UC San Diego

Molecular methods are becoming increasingly popular in the field of microbial ecology for the characterization of phytoplankton communities at the taxonomic level. However, many techniques lack the potential for large scale spatiotemporal studies due to limitations in their methodology. In this study, a high-throughput, rapid and cost effective hybridization-based bead assay was applied to two sets of samples : (1) a yearlong time series (March 2009-2010) of surface seawater samples taken off the Scripps Pier, and (2) a three month long series of samples taken during a Lingulodinium polyhedrum bloom in June 2010. The presence and abundance of seven phytoplankton taxa known to occur in the La Jolla, CA coastal water community were measured using taxon-specific probes, and results showed significant temporal variability throughout the sampling period. The diatoms Chaetoceros and Cylindrotheca and the dinoflagellate taxa Prorocentrum and Scrippsiella exhibited similar temporal abundances, suggesting that commonalities in traits allow for the coexistence of these phylogenetically divergent taxa. The dinoflagellates Akashiwo and Lingulodinium also shared similar peak distributions during the bloom following peak abundances of diatoms in early spring, indicating biological succession of these taxa. Our study demonstrated the potential application of the Luminex bead array assay as a valuable tool to assess phytoplankton community dynamics. Further analyses of the ecological strategies of the seven taxa are necessary for a more comprehensive evaluation of the biotic and abiotic factors structuring phytoplankton communities