西藏湖泊表层沉积物硅藻组合及其环境影响因素  

Modern diatom combination characters and an influence factor analysis of the surface sediment of lakes in Tibet

作　　者：胡晓兰[1] 王彩红[1] 任雅琴[1] 李瑞博[1] 张成君[2] 

机构地区：[1]兰州大学资源环境学院,兰州730000 [2]兰州大学地质科学与矿产资源学院,兰州730000

出　　处：《兰州大学学报（自然科学版）》2014年第4期455-464,共10页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金项目(41173015);高等学校博士学科点专项科研基金项目(20100211110020)

摘　　要：通过对西藏20个不同类型湖泊表层沉积物中硅藻属种分析鉴定,共发现10科27属212种硅藻,以喜碱性硅藻为主.其中相对优势属为Navicula(17.5%),Nitzschia(10.8%),Cymbella(8.5%),Fragilaria(8.5%),Gomphonema(7.1%),Pinnularia(6.1%);相对优势种为Denticula elegans,Fragilaria pinnata,Nitzschia denticula,其次为Navicula cincta var.leptocephala,Fragilaria leptostauron var.martyi,Amphora ovalis var.pediculus.研究表明:盐度指标T DS,SC,ρ(Mg2+),ρ(Mg2+)/ρ(Ca2+),ρ(CO2-3+HCO-3)和碱度是藏北湖泊硅藻分布的主控因素,pH值对硅藻种属组合特征也有明显控制作用.Denticula elegans可在电导率为3.98 mS/cm的环境中良好生长;Nitzschia denticula在西藏地区对pH的最高适应值达10.56;Fragilaria pinnata最优生长环境pH值为8.68,电导率为0.30 mS/cm;Fragilaria leptostauron var.martyi对盐度有一定的耐受能力,可在SC最高达3.98 mS/cm的环境中生长;Amphora ovalis var.pediculus在西藏地区最适生长环境SC为0.48 mS/cm,pH值为10.26;微咸水种Amphora veneta具有较强的耐盐性,能在盐度为345 mg/L的环境中大量生长;Opephora martyi的大量生长可能指示了营养良好的水体环境.Diatom samples of the surface sediment from 20 lakes in Tibet were collected and analyzed. The results showed that the diatom communities include 10 families, 27 genera, 212 species, and the alkaliphilous species are dominating in the Tibet lakes. The dominate genera are Navicula（17.5%）, Nitzschia（10.8%）, Cymbella（8.5%）, Fragilaria（8.5%）, Gomphonema（7.1%） and Pinnularia（6.1%）; and the dominate species are Denticula elegans, Fragilaria pinnata and Nitzschia denticula. Navicula cincta var. leptocephala, Fragilaria leptostauron var. martyi and Amphora ovalis var. pediculus are found in these lakes also. Salinity proxies（T DS, SC,ρ（Mg2＋）, ρ（Mg2＋）/ρ（Ca2＋）, ρ（CO2-3＋HCO-3） and alkalinity are the main limit factors for the diatom distributions in the lakes in the northern part of the Qinghai-Tibet Plateau, and pH values control the diatom components in these lakes. Denticula elegans can grow well in lakes whose conductivity is 3.98 mS/cm, and the highest pH tolerance of Nitzschia denticula is 10.56. The optimal growth conditions for Fragilaria pinnata in Tibet are that pH is 8.68 and conductivity is 0.30 mS/cm. Fragilaria leptostauron var. martyi can grow under the conductivity lower than 3.98 mS/cm. Amphora ovalis var. pediculus grows well under the conductivity of0.48 mS/cm and pH 10.26. Amphora veneta is found with high abundance under a salinity（T DS） of 345 mg/L.The high abundance of Opephora martyi may indicate a rich nutritional environment of the lake.

关 键 词：表层沉积物 硅藻 环境因子 主成分分析 西藏湖泊 

分 类 号：X173[环境科学与工程—环境科学]