Data from: Metabarcoding and metabolome analysis of copepod grazing reveals 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-hours in flow-through chambers to allow access to prey particles (< 500 µm). Copepods and mesocosm water sampled six times spanning the experiment were analyzed 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.

为表征桡足类（copepod）摄食与微型浮游生物群落动态的关联，我们在一项为期22天的海水围隔（mesocosm）实验中，联合采用元条形码（metabarcoding）与代谢组学（metabolome）分析手段。对围隔体系施加营养添加物后，促生了以定鞭金藻门（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；在该围隔体系中，哲水蚤属（Calanus sp.）桡足类被置于流水培养室（flow-through chambers）中孵育24小时，使其能够接触粒径小于500微米的猎物颗粒。本实验全程共开展6次采样，分别采集桡足类样本与围隔水体样本，采用元条形码技术进行分析；同时，我们在所有实验天数均完成了围隔浮游生物群落的细胞内代谢物谱（intracellular metabolite profiles）构建。类群特异性元条形码比率（即被摄食猎物与周围海水中可获得猎物的比值）结果显示，桡足类的摄食选择兼具多样性与动态性：其对大型硅藻、异养微型鞭毛虫（heterotrophic nanoflagellates）及真菌呈现正向选择，而包括普氏棕囊藻在内的小型浮游植物则多为被动摄食，甚至依据本研究的判定指标呈现负向选择。我们针对哲水蚤牧食比率（grazing ratios）与细胞内代谢物谱之间的关联展开分析，结果表明碳水化合物与脂质在浮游生物演替（plankton succession）及桡足类-猎物互作过程中具有关键意义。因此，对哲水蚤属（Calanus sp.）牧食行为的上述分子表征，为混合浮游生物群落中的选择性摄食提供了新的实验证据，并佐证了此前的研究结论：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相耦合，而非仅与单一猎物的种群丰度相关。