Liquid Quarries and Reefs On Demand

[Image: Micromotors at work, via UCSD/ScienceDaily].

Tiny machines that can extract carbon dioxide from water might someday help deacidify the oceans, according to a press release put out last week by UCSD.

Described as "micromotors," the devices "are essentially six-micrometer-long tubes that help rapidly convert carbon dioxide into calcium carbonate, a solid mineral found in eggshells, the shells of various marine organisms, calcium supplements and cement."

While these are still just prototypes, and are far from ready actually to use anywhere in the wild, they appear to have proven remarkably effective in the lab:

In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

The implications of this for marine life are obviously pretty huge—after all, overly acidic waters mean that shells are difficult, if not impossible, to form, so these devices could have an enormously positive effect on sea life—but these devices could also be hugely useful in the creation of marine limestone.

As UCSD scientists explain, the micromotors would "rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form." A cloud of these machines could thus essentially precipitate the basic ingredients of future rocks from open water.

[Image: A Maltese limestone quarry, via Wikipedia].

At least two possibilities seem worth mentioning.

One is the creation of a kind of liquid quarry out of which solid rock could be extracted—a square mile or two of seawater where a slurry of calcium carbonate would snow down continuously, 24 hours a day, from the endless churning of invisible machines. Screen off a region of the coast somewhere, so that no fish can be harmed, then trawl those hazy waters for the raw materials of future rock, later to be cut, stacked, and sold for dry-land construction.

The other would be the possibility of, in effect, the large-scale depositional printing of new artificial reefs. Set loose these micromotors in what would appear to be a large, building-sized teabag that you slowly drag through the ocean waters, and new underwater landforms slowly accrete in its week. Given weeks, months, years, and you've effectively 3D-printed a series of new reefs, perfect for coastal protection, a new marine sanctuary, or even just a tourist site.

In any case, read more about the actual process over at UCSD or ScienceDaily.