗜盐微生物,16S rDNA鉴定结果表明,其中20株属于变形菌门(Proteobacteria),13株属于盐单胞菌属.本研究提供了西藏盐湖生物资源的最新信息,旨在为西藏盐湖生物资源的开发利用奠定理论基础.

Tibet is rich in salt lake resources.To investigate the biodiversity in salt lakes,the surveys on 30 lakes located in Nagqu and Ngari region were conducted in September of 2019 and July of 2020.The water and sediment samples were collected from five salt lakes,namely Dangqiong Co,Bongo Co,Dong Co,Nier Co and Yanhu Lake(salinity 40-110),and analyzed for ionic composition,planktonic composition,microbial diversity of sediment and bacterial isolation and identification.Through investigation,a total of 53 phytoplankton species in 5 phyla and 36 genera(including undetermined species)were observed in all salt lake water samples.Besides Artemia,5 other zooplankton species(including 3 rotifer species and 2 copepod species)were also found in Dong Co.The Artemia population density in Dangqiong Co,Bongo Co and Nier Co ranged from 3.1×10^(3) m^(-3) to 6×10^(4) m^(-3).The proportion of nauplii/metanauplii/juveniles/adults and ratio of female/male were differed in different salt lakes.The high-throughput sequencing analysis showed that the microbial diversity of sediment was inversely proportional to water salinity,and the highest values were obtained in Dong Co.Canonical correlation analysis indicated that the biodiversity of Dong Co correlated to pH and salinity,while the content of carbonate and sulfate were the main factors influencing the biodiversity of Dangqiong Co and Bongo Co.The dominant genus were Alkaliflexus(33.0%),Salipaludibacillus(12.0%),Halomonas(9.0%),Roseimarinus(8.1%)and Izimaplasma(2.3%)in the sediments of Dangqiong Co,Yanhu Lake,Bongo Co,Nier Co and Dong Co,respectively.We isolated 28 strains of halophilic microorganisms from the sediment samples.16S rDNA identification results showed that the main phylum and genus were Proteobacteria(20 isolates)and Halomonas(13 isolates).Our survey has provided the latest information on microbial biodiversity,and phytoplanktonic composition and Artemia resources in Tibet salt lakes,and has laid a theoretical foundation for the exploration and utilization of biological resources in Tibet salt lakes.