From Huffington Post

By: Becky Oskin

Charles Darwin sparked more than one controversy over the natural progression of life. One such case involved the evolution of coral atolls, the ring-shaped coral reefs that surround submerged tropical islands.

Coral reefs are actually huge colonies of tiny animals that need sunlight to grow. After seeing a reef encircling Moorea, near Tahiti, Darwin came up with his theory that coral atolls grow as reefs stretch toward sunlight while ocean islands slowly sink beneath the sea surface. (Cooling ocean crust, combined with the weight of massive islands, causes the islands to sink.)

A century-long controversy ensued after Darwin published his theory in 1842, because some scientists thought the atolls were simply a thin veneer of coral, not many thousands of feet thick as Darwin proposed. Deep drilling on reefs finally confirmed Darwin’s model in 1953.

But reef-building is more complex than Darwin thought, according to a new study published May 9 in the journal Geology. Although subsidence does play a role, a computer model found seesawing sea levels, which rise and fall with glacial cycles, are the primary driving force behind the striking patterns seen at islands today.

“Darwin actually got it mostly right, which is pretty amazing,” said Taylor Perron, the study’s co-author and a geologist at MIT. However, there’s one part Darwin missed. “He didn’t know about these glacially induced sea-level cycles,” Perron told OurAmazingPlanet.

What happens when sea-level shifts get thrown into the mix? Consider Hawaii as an example. Coral grows slowly there, because the ocean is colder than in the tropics. When sea level is at its lowest, the Big Island builds up a nice little reef terrace, like a fringe of hair on a balding pate. But the volcano — one of the tallest mountains in the world, if measured from the seafloor — is also quickly sinking. Add the speedy sea-level rise when glaciers melt, and Hawaii’s corals just can’t keep up. The reefs drown each time sea level rises.

The computer model accounts for the wide array of coral reefs seen at islands around the world — a variety Darwin’s model can’t explain, the researchers said.

“You can explain a lot of the variety you see just by combining these various processes — the sinking of islands, the growth of reefs, and the last few million years of sea level going up and down rather dramatically,” Perron told OurAmazingPlanet.

For nearly 4 million years, Earth has cycled through global chills, when big glaciers suck up water from the oceans, and swings to sweltering temperatures that melt the ice, quickly raising sea level. This cyclic growth of ice sheets takes about 100,000 years.

The researchers also found that one of the few places in the world where sinking islands and sea-level rise create perfect atolls is the Society Islands, where Darwin made his historic observations.

Do you know which species is the largest fish? Why whale sharks, of course.

You’ll find out many amazing facts like that in a fascinating feature on the Mesoamerican Reef that ran in National Geographic Magazine in October. The article features some awe inspiring images like this one, shot by photographer Brian Skerry, off the coast of the Yucatan, just north of Belize.

Big Fish, Little Fish: Trapped under ice, lost at sea, chased by sharks, photographer Brian Skerry has had more than a few scares in 35 years of catching images of underwater wildlife. Despite appearances to the contrary, this close encounter with a whale shark was quite the opposite. Snorkeling off Mexico’s Yucatán Peninsula, amid some 400 of the world’s biggest fish, Skerry spotted a massive maw coming at him with a remora darting around inside the giant filter feeder. “It’s not something the shark would eat,” notes Skerry of the suckerfish. Neither is he. Nonetheless, he quickly moved out of the way.

Photograph by Brian Skerry

Central America’s Mesoamerican Reef is half the length of its famous Australian counterpart but in many ways more remarkable. If you like coral reefs you’ll love this article.

The print edition of the article carried this wonderful map of the region (not available in the online version.) It highlights the coral reefs, mangrove forests and sea grass beds within the region. Check out where Adventure Island is!

belize-national-geographic

Glover’s Reef is famous for its pristine coral reef environment, which means snorkeling at our Long Caye island resort affords our guests easy access to some of the worlds most amazing marine life. The photo below is quite typical of what our guests might see while diving in our lagoon, especially if they’ve been quenching their thirst with a few of the local Belikin beers.

Anderson Cooper, in a report recently on 60 Minutes, visits with coral reef specialists at a remote coral reef off the coast of Cuba: The Gardens of the Queen. This reef is special in that, due to its remote location and the fact it has long been protected from over-fishing and other human/industrial depredations, it is one of the few reef systems in the world that is still thriving. In this regard, and because of it’s location in the Caribbean, it is remarkably similar to what is found at Glover’s Reef, also a world-class marine reserve.

The reef as described in the 60 Minutes episode could be about Glover’s Reef, where our island is located off the coast of Belize. View this episode to see what can be found at a healthy Caribbean coral reef.

Watch and enjoy the abundant, colorful marine life on Youtube: