The Gulf of Mexico
Scattered colonies on carbonate blocks
Records of cold-water corals in the Gulf of Mexico (GoM) date back to surveys conducted by Pourtalès in the Straits of Florida and between the Dry Torugas and the Campeche Bank in the 19th century. In the deeper areas of the GoM, the substrata are mostly composed of fine sediments. However, unlike many cold-water coral habitats, much of the hard substrata colonised by corals are formed from authigenic carbonate (Go Deeper). These large carbonate blocks are deposited by biogeochemical activity that is associated with the seepage of hydrocarbons, a common feature of the GoM.
While there are substantial areas of cold-water coral habitat in the GoM, it appears to be more scattered and less extensive than such habitats off the southeastern US. Much of the research into the cold-water coral communities of the GoM has taken place along the northern continental slope. Here, several studies have found coral habitat consisting of reef building species such as Lophelia pertusa and Madrepora oculata. The most extensive cold-water coral communities found to date in the Gulf of Mexico occur at the Viosca Knoll, located on the upper DeSoto Slope, about 65 nautical miles south of the mouth of Mobile Bay, Alabama. The main Viosca Knoll site (called VK826) is an isolated feature that rises 90 m from the surrounding seafloor, providing high relief for an array of suspension feeders including scleractinian, gorgonian and anthipatharian corals.
Viosca Knoll was an important site for a 2008-2009 international collaboration between American, Dutch and Scottish researchers under the DISCOVRE project. In 2010 the Life on the Edge Expedition visited some of the GoM sites once again.
In 2010, the GoM went down in history as the site of the Deep-water Horizon tragedy where the largest deep-water oil spill in history gripped the world's attention. Evidence is emerging that some of the cold-water corals in the GoM may have been damaged by this deep-water oil spill, see report from Penn State University for more information.
Images, video and text have been donated by Dr. Steve W. Ross (Univ. NC-Wilmington), Dr. A. Demopoulos (US Geol. Survey), M. Rhode (Univ. NC-Wilmington) and M.S. Nizinski (NOAA Fisheries).