This text was initially revealed by Hakai Journal.
Seaweed is flexible; it gives a habitat for marine life, shelters coastlines, and absorbs carbon dioxide. However in the US, scientists are getting down to see whether or not seaweed has one other notably invaluable trick hidden up its proverbial sleeve: to behave as a salty, slimy supply of valuable minerals.
Inside the U.S. Division of Power is the Superior Analysis Tasks Company-Power (ARPA-E), a scientific department dedicated to tackling difficult, high-potential initiatives on power applied sciences. ARPA-E takes huge swings and appears for large rewards. And to this point, the company has awarded $5 million to 3 ventures investigating whether or not seaweed can function a sensible supply of essential supplies, similar to platinum and rhodium, in addition to rare-earth parts, together with neodymium, lanthanum, yttrium, and dysprosium.
These invaluable parts, which could be captured and concentrated by seaweed, are important to the green-energy transition—and to expertise extra broadly. Seaweed may characterize a substitute for typical mining and different prospects, similar to deep-sea mining.
“There are a whole lot of complexities in your complete course of, and that’s why it’s within the class of ‘very exploratory,’” says Schery Umanzor, a seaweed professional on the College of Alaska at Fairbanks and a lead researcher on one of many initiatives funded by ARPA-E. “The possibilities of success are low. But when we succeed, then the implications are enormous.”
Two key rules underlie this analysis, Umanzor says. One, seaweed grows rapidly and sucks minerals out of the water to take action. Two, seaweed’s cell partitions are structured from sulfated polysaccharides—compounds made from lengthy chains of sugar molecules. Sulfated polysaccharides are negatively charged, which means they appeal to positively charged minerals floating close by. “It’s pure chemistry,” Umanzor says. “Optimistic with damaging, after which it simply collects.”
A number of years in the past, Scott Edmundson, on the U.S. Division of Power’s Pacific Northwest Nationwide Laboratory (PNNL) in Washington State, started digging into whether or not seaweed may retailer invaluable minerals. He’d come throughout a paper describing how rare-earth parts have been accumulating in seaweed in polluted areas alongside Morocco’s Atlantic coast and was struck by the potential.
Studying about seaweed’s pure propensity to sieve minerals from seawater sparked a “wacky thought” to check how far the method may go, Edmundson says. So he and different PNNL scientists ran an experiment to see if they may intentionally develop seaweed to take up minerals. The undertaking—which was additionally funded by ARPA-E—completed final 12 months, although they’re persevering with to dig into the subject. Thus far, the crew’s work suggests that seaweed could be processed to provide a carbon-rich element utilized in biofuel manufacturing and a second mineral element containing parts similar to phosphorus.
There are a lot of unknowns, Edmundson says. Completely different seaweeds seem to have distinct mechanisms for getting minerals out of seawater and distinctive methods of incorporating or concentrating them of their tissues. “There’s layers upon layers of variability which might be unclear for the time being,” he provides.
Underpinning all of this analysis are vital, unanswered questions, together with why seaweed absorbs these minerals in any respect, whether or not it will possibly accomplish that in concentrations excessive sufficient to be helpful, and whether or not the weather could be pulled out in a financially viable approach.
The important thing to creating all this work, Umanzor says, is determining find out how to extract metals and rare-earth parts from seaweed with out destroying it. For seaweed mining to make monetary sense, the method wants to go away the algae in good-enough situation to nonetheless be used for different functions, together with as gas, meals, or a element in bioplastic manufacturing.
One other essential piece of the puzzle is discovering the best spot to develop the seaweed. Regardless of their title, rare-earth parts aren’t all that uncommon. These and different essential minerals are current all through the ocean in tiny quantities. But there are areas the place they possible exist in greater concentrations—like downstream from giant deposits on land. That’s why Umanzor and her collaborators are inspecting whether or not rare-earth parts are sloughing off Bokan Mountain, in southeast Alaska, and ending up within the ocean, and whether or not rising seaweed in a close-by bay can snag what runs off. Bokan Mountain is being thought-about for typical mining, but when it really works, seaweed extraction may supply a extra sustainable various.
Susete Pintéus, a marine biologist on the Polytechnic Institute of Leiria in Portugal, co-authored a 2022 overview paper on seaweed’s function within the green-energy transition. She says seaweed extraction alone—if it really works—can not fully get rid of typical mining for these metals as a result of the demand is so nice. Seaweeds “can contribute,” she says, “however they won’t resolve the issue themselves.”
Regardless that seaweed assortment can’t totally change mining, Umanzor says that by extracting supplies as they leach naturally out of the land—as they may on Bokan Mountain—algal mining provides a approach to scoop up minerals that have been going to be misplaced to the ocean.
Umanzor by no means imagined that the standard seaweed may develop into a vessel to seize invaluable supplies. However on this function, it would assist a extra sustainable future.
“Metals have to come back from someplace, and extracting them may be very damaging,” she says. “It’s value exploring different potentialities that align extra with our concepts of a greener world—or a bluer world.”
