Marine bacterioplankton play globally crucial roles in net remineralization of organic into inorganic compounds, and consume around 50 % of phytoplankton production. Bacterioplankton production is enhanced in regions of elevated productivity, especially in upwelling zones, where inorganic nutrients fuel phytoplankton production several fold higher than in surrounding areas. The equatorial Pacific Ocean experiences upwelling causing enhanced rates of particulate primary production in surface waters in the region from ~12dN to ~12dS compared to the surrounding oligotrophic tropical waters. The enhanced primary production has strong impacts upon net bacterioplankton production, with higher rates than in surrounding waters. Moreover, bacterioplankton production is linked to the supply of organic matter rather than temperature in these waters. Thus, the equatorial Pacific Ocean is an ideal location for examining the influence of variable organic matter quantity upon activities of tropical surface water microorganisms. The distribution of microbial assemblages and the genes they harbor has not been previously investigated in the region. Metagenomic studies of marine bacterioplankton along a transect from eastern North America to the Galapagos Islands (Rusch et al., 2007) has revealed variability in the genomic composition of bacterioplankton at scales < 200 km, and revealed that distinct suites of genes occur in distinct habitat types. To understand the relationship between microbial assemblage compostion, function, and habitat variability, a random shotgun sequencing (metagenomic) approach was applied to surface water microbial community samples from the 5 - 0.2 micron size fraction taken at 7 locations between Fiji and Hawaii on board the Centre for Microbial Oceanography: Research and Eduction - Biological Oceanography of the Upper Ocean: Latitudinal Assessment (CMORE-BULA) cruise. The samples range from the South Pacific Subtropical Gyre, across the region of equatorial upwelling, into the North Pacific subtropical gyre. In addition to samples in the 5 - 0.2 micron size fraction, and equatorial sample in the > 5 micron size fraction was also sequenced.
Marine Bacterioplankton Metagenomes
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