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.