| 土地利用影响下无定河流域浮游植物群落与环境因子响应 |
| 摘要点击 689 全文点击 93 投稿时间：2023-04-23 修订日期：2023-06-25 |
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| 中文关键词 无定河流域 浮游植物 土地利用 环境因子 结构方程模型（SEM） |
| 英文关键词 Wuding River Basin phytoplankton land use environmental factors structural equation modeling（SEM） |
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| 中文摘要 |
| 为探究不同土地利用类型影响下,无定河流域浮游植物群落特征变化及主要环境影响因子,于2021年春季（4~5月）和秋季（9~10月）对无定河干支流及典型淤地坝水体进行系统的水生态调查.共鉴定浮游植物273种,隶属于7门90属,春季（241种）高于秋季（189种）,春和秋两季浮游植物密度、生物量均值分别为479.95×104 cells·L-1、6.41 mg·L-1和171.29×104 cells·L-1、2.64 mg·L-1.流域优势种以硅藻门的梅尼小环藻（Cyclotella meneghiniana）、尖针杆藻（Synedra acus）、简单舟形藻（Navicula simples）和谷皮菱形藻（Nitzschia palea）为主,裸藻（Euglena spp.）为淤地坝水体特有优势种.Shannon-Wiener多样性指数和Margalef丰富度指数显示春季高于秋季,Pielou均匀度指数变化相对较小.采样点1000 m河岸带缓冲区土地利用类型以耕地和草地为主.环境因子中水温（WT）、浊度（Turb）、pH、溶解氧（DO）、总氮（TN）和总磷（TP）浓度时空变化显著.结构方程模型（SEM）表明：不同土地利用类型通过影响环境因子而间接影响浮游植物群落特征,春季影响浮游植物群落特征的主要环境因子是水温、流速、pH、溶解氧和氨氮（NH4+-N）,而在秋季是浊度、水温和溶解氧. |
| 英文摘要 |
| In order to investigate the changes in phytoplankton community characteristics and the main environmental impact factors in the Wuding River Basin under the influence of different land use types, a systematic aquatic ecological survey was conducted in the spring （April-May） and autumn （September-October） of 2021 on the main stream and tributaries of the Wuding River and typical check dam water bodies. A total of 273 phytoplankton species belonging to seven phyla and 90 genera were identified, with higher numbers in spring （241 species） than in autumn （189 species）. The mean values of phytoplankton density and biomass were 479.95×104 cells·L-1 and 6.41 mg·L-1 and 171.29×104 cells·L-1 and 2.64 mg·L-1 in spring and autumn, respectively. The dominant species in the basin were mainly Cyclotella meneghiniana, Synedra acus, Navicula simples, and Nitzschia palea, and Euglena spp. was the dominant species specific to the check dam water bodies. The Shannon-Wiener diversity index and Margalef richness index showed higher values in spring than in autumn and thter was relatively little variation in the Pielou evenness index. The land use types in the 1 000 m riparian zone buffer at the sampling site were mainly cultivated land and grassland. The temporal and spatial variations in water temperature （WT）, turbidity （Turb）, pH, dissolved oxygen （DO）, total nitrogen （TN）, and total phosphorus （TP） concentrations in environmental factors were significant. Structural equation modeling （SEM） showed that different land use types indirectly influenced phytoplankton community characteristics by affecting environmental factors, and the main environmental factors affecting phytoplankton community characteristics were WT, velocity of flow （v）, pH, DO, and ammonia nitrogen （NH4+-N） in spring, whereas Turb, WT, and DO were the main factors in autumn. |
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