Marine Microbial Phylogenetic Diversity in the Equatorial Pacific
Jeremy S. Huang
Mentor: Adam Martiny
The marine cyanobacteria are an abundant and diverse family, intrinsic in global ocean cycling as primary
producers. As such, it is important to identify the variability of its members across environments to better
understand their potential contributions to a changing ocean. In this study, we investigate the gene content
diversity of marine cyanobacteria in the Equatorial Pacific across varying depths and latitudes. Seawater
samples were taken along a latitudinal nutrient gradient from Hawaii to the Equator at varying depths that
included oxygen minimum zones. Microbial diversity was measured by extracting the DNA of seawater
samples and sequencing an amplified portion of the RNA polymerase gene (rpoC1). High-throughput
sequencing was used on the amplified rpoC1 sequences and genetic analysis of the sequences revealed the
presence of several ecotypes and strains of Prochlorococcus and Synechococcus, two of the most abundant marine
cyanobacteria. The distribution of these strains varied both due to depth and along a latitudinal gradient.
Depth was found to be a strong factor in microbial diversity, but latitudinal changes contributed to an even
greater diversification as samples reached closer to the equator.