Dangerous bacteria can travel thousands of kilometers in oceans, Israeli study finds

The study, conducted by researchers at the University of Haifa and published in the journal Nature Communications, tracked huge clusters or “biomasses” of vibrio bacteria as they journeyed thousands of kilometres through maritime currents and water flows.

Large biomasses of potentially harmful bacteria can travel staggering distances across the ocean, putting animals and humans at heightened risk of infections, according to new research from Israeli scientists.

The study, conducted by researchers at the University of Haifa and published in the journal Nature Communications, tracked huge clusters or “biomasses” of vibrio bacteria as they journeyed thousands of kilometres through maritime currents and water flows.

Vibrio bacteria are found naturally in saltwater environments and most species are harmless to humans and marine life. However, certain strains like Vibrio cholerae can cause serious intestinal infections in people, while others pose threats to fish, coral, and other vital ocean ecosystems.

Using genomic sampling and ocean model simulations, the researchers discovered that substantial biomasses of vibrio bacteria can hitch rides on currents in a hibernation-like dormant state for months at a time, traversing entire ocean basins before becoming active again in new, far-flung locations.

“The notion that harmful micro-organisms can be ubiquitously distributed across the ocean by travelling thousands of kilometres in currents is a striking find,” said Dr Omri Gildor, who headed the study. “It suggests these bacteria could present a much broader risk of triggering infections than we previously imagined.”

The vibrio biomasses were found to originate in specific regions like the Red Sea and the Persian Gulf before dispersing across the Indian Ocean into the Pacific and Atlantic Oceans via major currents like the Agulhas and Gulf Stream.

In their dormant state within the currents, the bacteria were able to survive with limited nutrients and avoid being destroyed by ultraviolet radiation and other environmental stresses.

Once the biomasses reached more hospitable coastal areas with ample nutrients and warmer temperatures, the vibrio became active again and could potentially cause disease outbreaks, the researchers said. This finding may help explain some previous vibrio disease events where the bacteria appeared in unexpected locations far from their typical territories.

“This represents a potentially serious risk from a public health standpoint,” said study co-author Dr. Ariel Diamant. “With these bacteria able to revive in coastal waters, it increases the chances of human exposure through seafood, drinking water, or infected ocean waters.”

The authors called for increased monitoring of ocean currents as well as continued research into preventing and containing potential outbreaks of dangerous vibrio strains transported over long distances at sea.