A 5,000-mile-wide bunch of seaweed, roughly twice the width of the United States, is bearing down on the southwest coast of Florida, where residents may suffer respiratory problems as a result.
A huge swath of seaweed, also known as sargassum, wrought havoc with the water desalination plant on St. Croix in the Virgin Islands last summer. Governor Albert Bryan Jr. issued an executive order declaring a state of emergency because of the water shortage.
“Even if it’s just out in coastal waters, it can block intake valves for things like power plants or desalination plants, marinas can get completely inundated and boats can’t navigate through,” Brian Barnes, a professor at the University of South Florida’s College of Marine Science said of the looming problem, which currently is drifting between the Atlantic coast of Africa and the Gulf of Mexico. “It can really threaten critical infrastructure.”
“What we’re seeing in the satellite imagery does not bode well for a clean beach year,” Brian LaPointe, research professor at Florida Atlantic University’s Harbor Branch Oceanographic Institute, said, adding, “Following the big 2018 blooms, doctors in Martinique and Guadeloupe reported thousands of people going to clinics with breathing complications from the air that was coming off these rotting piles of sargassum.”
“Before 2011, it was there but we couldn’t observe it with satellites because it wasn’t dense enough,” Barnes commented. “Since then, it has just exploded and we now see these huge aggregations. … Historically, as far back as we have records, sargassum has been a part of the ecosystem, but the scale now is just so much bigger. What we would have thought was a major bloom five years ago is no longer even a blip.”
But there may be a silver lining for the seaweed cloud: the U.S. Department of Energy Bioenergy Technologies Office is examining the idea of combining wood waste with seaweed to make simple sugars microbes that could become biofuels. Acids or heat could be used to treat algae and wood waste and then turn the result into ethanol and possibly be used for sustainable aviation fuel that would produce 90% less greenhouse gas emissions than typical jet fuel. The leftover solids might be used for batteries in electric vehicles.
“We envision a sort of a dilute acid pretreatment as our baseline to make the sugars more accessible,” National Renewable Energy Laboratory (NREL) researcher Jacob Kruger said. “We might have to look at other chemical or mechanical treatments as well, and then plan to use enzymatic hydrolysis to render the sugars fermentable.”