UC San Diego

Cryptophytes (class Cryptophyceae) are bi-flagellated eukaryotic protists with mixed nutritional modes and a cosmopolitan distribution in marine and freshwater environments. Here we present a survey of cryptophyte abundance at the Scripps Institution of Oceanography Pier and in San Diego Bay. From 2011 to 2017, cryptophytes were consistently present off the pier with significant biotic and abiotic interactions but no observable seasonality. Weekly to bi-weekly high-throughput sequencing in 2016 revealed 16 unique cryptophyte sequences, with clade 4 and particularly 2 species dominant, one of which appears to be phylogenetically novel. One high cell abundance bloom in 2016 appears to be monospecific in origin and the second may be driven by grazing on an influx of an atypical Synechococcus clade. In the San Diego Bay, tidal forces appear to cyclically concentrate cryptophyte abundance at choke points in its bathymetry. A clade 4 sequence not dominant off the pier in 2016 is dominant in the back bay.