Data from: Metabarcoding and metabolome analyses of copepod grazing reveal feeding preference and linkage to metabolite classes in dynamic microbial plankton communities

In order to characterize copepod feeding in relation to microbial plankton community dynamics, we combined metabarcoding and metabolome analyses during a 22-day seawater mesocosm experiment. Nutrient amendment of mesocosms promoted the development of haptophyte (Phaeocystis pouchetii)- and diatom (Skeletonema marinoi)-dominated plankton communities in mesocosms, in which Calanus sp. copepods were incubated for 24 h in flow-through chambers to allow access to prey particles (<500 μm). Copepods and mesocosm water sampled six times spanning the experiment were analysed using metabarcoding, while intracellular metabolite profiles of mesocosm plankton communities were generated for all experimental days. Taxon-specific metabarcoding ratios (ratio of consumed prey to available prey in the surrounding seawater) revealed diverse and dynamic copepod feeding selection, with positive selection on large diatoms, heterotrophic nanoflagellates and fungi, while smaller phytoplankton, including P. pouchetii, were passively consumed or even negatively selected according to our indicator. Our analysis of the relationship between Calanus grazing ratios and intracellular metabolite profiles indicates the importance of carbohydrates and lipids in plankton succession and copepod–prey interactions. This molecular characterization of Calanus sp. grazing therefore provides new evidence for selective feeding in mixed plankton assemblages and corroborates previous findings that copepod grazing may be coupled to the developmental and metabolic stage of the entire prey community rather than to individual prey abundances.为了表征桡足类（copepod）的摄食行为与微型浮游生物群落动态之间的关联，我们在一项为期22天的海水围隔（seawater mesocosm）实验中，结合了元条形码（metabarcoding）与代谢组学分析手段。实验通过向围隔体系中添加营养盐，诱导形成了以定鞭金藻（haptophyte）普氏棕囊藻（Phaeocystis pouchetii）和硅藻（diatom）海洋骨条藻（Skeletonema marinoi）为优势类群的浮游生物群落；在此体系中，哲水蚤属（Calanus sp.）桡足类被置于流通式培养舱中孵育24小时，使其能够接触粒径小于500微米的猎物颗粒。本实验期间共采集6次桡足类与围隔水体样本，并通过元条形码技术开展分析；同时，我们为所有实验天数的围隔浮游生物群落生成了细胞内代谢物谱。类群特异性元条形码比值（即被摄食猎物与周围海水中可获取猎物的占比）分析结果显示，桡足类的摄食选择具有多样性与动态性：其对大型硅藻、异养鞭毛虫（heterotrophic nanoflagellates）与真菌表现出正向选择，而包括普氏棕囊藻在内的小型浮游植物则被被动摄食，甚至根据本研究的判定指标呈现负向选择。我们针对哲水蚤属的牧食比率与细胞内代谢物谱之间的关联开展的分析表明，碳水化合物与脂质在浮游生物演替以及桡足类-猎物互作过程中发挥着关键作用。因此，针对哲水蚤属牧食行为的这一分子表征，为混合浮游生物群落中的选择性摄食行为提供了全新的实验证据，并佐证了既往研究结论：桡足类的牧食作用可能与整个猎物群落的发育及代谢阶段紧密相关，而非仅取决于单一猎物物种的个体丰度。