The activities of humans have helped to create what researchers have described as the “perfect ‘pathogen’ storm,” a combination of Vibrio bacteria, seaweed and plastic marine debris.
The research comes from Florida Atlantic University, and it explores the ecological relationship of Vibrio bacteria with Sargassum (a genus of brown macroalgae (‘seaweed’) in the order Fucales) and particles from plastic waste. The findings carry implications for both marine life and public health.
The quantity of Sargassum and the populations of vibrio bacteria, together with the levels of microplastics, may seem like disparate subjects. They are not, but the interconnection needs to be made.
The Sargasso Sea is located entirely within the Atlantic Ocean. It is the only sea without a land boundary, and it is characterised by mats of free-floating sargassum, which provides shelter and habitat to many animals. Sargassum have been rapidly expanding in the Sargasso Sea. In addition, plastic marine debris is increasing in volume throughout the surface waters of the Sargasso Sea. The material persists for decades longer than natural substrates in the marine environment.
Species of Vibrio bacteria are found in waters around the world and the bacterium is a cause of death in human populations, including Vibrio vulnificus which can cause a life-threatening foodborne illness from seafood consumption. In addition, the bacterium can trigger disease from open wound infections.
Little is known about the ecological relationship of vibrio bacteria and Sargassum. It has also been unknown whether vibrio bacteria colonizing both plastic marine debris and Sargassum could potentially infect humans. Given there are a number of solutions to repurpose Sargassum. The researchers sought to assess whether these substrates pose a triple threat to public health.
The study began by sequencing the genomes of 16 Vibrio cultivars isolated from eel larvae, plastic marine debris, Sargassum, and seawater samples collected from the Caribbean and Sargasso seas of the North Atlantic Ocean.
An interesting early find was that Vibrio bacteria have an ability to “stick” to microplastics. In addition, there were signs that these microbes are adapting to living on plastic. Another evolutionary change, from an examination of the Vibrio metagenome-assembled genome, appears to be a blending of pathogenic and low nutrient acquisition genes, reflecting their pelagic habitat and the substrates and hosts the organisms seek to colonize.
Many of the organisms are also capable of rapid biofilm formation, plus haemolytic and lipophospholytic activities – both are tendencies consistent with pathogenic potential.
The study is published in the journal Water Research, titled “Sargasso Sea Vibrio bacteria: underexplored potential pathovars in a perturbed habitat.”
