The PEG (Plankton Ecology Group) model predicts differences in phenology between eutrophic and oligotrophic lakes regarding the occurrence, timing and magnitude of annual chlorophyll maxima and minima. While these predictions have been tested between lakes, hardly any tests exist using long‐term data. We test these predictions using chlorophyll time‐series (1980–2019) from Lake Constance in which trophic status shifted from eutrophic to oligotrophic conditions. We show that oligotrophication subsequently resulted in reduction of the summer and spring blooms, and finally the loss of the clear‐water phase. In contrast to the PEG model the spring bloom was not delayed, but advanced with oligotrophication. Warming modified the seasonal patterns via advancing clear‐water timing. Oligotrophication did not only influence phenologies, but also the importance of independent variables driving phenologies. Thus, the decline of nutrients was the dominant factor in shaping the seasonal patterns of chlorophyll in Lake Constance during the last four decades.

中文翻译：

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从富营养向寡营养转变期间叶绿素a浓度物候的定性和定量变化

PEG（浮游生物生态组）模型预测富营养化和贫营养化湖泊之间在年度叶绿素最大值和最小值的出现、时间和幅度方面的物候差异。虽然这些预测已经在湖泊之间进行了测试，但几乎没有任何使用长期数据的测试。我们使用康斯坦茨湖的叶绿素时间序列（1980-2019）来测试这些预测，其中营养状态从富营养条件转变为贫营养条件。我们发现，寡营养化随后导致夏季和春季水华减少，并最终导致清水阶段的丧失。与 PEG 模型相反，春季开花并未延迟，而是因寡营养化而提前。变暖通过提前清水时间改变了季节模式。少营养化不仅影响物候，而且影响自变量驱动物候的重要性。因此，过去四十年来，营养物质的减少是塑造博登湖叶绿素季节性模式的主导因素。