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New virus discovered in the deepest part of the ocean

In a recent study, experts describe a new virus that was found in sediment dug up from the Mariana Trench, the world’s deepest oceanic chasm. The research team was led by marine virologist Dr. Min Wang from the Ocean University of China in Qingdao.

“Viruses play crucial roles in the ecosystem by modulating the host community structure, mediating biogeochemical cycles, and compensating for the metabolism of host cells,” wrote the study authors. 

Unique microorganisms 

Mariana Trench, the world’s deepest hadal habitat, harbors a variety of unique microorganisms that have adapted to its extreme conditions of low temperatures, high pressure, and nutrient scarcity. However, our knowledge about isolated hadal phage strains in the hadal trench is still limited.

Deepest known isolated phage

According to the researchers, the newly discovered virus targets bacteria that are usually found in deep ocean. 

Sourced from a depth of 8,900 meters in the trench, this bacteriophage stands as the “deepest known isolated phage in the global ocean,” said Wang.


Bacteriophages, or simply phages, are viruses that thrive by infecting and replicating inside of bacterial cells. Often overlooked, these phages are believed to outnumber any other life form on Earth. 

The virus targets the Halomonas bacteria, which are commonly associated with deep-sea sediment and hydrothermal vents – underwater geysers that spout heated water from the Earth’s crust.

Study implications 

Wang said the group’s analysis of the viral genetic material points to existence of a previously unknown viral family in the deep ocean, as well as new insights into the diversity, evolution and genomic features of deep-sea phages and phage-host interactions.

Focus of the study 

The study builds on previous research where metagenomic analysis was employed to delve into viruses that prey on bacteria, particularly those within the Oceanospirallales order, including Halomonas. 

For the analysis, the researchers collaborated closely with marine virologist Dr. Yu-Zhong Zhang, who focuses on microbial life in the world’s most extreme habitats. The experts looked for viruses in bacterial strains collected and isolated by Dr. Zhang’s tram.

What the researchers learned 

Interestingly, the genomic structure of the newly discovered virus, labeled as vB_HmeY_H4907, indicates its widespread presence in the oceans and reveals its symbiotic coexistence with its host. 

Unlike many viruses, this particular phage is lysogenic, meaning it typically doesn’t kill its bacterial host. Instead, as the bacteria multiply, so does the viral genetic material.

Future research 

With this discovery, Wang emphasized the need to further explore the interactions and survival strategies of viruses in these harsh, secluded realms. 

Wang said the group plans to investigate the molecular machinery that drives interactions between deep-sea viruses and their hosts. 

The researchers are also searching for other new viruses in extreme places, “which would contribute to broadening our comprehension of the virosphere,” Wang said. “Extreme environments offer optimal prospects for unearthing novel viruses.”

The study is published in the journal Microbiology Spectrum.

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