Fighting coastal erosion with electricity

In the new study, researchers took inspiration from clams, mussels and other shell-dwelling sea life, which use dissolved minerals in seawater to build their shells.

Similarly, the researchers leveraged the same naturally occurring, dissolved minerals to form a natural cement between sea-soaked grains of sand. But, instead of using metabolic energy like mollusks do, the researchers used to spur the chemical reaction.

In laboratory experiments, a mild electrical current instantaneously changed the structure of marine sand, transforming it into a rock-like, immoveable solid. The researchers are hopeful this strategy could offer a lasting, inexpensive and sustainable solution for strengthening global coastlines.

The study, titled "Electrodeposition of calcareous cement from seawater in marine silica sands," appears in the journal Communications Earth & Environment.

"Over 40% of the world's population lives in ," said Northwestern's Alessandro Rotta Loria, who led the study. "Because of climate change and , erosion is an enormous threat to these communities. Through the disintegration of infrastructure and loss of land, erosion causes billions of dollars in damage per year worldwide. Current approaches to mitigate erosion involve building protection structures or injecting external binders into the subsurface.

An artistic impression of how electricity could be used to strengthen coastlines. Credit: Northwestern University

Samples of seawater-soaked sand in Rotta Loria's laboratory. The vertical, silver posts are electrodes. Credit: Northwestern University

Microscopy image of natural cement. Credit: Northwestern University

Sample of strengthened sand, treated with mild electricity, from the Rotta Loria lab. Credit: Northwestern University