Lophelia Communities


Lophelia pertusa

Lophelia pertusa is a branching, tree-like, snow-white, deepwater coral.  Although widespread, Lophelia reefs form only under a particular set of favorable conditions: water temperatures must be continuously colder than about 50 degrees F; clean, hard rock substrate must initially be present for larval settlement; and strong bottom currents must be available to provide a steady supply of plankton for prey.  Mature Lophelia can grow to several meters in diameter and 1-3 meters high.  Based on radiocarbon dating, live Lophelia coral off the coast of Florida is estimated to be 700 years old.  Lophelia is fragile and easily broken by strong bottom currents or upon contact with large creatures.  The coral bush is also subject to attack from bio-eroders, including a boring sponge, which weaken the base of a colony over time. 

S.-Ross-Lophelia-047.jpgLophelia reefs are carpeted with a dense layer of living and dead coral rubble, a distinctive habitat in its own right.  Over thousands of years, a mosaic of coral banks and rubble fields have taken shape, providing a three-dimensional matrix that is home to many species of fishes and invertebrates.  Several types of crabs, anemones, brittle stars, sponges, and fishes make their home among or within the dead gray coral rubble.  On the bleak, current-swept plain of the Blake Plateau, Lophelia reefs are true biological oases in the deep sea.  Not only does the coral provide shelter for large, mobile animals, the hard substrate also allows attached invertebrates to gain a foothold.  The reef also provides an unusual zone of biological/physical interaction and ecological conjunction (Photo credit: S. Ross et al., UNCW).

Deep Water Coral Research and Management off the Southeastern United States  Steve W. Ross, Doug Rader, and Roger Pugliese 

Distribution

Lophelia is widespread throughout the world’s oceans, generally at depths between 400 and 3,000 meters but sometimes shallower in high latitudes.  However, Lophelia and associated communities remain poorly explored, namely due to their limited accessibility.  Lophelia reefs are known to exist in deep waters off Scandanavia, the British Isles, and the Blake Plateau in the Atlantic Ocean, as well as the Mediterranean Sea and the Gulf of Mexico.  Lophelia reefs tend to be found in areas where there are strong water currents, which supply food and remove sediments that would otherwise smother the coral polyps.  They are typically found along rocky ledges or in narrow regions.

Deepwater Coral HAPCs

In response to research revealing the importance and uniqueness of deepwater coral habitats in the South Atlantic, coupled with new reports prepared for the Council by J. Reed and S. Ross, the Council decided to propose HAPC designation for six deepwater coral areas to extend them a higher level of protection.  The Council’s Habitat and Coral Advisory Panels proposed these areas at the October 2004 meeting and the Council approved the proposal at their December 2004 meeting. Management measures proposed by the SAFMC to help protect these sensitive habitats received approval from NOAA Fisheries Service and the Secretary of Commerce and became effective July 22, 2010.  Five areas, located off the southeastern coast of the U.S. and encompassing more than 23,000 square miles (about the size of the State of West Virginia) have been designated Coral Habitat Areas of Particular Concern (Coral HAPCs).  The designation affords added protection to the areas that house an invaluable array of fish and invertebrate species, some of which may have biomedical applications in the treatment of human diseases.
 

Download a map of the coral HAPC areas (PDF). 

A brief description of each deepwater coral area is provided below summarized from General Description of Distribution, Habitat and Associated Fauna of Deep Water Coral Reefs on the North Carolina Continental Slope (Ross, 2004) and Deep-Water Coral Reefs of Florida, Georgia and South Carolina: A Summary of the Distribution, Habitat and Associated Fauna (Reed, 2004).

1. Cape Lookout Lophelia Banks
This HAPC encompasses two areas described by Dr. S. Ross in the above mentioned report.  This area was originally proposed for HAPC designation in 2004 and reviewed in June 2006. 

