Northern lakes are facing rapid environmental alterations—including warming, browning, and/or changes in nutrient concentrations—driven by climate change. These environmental changes can have profound impacts on the synthesis and trophic transfer of polyunsaturated fatty acids (PUFA), which are important biochemical molecules for consumer growth and reproduction. Zooplankton are a key trophic link between phytoplankton and fish, but their biochemical responses to environmental change are not well understood. In this study, we assess the trends in fatty acid (FA) composition of zooplankton taxa among 32 subarctic and temperate lakes across broad climate‐productivity and ecosystem size gradients. We found that genus‐level taxonomy explained most FA variability in zooplankton (54%), suggesting that environmental changes that alter the taxonomic composition also affect the FA composition of zooplankton communities. Furthermore, the FA responses and their underlying environmental drivers differed between cladocerans and copepods. Cladocerans, including widespread Bosmina spp. and Daphnia spp., showed pronounced responses across the climate‐productivity gradient, with abrupt declines in PUFA, particularly eicosapentaenoic acid and arachidonic acid in warmer, browner, and more eutrophic lakes. Conversely, calanoid copepods had high and relatively stable PUFA levels across the gradient. In addition, all zooplankton taxa increased in stearidonic acid levels in larger lakes where PUFA‐rich cryptophytes were more abundant. Overall, our results suggest that climate‐driven environmental alterations pose heterogeneous impacts on PUFA levels among zooplankton taxa, and that the negative impacts of climate warming are stronger for cladocerans, especially so in small lakes.

中文翻译：

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北部湖泊的浮游动物在气候生产力和生态系统规模梯度上表现出脂肪酸的分类特异性反应

北部湖泊正面临着由气候变化驱动的快速环境变化，包括变暖、褐变和/或养分浓度变化。这些环境变化会对多不饱和脂肪酸（PUFA）的合成和营养转移产生深远的影响，而PUFA是消费者生长和繁殖的重要生化分子。浮游动物是浮游植物和鱼类之间的关键营养联系，但它们对环境变化的生化反应尚不清楚。在这项研究中，我们评估了 32 个亚北极和温带湖泊中浮游动物类群脂肪酸 (FA) 组成的趋势，这些湖泊跨越了广泛的气候生产力和生态系统规模梯度。我们发现属级分类学解释了浮游动物的大部分 FA 变异（54%），这表明改变分类组成的环境变化也会影响浮游动物群落的 FA 组成。此外，枝角类动物和桡足类动物的 FA 反应及其潜在的环境驱动因素也不同。枝角类动物，包括分布广泛的博斯米纳种。和水蚤spp.在整个气候生产力梯度上表现出明显的反应，PUFA突然下降，特别是在温暖、棕色和富营养化的湖泊中二十碳五烯酸和花生四烯酸。相反，桡足类桡足类在整个梯度上具有较高且相对稳定的 PUFA 水平。此外，在富含 PUFA 的隐植物更为丰富的较大湖泊中，所有浮游动物类群的十八碳四烯酸水平均有所增加。总体而言，我们的结果表明，气候驱动的环境变化对浮游动物类群中的多不饱和脂肪酸水平产生异质性影响，并且气候变暖对枝角类动物的负面影响更大，尤其是在小湖泊中。