Spatio-temporal patterns of phytoplankton communities and their driving environmental factors in Lake Qinghai

为了解青海湖浮游植物群落结构特征、时空分布格局及其关键环境驱动因子,于2020年5月(春)、8月(夏)、10月(秋)对青海湖进行系统调查,分析浮游植物群落在3个季度和4个区域(湖滨带、进水区、浅水区和深水区)间的差异。3次调查共检出浮游植物6门39属65种,物种组成以硅藻(36种,占总物种数的55.38%)、绿藻(17种,26.15%)和蓝藻(7种,10.76%)为主。4个区域间的浮游植物丰度存在显著差别,其中深水区丰度显著高于其他区域,主要原因可能在于深水区的环境较为稳定。3个季节间,浮游植物丰度和生物量具有较大差异:夏季和秋季的丰度、生物量均为春季的近10倍;浮游植物的优势类群和种类也发生了较大的变化:春季最具优势类群为硅藻门,优势种也主要隶属于硅藻门,而夏、秋两季则以蓝藻门种属占据主要优势。春季浮游植物的Pielou均匀度和Simpson多样性指数显著高于夏、秋两季,秋季Margalef指数和Shannon-Wiener多样性指数高于夏季。PERMANOVA分析和NMDS分析显示,青海湖浮游植物群落结构在不同区域和不同季节间具有显著差异。此外,dbRDA分析表明:盐度、水温和总磷是影响青海湖浮游植物分布的关键环境因子。与历史调查结果相比,青海湖浮游植物丰度出现数量级程度的上升,主要优势类群由硅藻门逐渐演变为蓝藻门。本研究揭示了青海湖浮游植物群落的时空分布特征及驱动因素,可为后续青海湖保护和管理提供理论支撑。;To understand the spatio-temporal of phytoplankton communities and their key environmental drivers in Lake Qinghai, we conducted a systematic survey during May (Spring), August (Summer), October (Autumn) 2020, examined how varied among three seasons four regions (lakeshore zone, inlet shallow deep zone). A total 65 species belonging to 39 genera 6 phyla were identified, with Bacillariophyta (36 species, accounting for 55.38% species) being species-richest class, followed by Chlorophyta (17 26.15%), Cyanophyta (7 10.76%). The abundance differed significantly regions, higher values zone than other zones, probably due more stable environment zone. There also significant differences biomass seasons. summer autumn nearly 10 times those spring, dominant groups changed greatly. most class Spring was Bacillariophyta, belonged while group Summer Autumn became its subset species. Pielou's evenness Simpson diversity indices Autumn, Margalef Shannon-Wiener showed Summer. PERMANOVA NMDS both indicated that structure different Qinghai. In addition, dbRDA analysis salinity, water temperature phosphorus factors affecting patterns Compared historical surveys, this study main community Qinghai gradually from Cyanophyta. This reveals pattern driving which can provide theoretical support subsequent protection management