The Surprising Undersea World at Pulley Ridge

This story is over at the U.S. Geological Survey website, with a last-modified date on it of April 12, 2005.

It seems that we don't know as much about where coral reefs can (and do) grow as we thought:

In the deep waters of the Gulf of Mexico, approximately 250 km west of Cape Sable, Florida, and 70 km west of the Dry Tortugas, are a series of drowned barrier islands known as Pulley Ridge. The ridge was found in 1950, but it wasn't until recent years that scientists discovered something extraordinary...

The Pulley Ridge coral reefs are much deeper than other known coral reefs, which means that they have much less light than usual to work with. They've adapted. Some of the colonies are flat instead of vertical, for instance. Use the title link for more info and a few photos.