Characterizing Viral Populations in the New Zealand Chatham Rise

Background & Question 
The ocean is estimated to contain 10 to the 30 viruses(1) , making them the most abundant biological entities in aquatic ecosystems(2). Relatively little is known about marine viruses, and most viral populations discovered are novel. Virus-host interactions play a key role in ocean biogeochemistry with 20% of marine bacteria lysed daily by viruses(3). Additionally, some viruses harbor auxiliary metabolic genes that can modulate their host’s metabolism and impact carbon, nitrogen, and sulfur cycling(4). While microbial populations can impact the environment, environmental conditions also influence microbial composition. Prokaryotic genomes have been shown to be affected by environmental factors. Microbial genomes exhibit higher GC content in waters with higher amounts of phosphate and nitrate, and lower temperatures, salinity, and oxygen levels(5). Viruses are closely tied to their hosts, having shown to be synchronized with microbial processes in the surface layer of the ocean(6), but the relationship between environmental factors and viral genomic composition remains to be elucidated. In addition, viral diversity, reproductive strategies, and auxiliary metabolic genes have been shown to vary with available nutrients and depth(7).