The Deepest Known Ocean Virus Lives Under 29,000 Feet of Water

Credits: 2016 Deepwater Exploration of the Marianas. NOAA

Researchers specializing in marine virology have identified a unique virus thriving in the profoundly dark depths of the Mariana Trench, positioned over 29,000 feet beneath the sea.

A study released on September 20 in Microbiology Spectrum asserts that this is the most profound bacteriophage—viruses that prey on and multiply within bacteria—ever identified.

This vast chasm, situated in the western Pacific Ocean near Guam, reaches depths of over 36,000 feet at its deepest point and belongs to the hadal zone. Such zones derive their name from Hades, the ancient Greek deity of the netherworld, because of their deep troughs and significant pressures.

The carbon deposits at these hadal zone trenches might play a role in controlling the planet’s climate and carbon dynamics. Even amidst the severe pressures, frigid temperatures, and utter darkness, organisms persist. Explorers have found creatures such as fish, shrimp, and an array of microbes there.

This ecosystem contains its own checks and balances. The recently discovered phage targets bacteria from the Halomonas phylum. These bacteria are often present in the ocean’s deep sediment layers and around seafloor spouts that eject hot streams termed hydrothermal vents.

In this research, Wang, alongside a diverse team of experts, details the new virus, named vB_HmeY_H4907. Sediments, sourced from around 5.5 miles or over 29,000 feet below, harbored this virus, categorized as a bacteriophage.

These bacteriophages, also termed phages, invade and multiply within bacteria and are thought to be the planet’s most populous organisms.

Wang’s evaluation of the virus’s genetic data hints at an undiscovered viral lineage residing in deep-sea environments and offers fresh perspectives on the evolutionary history, genetic variance, and genomic characteristics of these deep-sea phages and their interplay with host organisms.

Earlier, this group employed metagenomic techniques to probe viruses targeting bacteria from the Oceanospirallales order. This category encompasses Halomonas, the phylum attacked by the newfound virus.

For this current analysis, the researchers hunted for viruses within bacterial samples gathered by marine virologist Yu-Zhong Zhang from Ocean University of China. Genomic scrutiny of this novel virus indicates its structural resemblance to its host and suggests it’s widespread across marine environments.

It’s also characterized as lysogenic, implying it infiltrates and multiplies within its host without typically terminating the bacterial entity. The viral DNA subsequently replicates as the cells split.

This revelation raises intriguing queries about the survival tactics employed by viruses in extreme, often isolated terrains like the Hadal zone trenches and their simultaneous evolution alongside their hosts.

Upcoming research will delve into the intricate dynamics of interactions between these abyssal viruses and their host organisms.