Far beneath the Pacific Ocean, Chinese researchers have uncovered a largely unknown ecosystem teeming with viruses, including “jumbo viruses.”
In a landmark study published in Nature Communications, marine scientists mapped the viral diversity of the Clarion-Clipperton Zone (CCZ), a 5.9-million-square-kilometer region of the Pacific Ocean that has become a major target for potential commercial deep-sea mining.
The research provides an unprecedented biological baseline for an abyssal environment facing potential industrial disturbance, revealing that more than 99% of the viral species identified in the region were previously unknown to science.
WHAT IS THE CCZ?
The Clarion-Clipperton Zone, located in the Pacific Ocean between Hawaii and Mexico, is known for its vast seafloor fields of polymetallic nodules. These potato-sized mineral deposits are rich in nickel, copper, cobalt, and manganese.
As mining companies eye these deposits for minerals used in batteries and other technologies, environmental researchers are racing to document the fragile ecosystems thriving around them.
Researchers from Chongqing University and the Second Institute of Oceanography used metagenomic sequencing to analyze sediment core samples collected from 14 oceanographic stations across the region, allowing them to examine the largely unexplored viral communities of the deep sea.
UNKNOWN TO SCIENCE: OVER 11,000 VIRUSES IN THE DEEP
The researchers identified 11,742 viral operational taxonomic units, representing distinct species-level groups of viral genomes.
More than 99% showed no taxonomic match with existing databases, highlighting how little scientists know about viral diversity in deep-sea ecosystems.
Researchers also discovered 16 “jumbo viruses” with unusually large genomes exceeding 200,000 base pairs. These included lineages related to the Chimalliviridae, a family of viruses known for forming nucleus-like structures inside bacterial cells that can help protect viral replication from host defenses.
A WARNING FOR DEEP-SEA MINING
The study also revealed that viruses play a significant role in regulating this harsh ecosystem by infecting bacteria living in the dark depths of the CCZ.
Through genes known as auxiliary metabolic genes (AMGs), viruses can alter the metabolism of their microbial hosts during infection, potentially influencing biogeochemical processes and nutrient cycling in the deep sea.
The findings come as the International Seabed Authority continues to develop regulations governing potential commercial deep-sea mining.
Scientists have raised concerns that mining operations could disturb seafloor habitats and generate sediment plumes, potentially affecting ecosystems that may take decades or longer to recover.
With thousands of newly identified viruses and much of their ecological role still unknown, the study’s authors stressed that understanding viral communities in the CCZ is essential to establishing environmental baselines and developing future impact assessments and conservation policies.
