Uncovering a Decade of Ecological Change in Monterey Bay Through eDNA Metabarcoding

Environmental DNA (eDNA) metabarcoding has the capacity to detect a multiplicity of species and is beginning to be used to compare communities through time. Here we present data from samples taken monthly by ship from 2008-2018 at a single station within Monterey Bay, California, as part of an ongoing time series. These samples were analyzed by metabarcoding using primers amplifying three different genetic markers (18S rRNA, COI, and 12S rRNA) targeting a diverse array of organisms from microbial eukaryotes to zooplankton, fish and marine mammals. Within this dataset we observe clear seasonal trends that reflect well-known patterns within Monterey Bay, such as the inshore seasonal blooms of diatoms and dinoflagellates. We can also detect interannual shifts in community composition such as the shift in copepod community composition occurring with the beginning of anomalously high temperatures in 2014. By analyzing this time series of genetic and environmental data we can gain greater insight into how communities within Monterey Bay respond to varying physical parameters. This study also demonstrates the utility of eDNA metabarcoding in analyzing historical samples as well as in detecting community changes across a broad array of organisms.