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.
Research from Florida Atlantic University had shown an expansion of Sargassum (a genus of brown macroalgae (‘seaweed’) in the waters and Gulf of Mexico coast beaches, as reported by Digital Journal (and with events occurring previously by our environment editor Karen Graham).
This expansion and the associated with potentially pathogenic Vibrio bacteria is facilitated by plastic pollution and climate change. On beaches it smells like rotten eggs and emits toxic gases. Little is known about the ecological relationship of Vibrio bacteria and Sargassum, although the presence of microplastics (upon which Vibrio adhere) get caught in the expanding algal.
The mass is making landfall in Florida and the Caribbean. In addition to the significant impacts to beaches, there is a connection to climate change. Sargassum grows quickly in warmer water; as the climate continues to warm, Sargassum and other algal blooms continue to grow.
The findings carry implications for both marine life and public health, to the extent they are described as the “perfect ‘pathogen’ storm” by the researchers.
In a more positive development, the Sargassum mass has decreased by 75 percent, leaving many coastal beaches unexpectedly clear. As the sargassum blob shrinks, the pathogen risk decreases. The reduction has been charted by the University of South Florida’s Optical Oceanography Lab.
Monitoring of the oceanographic phenomenon and proposals to decrease the levels have been led by the Environmental Defense Fund (EDF), a nonprofit organisation, has been working in the oceans in the U.S. and the world to find solutions to climate change that are good for people and the environment. The group see the Sargassum issue and its annual patterns as an opportunity to highlight the intersections between humans and the environment that are changing with a warming climate.
In addition, as the remaining Sargassum is optimised, there now exists the potential for the Sargassum that stays in the sea to sequester carbon and mitigate ocean acidification. This will ultimately help corals and other animals that need calcium bicarbonate. The seaweed is also a vital habitat for a wealth of other plants and animals and is rich in biodiversity, which contributes to healthy oceans.
The Great Sargassum Belt, as the 5,000-mile-long mass is known (as it stretches from the coast of West Africa to the Gulf of Mexico), is part of a larger story connected to many threats to the environment including pollution, shifting ocean conditions and climate change.
