Stable carbon isotope data for thirteen individual amino acids from twelve species of eukaryotic microalgae and four species of eukaryotic microalgae

Using controlled cultures, this project characterized the amino acid carbon isotope fingerprints — a multivariate metric of amino acid carbon isotope values — of twelve different species of eukayrotic microalgae from four major Classes of eukaryotic microalgae: diatoms, dinoflagellates, raphidophytes, and prasinophytes (three species per Class). Phytoplankton cultures were generated from established laboratory culture lines in the URI microalgal libraries and the National Center for Marine Algae and Microbiota (NCMA; formerly CCMP). This dataset includes stable carbon isotope data for thirteen individual amino acids from all twelve species of eukaryotic microalgae grown at 20° Celsius (C) and four species of eukaryotic microalgae (one from each of the four Classes) raised at 15°C, 20°C, and 25°C. Cultures were grown in triplicate for each species and temperature treatment under highly constrained growth conditions. These amino acid carbon isotope data were used to identify primary producers at the base of food webs supporting consumers in two contrasting systems from published literature: 1) penguins feeding in a diatom-based food web (McMahon et al. 2015 Ecology and Evolution 5:1278–1290) and 2) mixotrophic corals receiving amino acids directly from autotrophic endosymbiotic dinoflagellates and indirectly from water column diatoms, prasinophytes, and cyanobacteria, likely via heterotrophic feeding on zooplankton (Fox et al. 2019 Functional Ecology 33:2203-2214). The increased taxonomic specificity of CSIA-AA (Compound-Specific Isotope Analysis of Amino Acids) fingerprints developed here will greatly improve future efforts to reconstruct the contribution of diverse eukaryotic microalgae to the sources and cycling of organic matter in food web dynamics and biogeochemical cycling studies.本研究通过可控培养体系，对隶属于真核微藻四大主要类群（硅藻、甲藻、针胞藻、青绿藻，每类群各3个物种）的12种真核微藻的氨基酸碳同位素指纹特征——即氨基酸碳同位素值的多变量综合指标——进行了系统表征。所有浮游藻培养物均源自URI微藻库及美国国家海洋藻类与微生物培养物中心（NCMA，前身为CCMP）的已建立实验室培养株系。 本数据集包含两类培养样品的稳定碳同位素数据：其一为12种真核微藻在20℃条件下培养得到的13种单体氨基酸的同位素数据；其二为四大类群各1个物种，分别在15℃、20℃、25℃三个温度梯度下培养得到的对应数据。所有物种及温度处理组的培养均设置三次生物学重复，培养条件严格受控。本研究利用这些氨基酸碳同位素数据，结合已发表文献中的两类典型生态系统，对支撑消费者的食物网基底初级生产者进行了溯源：1）以硅藻为基础食物网的企鹅种群（McMahon等，2015 "Ecology and Evolution", 5:1278–1290）；2）混合营养型珊瑚，其氨基酸既直接来自自养共生甲藻，又间接通过浮游动物异养摄食获取水柱中的硅藻、青绿藻及蓝细菌（Fox等，2019 "Functional Ecology", 33:2203-2214）。 本研究构建的氨基酸化合物特异性同位素分析（CSIA-AA，Compound-Specific Isotope Analysis of Amino Acids）指纹图谱，其分类学分辨率得到显著提升，将极大助力未来研究：在食物网动态及生物地球化学循环研究中，更精准地重构多样真核微藻在有机质来源与循环中的贡献。