The northernmost area (Bank A) contains the most extensive coral mounds off North Carolina.  The main mound system rises vertically nearly 80 meters over a distance of about one kilometer.  Sides and tops of these mounds are covered with extensive Lophelia pertusa.  The second area (Bank B) contains mounds that rise at least 53 meters over a distance of about 0.4 kilometers. They appear to be of the same general construction as Bank A, built of coral rubble matrix that had trapped sediments.  Extensive fields of coral rubble surround the area.  Both living and dead corals are common to this bank, with some living bushes being quite large.  Over 43 fish species and over 11 fish species have been observed along Banks A and B, respectively.  In addition, these areas support a well-developed invertebrate fauna.

2. Cape Fear Lophelia Bank
This area was also originally proposed for HAPC designation in 2004 and its boundaries remain unchanged.

These mounds rise nearly 80 meters over a distance of about 0.4 kilometers and exhibit some of the most rugged habitat and vertical excursion of any area sampled.  They appear to be of the same general construction as Banks A and B (described above), built of coral rubble matrix that had trapped sediments.  Extensive fields of coral rubble surround the area.  Both living and dead corals are common on this bank.  Over 12 fish species have been observed, including the greatest numbers of large fishes off North Carolina.  In addition, this area supports a well-developed invertebrate fauna.  This is the only area off North Carolina where wreckfish have been observed.

3. Stetson Reef/Savannah and East Florida Lithoherms/Miami Terrace
This largest of the four proposed deepwater coral HAPCs encompasses three of the former proposed HAPCs off the coasts of South Carolina, Georgia and East Florida to the Miami Terrace off of Biscayne Bay and extends the western boundary to the 400-meter depth contour.  Below are descriptions of the main areas encompassed by this proposed HAPC.

Stetson Reef
This site is characterized by hundreds of pinnacles along the eastern Blake Plateau offshore South Carolina.  Over 200 coral mounds occur over this area.  This area supports a 152 meter-tall pinnacle in 822 meters of water where recent submersible dives discovered live bushes of Lophelia coral, sponges, gorgonians, and black coral bushes.  This represents one of the tallest Lophelia coral lithoherms known.  HBOI video 

Savannah and East Florida Lithoherms
This site is characterized by numerous lithoherms at depths of 550 meters with relief up to 60 meters that provide live-bottom habitat.  Submersible dives found that these lithoherns provided habitat for large populations of massive sponges and gorgonians in addition to smaller macroinvertebrates which have not been studied in detail.  Some ridges have nearly 100 percent cover of sponges.  Although few large fish have been observed at this site, a swordfish, several sharks, and numerous blackbelly rosefish were noted. Further south, echosounder transects along a 222-kilometer stretch off northeastern and central Florida (depth 700-800 meters) mapped nearly 300 coral mounds from 8 to 168 meters tall. HBOI video

Miami Terrace
The Miami Terrace and Escarpment is a Miocene-age terrace off southeast Florida that supports high relief hardbottom habitats and rich benthic communities in 200-600 meter depths.  Dense aggregations of 50 to 100 wreckfish were observed, in addition to blackbelly rosefish, skates, sharks, and dense schools of jacks.  Lophelia mounds are also present at the base of the escarpment, within the Straits of Florida, but little is known of their abundance, distribution, or associated fauna.  The steep escarpments, especially near the top of the ridges, are rich in corals, octocorals, and sponges.  HBOI video

4. Pourtales Terrace
The original proposed HAPC was expanded to include additonal, recently documented, deepwater coral habitat.

Like the Miami Terrace, the Pourtales Terrace is a Miocene-age terrace.  It is located off the Florida Reef Tract and provides high relief hardbottom habitats and rich benthic communities.  Sinkholes are present on the outer edge of the terrace, including the Jordon sinkhole, which may be one of the deepest sinkholes known.  A total of 26 fish taxa were identified from the sinkhole and bioherm sites.  Observed species include tilefish, sharks, speckled hind, yellow-edge grouper, Warsaw grouper, snowy grouper, blackbelly rosefish, red porgy, drum, scorpion fish, amberjack and phycid hakes.    HBOI video