In the shallow eutrophic lakes in cold, arid regions, the phytoplankton functional groups and the factors that drive their spatiotemporal variabilities remain unclear. Samples were collected from Lake Ulansuhai in April, August, and October 2017 (wet season) and January 2018 (dry season). Based on the functional group classification method, 23 phytoplankton functional groups with 5 major ones were identified. During the wet season, high amounts of nutrients, elevated temperatures, and heavy rainfall produced spatiotemporal variabilities in phytoplankton communities, whereas during the dry season, the frozen period was the critical factor that determined the spatiotemporal variabilities in the phytoplankton communities. Through redundancy analyses, total nitrogen and total phosphorus concentrations were observed to directly affect the phytoplankton growth; algal growth affected the chemical oxygen demand, and pH and environmental factors interacted with the phytoplankton growth. These results highlight the complex feedbacks of shallow eutrophic lake ecosystems in arid regions. Group TC (represented by Lyngbya) was correlated with Huangtai algae. In August, a Huangtai algal bloom resulted in a relatively stable water column, which was conducive to group TC growth. Therefore, the presence of certain phytoplankton functional groups can indicate the current lake conditions by identifying the coverage of Huangtai algae, which provides a scientific basis for an early warning of a potential algal bloom.

中文翻译：

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寒冷干旱地区浅水富营养化湖泊中浮游植物功能群的时空变化。

在寒冷，干旱地区的浅水富营养化湖泊中，浮游植物功能群及其驱动因素的时空变异性尚不清楚。样品分别于2017年4月，8月和10月（湿季）和2018年1月（旱季）从乌兰苏海湖采集。基于功能群分类方法，确定了23个浮游植物功能群，其中5个主要功能群。在雨季，大量的养分，高温和强降雨在浮游植物群落中产生时空变异，而在旱季，冻结期是决定浮游植物群落时空变异的关键因素。通过冗余分析，观察到总氮和总磷浓度直接影响浮游植物的生长；藻类生长影响化学需氧量，pH和环境因素与浮游植物生长相互作用。这些结果突出了干旱地区浅水富营养化湖泊生态系统的复杂反馈。TC组（由代表Lyngbya）与黄台藻相关。8月，黄台海藻爆发导致水柱相对稳定，这有利于群体TC的生长。因此，某些浮游植物官能团的存在可以通过识别黄台藻的覆盖范围来指示当前的湖泊状况，这为潜在藻华的早期预警提供了科学依据。