3 months ago
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The erosion of coastlines threatens property and ecosystems, but scientists may have found a shocking solution in the form of electrical zaps. Using small charges, they were able to create a cement-like bond between grains of sand.
Alessandro Rotta Loria, an assistant professor at Northwestern University, noted in a statement that around 40% of the world’s population lives in coastal areas, and rising sea levels pose “an enormous threat to these communities.”
To find a solution, Loria and his team took inspiration from marine organisms like clams and mussels, which use their metabolic energy to convert seawater minerals into their skeletons and shells. Rotta Loria decided to a different energy source, in the form of electric shocks.
Because seawater contains a great number of dissolved minerals, as well a high number of ions, adding the charge can generate two common minerals: magnesium hydroxide and calcium carbonate. The latter is the primary material found in mollusk shells, while the former is common in many stones.
“My aim was to develop an approach capable of changing the status quo in coastal protection—one that didn’t require the construction of protection structures and could cement marine substrates without using actual cement,” said Rotta Loria.
In a study published in the journal Communications Earth and the Environment, Rotta Loria described experiments where electrical charges were applied to sand submerged in seawater. The team messed around with different voltages, the length of time voltages were applied to the sand, the density of the soil, and other variables. They found that while altering the power they used would alter the exact ratio of the minerals that were produced, they ultimately only needed a mild current of 2 or 3 volts to get what they were looking for: a material with the properties of a natural cement, holding sand particles together.
“After being treated, the sand looks like a rock,” Rotta Loria said. “It is still and solid, instead of granular and incohesive. The minerals themselves are much stronger than concrete, so the resulting sand could become as strong and solid as a sea wall.”
Because the required voltages are so low, Rotta Loria said they would pose no threat to coastal sea life.
“The applications of this approach are countless,” he said. “We can use it to strengthen the seabed beneath sea walls or stabilize sand dunes and retain unstable soil slopes. We could also use it to strengthen protection structures, marine foundations and so many other things. There are many ways to apply this to protect coastal areas.”
That’s potentially good news for anyone who enjoys chilling by the beach. According to the United States Climate Resilience Toolkit, coastal erosion causes around $500 million in property loss each year. In addition to the financial hit, erosion also leads to the annual loss of 80,000 acres of wetlands, which play a vital role in flood protection and maintaining water quality, not to mention their value for biodiversity and recreation. A 2020 study found that by the end of the century, as much as 26% of the planet’s beaches could disappear due to erosion.
