Abstract We investigated how the N:P ratio can shape the structure of picophytoplankton and Microcystis, which are abundant and widespread in eutrophic lakes. Unialgal culture and coculture batch experiments were conducted to study the growth and interspecific competition of Microcystis and two freshwater picophytoplankton species, Mychonastes and Synechococcus, with varying N:P ratios. The results showed that the Ks values of Mychonastes and Synechococcus were more than two times smaller than those of Microcystis, and their μmax values were much higher than those of Microcystis due to their small size. Our results also revealed that the N:P ratio is important for shaping phytoplankton community structure even under high nutrient conditions. The optimal N:P ratios are 64, 32, and 32 for Mychonastes, Microcystis, and Synechococcus, respectively. Thus, Mychonastes outcompeted Microcystis when the N:P ratio was higher than 64, while Microcystis and Synechococcus grew equally well under all of the N:P ratio levels, since they have the same optimal N:P ratio.

中文翻译：

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在营养丰富的条件下，N:P 比影响微囊藻与其微型浮游植物对应物 Mychonastes 和 Synechococcus 的竞争

摘要 我们研究了 N:P 比如何影响富营养化湖泊中丰富和广泛分布的微型浮游植物和微囊藻的结构。进行了单藻培养和共培养批次实验，以研究微囊藻和两种淡水微型浮游植物，Mychonastes 和 Synechococcus，具有不同的 N:P 比的生长和种间竞争。结果表明，Mychonastes和Synechococcus的Ks值比微囊藻小两倍以上，并且由于体积小，μmax值远高于微囊藻。我们的结果还表明，即使在高营养条件下，N:P 比率对于塑造浮游植物群落结构也很重要。Mychonastes、微囊藻和聚球藻的最佳 N:P 比分别为 64、32 和 32。