Abstract

As major primary producers in aquatic systems, the diversity and community composition dynamics of photosynthetic picoeukaryotes (PPEs) have been investigated in recent years. Here, we explored the three-day diurnal succession of the PPE community in a highly eutrophic lake in early spring using a combination of flow cytometric sorting and high-throughput sequencing. Our results showed that the PPEs were the dominant group of autotrophic picophytoplankton, although they had relatively low diversity and were dominated by the Stephanodiscaceae family in early spring in Lake Taihu. Furthermore, PPE abundance was significantly higher at night than during the day, probably due to their high specific rate of carbon uptake during the day and rapid proliferation at night. Several environmental variables had a significant influence on the PPE community composition, and the daily effect was more important than the diurnal effect when shaping the PPE community in Lake Taihu at a temporal scale of three days. Furthermore, based on the variation partitioning analysis (VPA), the relative importance of abiotic factors (deterministic processes) to short-term succession was low, explaining only 20.44%of the PPE community variation. We therefore conclude that stochastic processes determined PPE community assembly over a short temporal scale based on a neutral community model (NCM).

中文翻译：

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在小时间尺度塑造太湖光合微核生物（PPEs）群落时，日效应比日效应更重要

摘要

作为水生系统的主要初级生产者，近年来研究了光合微核生物 (PPE) 的多样性和群落组成动态。在这里，我们结合流式细胞仪分选和高通量测序，探索了早春高度富营养化湖泊中 PPE 群落的三天昼夜演替规律。我们的研究结果表明，PPEs 是自养微型浮游植物的优势群，尽管它们的多样性相对较低，并且在太湖早春以千金藤科为主。此外，PPE 的丰度在夜间显着高于白天，这可能是由于它们在白天的高比碳吸收率和在夜间的快速增殖。几个环境变量对PPE群落组成有显着影响，在3天的时间尺度上塑造太湖PPE群落时，日效应比日效应更重要。此外，基于变异分区分析 (VPA)，非生物因素（确定性过程）对短期演替的相对重要性较低，仅解释了 PPE 群落变异的 20.44%。因此，我们得出结论，随机过程基于中性社区模型（NCM）在短时间内确定了 PPE 社区组装。非生物因素（确定性过程）对短期演替的相对重要性较低，仅解释了 PPE 群落变异的 20.44%。因此，我们得出结论，随机过程基于中性社区模型（NCM）在短时间内确定了 PPE 社区组装。非生物因素（确定性过程）对短期演替的相对重要性较低，仅解释了 PPE 群落变异的 20.44%。因此，我们得出结论，随机过程基于中性社区模型（NCM）在短时间内确定了 PPE 社区组装。