Occasionally, however, eruptions can produce a few eye-catching wrinkles like the image below: A floating "island" made up of volcanic rock, meandering through the Pacific. There are millions of pieces of rock and each is a potential vehicle that offers a ride to small marine organisms such as algae, snails, barnacles and corals.
The pumice is now drifting westwards towards Fiji, and is likely to pass New Caledonia and Vanuatu before potentially reaching Australia in a year's time. "The whole ocean was matt - we couldn't see the water reflection of the moon". Because the pumice is porous, it tends to float, and now tons of the material - some of the rocks are as large as a basketball - is headed for the Great Barrier Reef.
Massive pumice raft on August 13.
Generally, Bryan said, corals "need to reach a reproductive age when they can start to spawn and release their larvae in the Great Barrier Reef". "[The raft] is a natural mechanism for species to colonize, restock and grow in a new environment", he added. The pumice floating toward Australia's Great Barrier Reef originates from a recently discovered underwater volcano, so recent that it still remains unnamed.
"It was a bit of a mystery, we didn't know how deep it was, if we were sailing over a volcano that was active at that moment", Larissa said.
"Reefs will be gone unless we tackle anthropogenic heating", Hughes wrote on Twitter, about atmospheric warming attributable to human actions comparable to burning fossil fuels. The water has been getting warmer and more acidic, causing unwanted events like coral bleaching that washes away the colors in corals, leaving them incapable of living.
The same day, NASA Earth Observatory revealed there's a mass of floating rock.
That, essentially, will help reestablish the Great Barrier Reef - which is the world's biggest coral reef and earth's greatest structure made by living organisms.
"First we thought it was whale poop", Whitehead told BBC.
Associate Prof Bryan said satellite images showed the field had since divided into two main surface masses, with many trailing "ribbons" of rock.