Abstract In this study, the concept of phytoplankton functional groups was used to assess phytoplankton community structure in an attempt to better understand their spatial and seasonal variation in extremely alkaline Dali Nur Lake. Samples were collected for analysis during spring, summer and autumn for a period of two years. We identified 13 phytoplankton functional groups (Lo, S1, H1, P, C, MP, X3, Y, X2, W1, J, F, and T) among 37 species out of which 7 groups Lo, H1, P, C, MP, X2, and F were dominant. The biomass of phytoplankton functional groups in the Lake exhibited a strong seasonal variation with the highest biomass value observed in autumn and lowest in spring. Functional groups MP, P, and C were dominant in spring when the temperatures were very low. Groups H1 and X2 were the dominant in summer corresponding to higher temperatures. In autumn groups Lo and X2 were the dominant corresponding to high levels of total phosphorus (TP). Our study revealed that alkalinity, pH, arsenic, chemical oxygen demand, and TP are the most important physical–chemical variables structuring the phytoplankton functional groups in Dali Nur Lake. Functional groups Lo and X2 were mainly influenced by TP while groups MP and P flourished better under high conditions of arsenic. This study reveals the importance of physical–chemical variables in the spatial and seasonal gradient, in structuring phytoplankton functional groups, and consequently in the assessment of environmental status of the lake.

中文翻译：

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华北极端碱性大理努尔湖浮游植物功能群的时空变化

摘要 本研究利用浮游植物功能群的概念来评估浮游植物群落结构，以期更好地了解极碱性大理努尔湖浮游植物的空间和季节变化。在两年的春季、夏季和秋季收集样品进行分析。我们在 37 个物种中鉴定了 13 个浮游植物功能组（Lo、S1、H1、P、C、MP、X3、Y、X2、W1、J、F 和 T），其中 7 个组 Lo、H1、P、C、 MP、X2 和 F 占优势。湖泊浮游植物功能群生物量呈现强烈的季节性变化，秋季最高，春季最低。当温度非常低时，官能团 MP、P 和 C 在春季占主导地位。H1 和 X2 组在与较高温度相对应的夏季占主导地位。在秋季，Lo 和 X2 组占优势，对应于高水平的总磷 (TP)。我们的研究表明，碱度、pH、砷、化学需氧量和总磷是构成大理努尔湖浮游植物功能群的最重要的物理化学变量。Lo和X2官能团主要受TP的影响，而MP和P组在高砷条件下生长得更好。这项研究揭示了物理化学变量在空间和季节梯度、浮游植物功能群的结构以及湖泊环境状况评估中的重要性。和 TP 是构成大理努尔湖浮游植物功能群的最重要的物理化学变量。Lo和X2官能团主要受TP的影响，而MP和P组在高砷条件下生长得更好。这项研究揭示了物理化学变量在空间和季节梯度、浮游植物功能群的结构以及湖泊环境状况评估中的重要性。和 TP 是构成大理努尔湖浮游植物功能群的最重要的物理化学变量。Lo和X2官能团主要受TP的影响，而MP和P组在高砷条件下生长得更好。这项研究揭示了物理化学变量在空间和季节梯度、浮游植物功能群的结构以及湖泊环境状况评估中的重要性。