The Great Blue Hole

I am so captivated by this thing.

What Is It?

Reminding viewers of an enormous pupil, this fascinating piece of naturalness is known as The Great Blue Hole (hereafter GBH), and is a part of Belize’s Lighthouse Reef on the coast of the Caribbean Sea.

The Lighthouse Reef is an atoll. Atolls are distinct from other reef types, such as barrier and fringing. Most common in the Indian and Pacific oceans, atoll reefs enclose a space in the shape (ish) of a circle or horseshoe.

Atoll Reef Formation

The theory about how atoll reefs form goes like this (thank you, Darwin, among others):

At one point in time, living corals began to build a reef around a volcano or seamount (underwater mountain that does not break the surface). As the reef went through stages of fringing and barrier, the volcano or mountain cooled and eventually collapsed. The coral, needing light to live and grow, kept working its way toward the surface of the water. By the time we see it, the entire formation is simply a ring of coral around a lovely lagoon.

Why the Deep, Dark Blue?

Atoll reefs often display vibrant colors when seen from above – my favorite description thus far: peacock blue. This variety of light blues and greens is offset in the case of the GBH by the midnight blue of its lagoon. Estimated at 1,000 feet (300 meters) across and 400 feet (125 meters) deep, the hole is essentially an underwater cave.

I had a little trouble finding quick info on why this atoll has such a deep lagoon, but my guess is that it has to do with the age of the formation and the shape of the original mountain.

Basically, the GBH is a beautiful freak of nature, and older than we humans can fathom.  It’s like getting to see the passage of millions of years condensed into a hypnotic moment.

“I want to go to there…”

Do you want to visit what may be the world’s largest sea-hole? Of course you do. If you’ve got the money, time and gear, you may certainly swim in and explore this wild part of the planet. In addition to the GBH itself, the formation houses rare sea life and numerous caves.

Sources:

http://earthobservatory.nasa.gov/IOTD/view.php?id=37741

http://www.eoearth.org/article/Atoll

http://www.chaacreek.com/belize-travel-blog/2010/09/the-blue-hole-cousteau-never-had-it-so-good/

http://planetoddity.com/the-great-blue-hole-of-belize-worlds-deepest-sea-hole/