Why Are Scientists Exploring Deep-Sea Coral and Sponge Communities in the Olympic Coast National Marine Sanctuary?
A key purpose of NOAA’s Ocean Exploration Initiative 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 to how to achieve sustainable use of resources, links to our maritime history, and information to protect endangered species.
For hundreds of years, fishermen have harvested coastal waters of the Pacific Northwest. Yet, the deepwater habitats that support these fisheries are poorly-studied and in many cases completely unknown. On deeper portions of the continental shelves, hard or ‘live’ bottom habitats support diverse biological communities that provide the foundation for the food web of many commercially- important species. Deep-water corals, particularly corals belonging to the genus Lophelia, form reefs that may have a diversity of species comparable to that of corals reefs in shallow waters. Often, sponges and soft corals are important parts of these reefs as well. But although shallow coral reefs have been studied extensively, scientists know very little about the ecology of coral communities in depths beyond the range of SCUBA gear.
The Olympic Coast National Marine Sanctuary (OCNMS) is an area of 3,310 square miles off of Washington State's Olympic Peninsula, as well as 135 miles of shoreline that includes some of the last remaining wilderness coastlines in the lower 48 states. The seaward boundary of the Sanctuary extents 40 miles offshore to depths of 1,400 m, and encompasses most of the continental shelf, as well as a variety of marine habitats including kelp beds, subtidal reefs, rocky and sandy intertidal zones, submarine canyons and plankton-rich upwelling zones. Acoustic surveys (see Exploration Technology, below) between 2001 and 2004 revealed deep, hard-bottom areas that scientists believe may include extensive coral and sponge communities. These habitats are part of one of the most productive marine ecosystems in North America, and support many commercial fisheries, including halibut, hake, salmon, and rockfish. The overall mission of the OCNMS is to protect the Olympic Coast's natural and cultural resources by conserving its resources as well as encouraging uses that are compatible with conservation.
A growing concern among managers of the OCNMS is the impact of bottom-fishing on deep-water coral and sponge habitats. Species that form deep-water habitats typically have long life-spans, slow growth rates, and fragile structures that make them particularly vulnerable and slow to recover from physical damage. Many investigations have reported large-scale damage to deepwater reefs caused by commercial fishing trawlers. There is also concern about damage that might result from other activities such as exploration and extraction of fossil fuels, and trenching for installation of submarine cables. Because the mission of the OCNMS is to protect the Olympic Coast's resources for the use and enjoyment of future generations, there is an urgent need to locate deep-sea coral and sponge communities so appropriate protective actions can be taken.
The central objective of the Olympic Coast Deep Corals Expedition was to document the location and condition of deep-sea coral and sponge communities in the Olympic Coast National Marine Sanctuary. Specific objectives included:
- Locating and mapping deep-sea coral and sponge communities in the Sanctuary;
- Characterizing diversity, abundance, and health of living marine resources associated with these communities; and
- Documenting the impact of fishing activities on these communities.
The technological foundation for the Olympic Coast Deep Corals Expedition included:
- Acoustic mapping to locate areas that are likely to contain deep-sea coral and sponge communities; and
- A Remotely Operated Vehicle (ROV) to provide video and photographic documentation of deep-sea coral and sponge communities, as well as to collect biological samples from these communities for species identification.
Acoustic mapping in the OCNMS involved various types of sonar (short for SOund NAvigation and Ranging) systems, which are used to determine water depth as well as to locate and identify underwater objects. In use, an acoustic signal or pulse of sound is transmitted into the water by a sort of underwater speaker known as a transducer. The transducer may be mounted on the hull of a ship, or may be towed in a container called a towfish. If the seafloor or other object is in the path of the sound pulse, the sound bounces off the object and returns an echo to the sonar transducer. The system measures the strength of the signal and the time elapsed between the emission of the sound pulse and the reception of the echo. This information is used to calculate the distance of the object, and an experienced operator can use the strength of the echo to make inferences about some of the object’s characteristics. Hard objects, for example, produce stronger echoes that softer objects. This is a general description of ‘active sonar’. ‘Passive sonar’ systems do not transmit sound pulses. Instead, they ‘listen’ to sounds emitted from marine animals, ships, and other sources. Subbottom profiler systems are another type of sonar system that emits low frequency sound waves that can penetrate up to 50 meters into the seafloor. Visit http://ocean.noaa.gov/technology/tools/sonar/sonar.html for more information about sonar systems.
