Comparison of Advanced Methodologies for Phytoplankton Community Analysis

Emily Pierce1, Adrian Marchetti1, Astrid Schnetzer2, Olivia Torano1, Logan Whitehouse1 and Johnson Lin1, (1)University of North Carolina at Chapel Hill, Marine Sciences, Chapel Hill, NC, United States, (2)North Carolina State University, Marine, Earth, and Atmospheric Sciences, Raleigh, NC, United States
Phytoplankton composition has an important influence on ocean biogeochemical cycling. Developing effective methods for characterizing phytoplankton communities under different environmental conditions is vital to understanding their role in the carbon cycle. Two widely-used methods for identifying plankton that are experiencing recent rapid advancements are cell imaging and molecular sequencing. This project aims to compare protist species abundance and diversity results derived from both cell imaging and 18S rDNA sequencing in order to evaluate these methods for plankton community analysis. FlowCam imaging allows taxonomic identification via microscopy through semi-automated morphological characterization. Whereas, the amplicon sequencing method used in this study is dependent on the similarity of sequences obtained from the environment to known sequences within a reference database. Both methods were implemented in tandem to analyze samples collected on a recent field cruise within the California Upwelling Zone. Shifts in the phytoplankton community composition were detected following simulated upwelling in both iron-replete and iron-limited waters. Overall, our study provides an intercomparison across two highly evolving taxonomic approaches used to determine plankton species abundance and distributions in the ocean.