The Florida Shelf Edge Exploration (FLOSEE) expedition, led by scientists at Florida Atlantic University's Harbor Branch Oceanographic Institute (HBOI), recently returned with video images and marine specimens from previously unmapped and unexplored deep coral ecosystems off Florida. South Florida is surrounded by shallow reefs, and HBOI scientists have learned that the deep-water reef ecosystems may be even more extensive. One major discovery was a deep-water Lophelia coral reef off the Florida Keys in 1,800 feet of water; this appears to be the southern-most living deep-water Lophelia reef in continental U.S. waters.
"Down slope from popular shallow dive sites are lush and diverse live bottom habitats that are home to commercial fish species and perhaps a safe haven for fish and coral species that are suffering in shallower environments due to human and natural stressors," said Shirley Pomponi, Ph.D., Executive Director of CIOERT. The NOAA Cooperative Institute for Ocean Exploration, Research and Technology (CIOERT) expedition, co-funded by NOAA's Office of Ocean Exploration and Research, and the NOAA Deep Sea Coral Research and Technology Program, set out to map and characterize the seafloor and fish communities inhabiting deep reefs beyond the reach of normal scuba operations. The expedition took place on the NOAA Ship Nancy Foster and used the University of Connecticut's Kraken II remotely operated vehicle (ROV), a tethered robot capable of diving and sampling down to 3,000 feet.
"It never ceases to amaze me that we continue to discover new formations and reefs in these areas that are relatively well-studied. It makes you want to know what is out there in the 95 percent of the ocean that we haven't even studied yet," said John Reed, Chief Scientist for HBOI.
The first week of the expedition focused on Pulley Ridge, the deepest tropical coral reef ecosystem known off the southeast U.S., inhabited by many of the same coral species in the Florida Keys but at depths of 230 to more than 300 feet. Pulley Ridge was recently designated as a marine protected area to help restore deep-water snapper and grouper species. The region is also the focus of a new, five-year NOAA program, sponsored by the NOAA Center for Sponsored Coastal Ocean Research and led by the University of Miami, in partnership with CIOERT, to understand the connectivity between deep and shallow reefs in the path of the Gulf Stream, from Mexico to Caribbean and southeast U.S. Atlantic reefs.
Using sonar maps and the ROV high-definition camera, FLOSEE scientists discovered extensive essential fish habitat for various grouper, including snowy, scamp, Warsaw and speckled hind. The expedition revisited photographic transects conducted by the U.S. Geological Survey in 2004. Based on preliminary observations, the cover of live coral on Pulley Ridge may have declined dramatically in the past two decades. Most of Pulley Ridge is now dominated by sponges and algae.
During leg two of the expedition, the focus was on deep-water protected areas off the Florida Keys, including the East Hump Marine Protected Area and Pourtales Terrace. The East Hump is part of a network of marine protected areas from North Carolina to Florida, established by the South Atlantic Fishery Management Council to sustain and restore reef fish populations and their habitat. Pourtales Terrace is also a managed area, or Coral Habitat Area of Particular Concern, designated by the Council to protect deep-sea coral ecosystems from destructive fishing practices, such as bottom trawling. In addition to the deep-water Lophelia coral reef, four deep-water sinkholes were discovered with piles of dugong rib bones, a manatee-like mammal which lived in Florida during the Miocene about 5 million years ago.
During the 19-day expedition, the ROV transited more than 30 miles during the 26 dives, collecting 100 hours of high definition videotapes, 5,700 digital images, and more than 150 samples of invertebrates, fish and algae. At night, plankton net tows sampled discrete layers of the water column and compared the samples with a new laser optics plankton recorder.
At the beginning of the expedition, HBOI engineers launched a Bluefin glider robot, a battery powered and buoyancy driven autonomous underwater vehicle that glides up and down in the water column, sampling the water column and sending its data via satellite back to the Institute. For the duration of the deployment, data were collected on water chemistry with a focus on ROV dive and plankton sampling sites.