Side-scan sonar systems use transducers housed in a towfish, usually dragged near the sea floor, to transmit sound pulses directed toward the side of the ship, rather than straight down. Return echoes are continuously recorded and analyzed by a processing computer. These data are used to construct images of the seafloor made up of dark and light areas. These images can be used to locate seafloor features (visit http://oceanexplorer.noaa.gov/technology/tools/sonar/sonar.html for more information).
Multibeam sonar systems are used to make bathymetric maps and create three-dimensional images of the seafloor. Multibeam sonars send out multiple, simultaneous sonar beams in a fan-shaped pattern that is perpendicular to the ship's track. This allows the seafloor on either side of the ship to be mapped at the same time as well as the area directly below (visit http://oceanexplorer.noaa.gov/technology/tools/sonar/sonar.html for more information).
ROV surveys during the Olympic Coast Deep Corals Expedition used the Remotely Operated Platform for Ocean Science (ROPOS), owned by the Canadian Scientific Submersible Facility. ROPOS is capable of operating to depths up to 5,000 meters, and is attached to the surface support vessel by a 5,500 m electrical-optical cable tether. The ROV typically carries two digital video cameras; two manipulator arms that can be fitted with different sampling tools (such as stainless steel jaws, manipulator feedback sensors, rope cutters, snap hooks, core tubes); a variable-speed suction sampler and rotating sampling tray; sonar; and a telemetry system. In addition, ROPOS can also be outfitted with up to eight custom-designed tools such as a hot-fluid sampler, chemical scanner, tubeworm stainer, rock-coring drill, rock-cutting chainsaw, laser-illuminated, range gated camera, and downward-looking digital scanning sonar. This wide variety of observation tools provides scientists with exceptional flexibility so they can quickly respond to new and unexpected discoveries. A typical ROPOS dive requires at least four people (and sometimes more): the "Hot Seat" scientist, pilot, manipulator operator, and data/event logger.
For more information about research submersibles, visit: http://oceanexplorer.noaa.gov/technology/subs/subs.html.
For more information about ROPOS, visit: http://oceanexplorer.noaa.gov/technology/subs/ropos/ropos.html.
More About Deep-Sea Corals
Recent studies suggest that deep-water coral ecosystems may have a diversity of species comparable to that of corals reefs in shallow waters, and have found deep-water coral species on continental margins worldwide. But while shallow-water coral reefs have been widely studied and well-publicized, reefs formed by deep-water corals are largely unexplored. One of the most conspicuous differences between shallow- and deep-water corals is that most shallow-water species have symbiotic algae (zooxanthellae) living inside the coral tissue, and these algae play an important part in reef-building and biological productivity. Deep-water corals do not contain symbiotic algae (so these corals are termed azooxanthellate). Yet, there are just as many species of deepwater corals (slightly more, in fact) as there are species of shallow-water corals.
Deep-water coral habitats occur at depths of 70 to greater than 1000 m. Typical deep-water coral species include Lophelia pertusa, Oculina varicosa, hydrocorals (family Stylasteridae), black corals (order Antipatharia), bamboo corals (family Isididae), and sea fans (order Gorgonacea). The deep-sea coral Lophelia pertusa is widely distributed in the world ocean, usually in depths of 400 to 700 m. Branches of living Lophelia coral grow on mounds of dead coral branches that can be several meters deep and hundreds of meters long. Lophelia does not have symbiotic algae and receives nutrition from plankton and particulate material captured by its polyps from the surrounding water. Lophelia mounds alter the flow of currents and provide habitats for many other organisms (Lophelia reef systems in the northeast Atlantic include more than 1,300 species of fish and invertebrates). Scientists suspect that many other organisms may also inhabit deep-sea coral reefs, including commercially-important fishes and crustaceans. But they don’t know for sure, because most deep-sea coral habitats are still unexplored.
