Pools of carbon dioxide, which scientists believe appear and disappear like a rain pool in the desert, have been found in the Aegean Sea off Greece's Santorini. They are interconnected and iridescent, and typically form at 820 feet deep, according to a release.

Located in the crater of the second-largest volcanic eruption in human history, the pools have never before been seen, and are very different from the typical brine pools found in oceans. Scientists believe they may lend us information on deep-sea carbon storage and a way to monitor the volcano for future eruptions, the release noted.

Researchers from Woods Hole Oceanographic Institution (WHOI), University of Girona, National Kapodistrian University of Athens, Institut de Physique du Globe de Paris, and Hellenic Center for Marine Research (HCMR), published their findings recently in the journal Scientific Reports. "Now these never-before-seen pools in the volcano's crater may help our civilization answer important questions about how carbon dioxide behaves in the ocean," lead author Rich Camilli, of WHOI, said in the release.

After a volcanic crisis in 2011, researchers began investigating a site of known hydrothermal activity inside the Santorini caldera. They located the pools using autonomous underwater vehicles (AUV) including Girona 500 from the University of Girona, a release said.

After that, HCMR launched a human-occupied vehicle that included robotic onboard chemical sensors . A smaller remotely operated vehicle (ROV) then sampled the pools' hydrothermal fluids, as the release stated.

Scientists have mainly seen brine pools of dissolved salt; these pools are distinctive for the fact that the carbon dioxide itself may be causing the water to be dense and to pool, according to the release.

While scientists have also previously believed carbon dioxide disperses throughout the ocean, in this case the carbon dioxide may collect in the deepest regions of the crater. This has implications for carbon capture and storage, they said in the release.

Follow Catherine on Twitter at @TreesWhales