Seaweed usually has the reputation of being a drab, slimy organism. But its reputation could receive a significant public relations bump with this latest discovery: a variety of brown algae that actually produces opals.

Cystoseira Tamariscifolia, also known as "rainbow wrack," is a lavish type of algae adorned with beautiful, bright blue and green iridescent orbs. Now for the first time, scientists at the University of Bristol have discovered that these sparkly ornaments are actually a new type of opal that the algae produces that can be turned off and on, according to a press release.

To be clear, the algae doesn't fashion gemstones. Rather, it gets its sheen by manipulating the nanostructure of oil droplets, a nanostructure found only one other place in nature: opals. It is an entirely new type of natural opal, but with the same shimmering opalescence.

Perhaps most impressive, however, is the fact that the seaweed seems capable of altering the nanostructure "at will," essentially tuning its opalescence to the always-changing sunlight in tidal rockpools. And it can make these changes in just a matter of hours.

"The formation of opals from oil droplets is a completely new discovery. If nanotechnologists were able to understand and mimic the dynamic properties of this seaweed opal, we may in the future have biodegradable, switchable display technology that may be used in packaging or very efficient, low cost solar cells," explained Dr. Martin Lopez-Garcia, one of the researchers who made the discovery.

The discovery was made thanks to technology that is capable of imaging the plant at a sub-nanoscale level. Researchers watched in wonder at how the assembly of structures found in the algae's chloroplast-containing cells changed from a lattice shape (when shimmering) to a more disorganized shape (when the shimmering gets turned off).

It's still a mystery as to why the seaweed makes these adjustments, but researchers suspect it's no coincidence that the process gets carried out in the same place where the plant's chloroplasts are found. It's possible that Cystoseira Tamariscifolia is utilizing the shimmer by scattering light to maximize exposure on the chloroplasts. More study will be needed to confirm this hypothesis, however.

"In the past decade, nanotechnologists have been able to make artificial opals out of similar glass nanospheres. But it seems that the humble seaweed is also able to make such artificial opals in its cells. So next time you're rock pooling in the U.K. during your summer holidays, see if you can find this amazing seaweed with its nano-manufacturing technology," added Dr. Ruth Oulton, another of the study's researchers.

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

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