A key purpose of NOAA’s Office of Ocean Exploration and Research is to investigate the more than 95 percent of Earth’s underwater world that until now has remained virtually unknown and unseen. Such exploration may reveal clues to the origin of life on Earth, cures for human diseases, answers on how to achieve sustainable use of resources, links to our maritime history, and information to protect endangered species.
Most people are familiar with shallow water and deep-sea coral ecosystems, but ocean explorers are also focusing on a third type of coral ecosystem: light-dependent deep reefs living in what coral ecologists call the mesophotic zone (or “twilight zone”) in depths of 30 m to over 150 m, depending upon water clarity. Shallow-water coral reefs have been intensively studied by scientists using self-contained underwater breathing (SCUBA) equipment, while deep-sea coral systems are being investigated with human-occupied submersibles and remotely operated underwater vehicles (ROVs). Mesophotic coral ecosystems are beyond the safe range of conventional SCUBA equipment, yet are too shallow to justify the use of expensive submersibles and ROVs; but advances in undersea technologies over the past decade have begun to make investigating these ecosystems possible. While only a few studies of mesophotic reefs have been done using these new capabilities, data from these studies suggest these ecosystems include coral, sponge, and algal species that provide important refuges and nursery habitats for corals and fishes found on shallower reefs.
Pulley Ridge is a mesophotic coral ecosystem off the southwest coast of Florida in 60-80 meters depth, and is the deepest light-dependent coral reef that has been discovered off the United States. Pulley Ridge was originally discovered in 1950, and was found again in 1999 by scientists from the U.S. Geological Survey (USGS) and graduate students from the University of South Florida. Since then, a series of expeditions have revealed that coral ecosystems at Pulley Ridge are considerably healthier compared to the Florida Keys. Scientists hypothesize that Pulley Ridge may play an important role in replenishing key fish species, such as grouper and snapper, and other organisms in downstream reefs of the Florida Keys and Dry Tortugas. Since most of Florida’s reefs have severely declined over the past 30 years, this potential role means it is important to protect and manage Pulley Ridge as a possible source of larvae that can help sustain Florida’s reef ecosystems and the tourism economy that depends on them.
In 2011, NOAA’s National Centers for Coastal Ocean Science’s Center for Sponsored Coastal Ocean Research began a five-year project to investigate the role that the reefs of Pulley Ridge in the Gulf of Mexico may play in replenishing key fish species and other organisms in the downstream reefs. Explore the 2013 expedition at oceanexplorer.noaa.gov/explorations/13pulleyridge/welcome.html. The Coral Ecosystem Connectivity 2014 Expedition is the third year of this interdisciplinary study. Results will be used by resource managers to help manage and protect shallow and mesophotic coral ecosystems. During the 2014 expedition, fieldwork will include: Leg 1: June 18-27, 2014 (R/V Spree).
Leg 2: August 14-28, 2014 (R/V F.G. Walton Smith)
