Pulley Ridge is a coral reef off the coast of southwestern Florida, United States  The reef lies 100 miles west of the Tortugas Ecological Reserve and stretches north about 60 miles. The ridge has a range of depth from 60–80 meters Pulley Ridge was originally discovered in 1950. It was found again in 1999 by scientist from the U.S. Geological Survey (USGS) and graduate students from the University of South Florida.
Pulley Ridge is the deepest coral reef off the shores of the continental United States. “Although deeper-water corals form reefs in the dark of ocean depths, Pulley Ridge is the deepest photosynthetic coral reef that we know of today,” said Robert Halley, USGS marine geologist.” Other reefs lie about 46 meters below sea level. During the exploration of Pulley Ridge, scientists found bioluminescent bacteria living in the reef. It is thought that this unique relationship between the bacteria and the coral is what keeps Pulley Ridge alive.
Coral reefs struggle to survive in the world today. “In the past 10 years the world has lost 25% of the known living coral reefs”. Coral reefs are particularly damaged by “…climate change, over fishing and coastal pollution”. Scientists hope that through the exploration of Pulley Ridge, they can gain new insight of how reefs function in order to better preserve other reefs.
The first scientific dive on Pulley Ridge
The first scientific dive on Pulley Ridge was led by James K. Culter of the Mote Marin Laboratory in Sarasota, Florida and included over 40 team members. The trip went from 23 June through 1 July 2005. The aim of this mission was to collect primary data and biological samples and to document marine life through still photographs and video The expedition was done at depths ranging from 200 to 260 feet. “…very few scientific reef investigations are conducted within the depth zone between traditional scuba air limits of 130 feet and deep-sea submersible research at and below 500 feet”.
After the expedition, Culter made some observations. He noticed some unusual neon colors in the reef. This bioluminescence may have some significance to the ridge. He also mentioned that compared to a shallow reef, there seemed to be fewer fish. Tilefish and groupers were seen at the ridge. He noted that this could have been because they were scared away by the divers or the fish could only come out at night. There appeared to be fewer crustaceans than one would normally see in a shallow reef, but there were several species of algae present. 
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- O'Hara, Timothy (2005-08-20). "Pulley Ridge coral reef fascinates scientists". CDNN-CYBER DIVER News Network. Retrieved 2007-02-20.]
- Photo album of Pulley Ridge
- GIS Compilation of Data Collected from the Pulley Ridge Deep Coral Reef Region United States Geological Survey