In addition to their importance as habitats, deep-sea sponges and corals are sources of new pharmaceuticals that can be extremely valuable in treating human diseases. Examples include:
- Discodermolide: isolated from the sponge Discodermia dissolute ; may treat cancers which are resistant to other drugs;
- E7389: isolated from the sponge Lissodendoryx sp.; in clinical trials for the treatment of lung cancer and other cancers;
- Dictyostatin-1: isolated from a sponge from the order Lithistida; may be
- more effective than Taxol as an anti-cancer drug;
- Topsentin: isolated from the sponge Spongosporitesruetzleri, shows promise
- as an anti-inflammatory agent to treat arthritis and skin irritations, as well as for the treatment of Alzheimer’s disease and to prevent colon cancer;
- Bone Grafts: shallow tropical corals have been used as bone grafts for more than 10 years, but deep-sea species have not been used though recent research shows that bamboo corals (family Isididae) have a skeletal structure and dimensions that are almost identical to bone;
- Collagen: Gorgonin, found in bamboo corals, closely resembles collagen, an important component of bone that also can be used for controlled release of medicines, and as a foundation for tissue rebuilding.
Deep-sea corals usually inhabit places where natural disturbance is rare. Many of these corals are slow-growing and may require decades or even centuries to regenerate if they are damaged; but it really isn’t known whether these species are capable of recovering at all if they are damaged. Deep reefs worldwide are being impacted by human activities that include bottom-trawl fishing, oil and gas production, cable laying, mining, and coral harvest. Protecting the benefit offered by deep-sea coral reefs depends upon measures like the Deep Sea Coral Protection Act (DSCPA) which was introduced in the U.S. House and Senate in 2003-2004. Provisions of the Act include:
- Freezing the footprint of bottom trawls in all fishery management regions
- Preventing trawling from expanding into previously untrawled regions until deep-sea corals in those regions are surveyed and mapped
- Implementing a comprehensive research plan to collect information on deep-sea coral locations and life history
More About the Olympic Coast National Marine Sanctuary
The Olympic Coast National Marine Sanctuary represents one of North America's most productive marine ecosystems and spectacular undeveloped shorelines. Twenty nine species of marine mammals, scores of seabird species, numerous fishes, and many other organisms inhabit unique communities that include one of the most diverse seaweed communities in the world. The Sanctuary also has a rich cultural heritage that includes millennia of Native American habitation, the legacy of European exploration and settlement that dates from the 16th century, and nearly 180 documented shipwrecks in places with names like Destruction Island and Graveyard of the Giants. For more information on the OCNMS, visit: http://olympiccoast.noaa.gov.
More About the National Marine Sanctuary Program
The National Marine Sanctuary Program is administered by NOAA’s National Ocean Service (NOS) to manage and protect specially designated areas of the nation’s oceans and Great Lakes for their habitats, ecological value, threatened and endangered species, and historic, archeological, recreational and esthetic resources. The thirteen national marine sanctuaries include:
- Channel Islands (California)
- Cordell Bank (California)
- Fagatele (Fong’-uh-tell’-ee) Bay (American Samoa)
- Florida Keys (Florida)
- Flower Garden Banks (Texas/Louisiana)
- Gray’s Reef (Georgia)
- Gulf of the Farallones (California)
- Hawaiian Islands Humpback Whale (Hawaii)
- Monitor (North Carolina)
- Monterey Bay (California)
- Olympic Coast (Washington)
- Stellwagen Bank (Massachusetts)
- Thunder Bay (Michigan)
These sanctuaries range in size from one-quarter square mile to over 5,300 square miles. Together they include over 18,000 square miles of waters and marine habitats, an area nearly the size of Vermont and New Hampshire combined. Habitats represented within the sanctuaries include deep ocean and near-shore coral reefs, live bottom, whale migration corridors, deep sea canyons, areas of deep water upwelling, submerged banks that rise close to the ocean surface, kelp forests, and sea grass beds. Because they are formally designated as marine protected areas (MPAs), sanctuaries are focal points of conservation efforts. Coral reefs are closely monitored in five sanctuaries, and some also are the focus of special management activities and restoration efforts.
National marine sanctuaries are living classrooms and laboratories for students and marine scientists. Each sanctuary conducts its own education program and extensive research and monitoring efforts, often involving volunteers as well as Sanctuary Program staff. Over the years, thousands of people have volunteered their time to help preserve national marine sanctuaries.
Sanctuary advisory councils that include representatives from various user groups, government agencies and the public at large provide advice to sanctuary managers on the designation and operation of specific sanctuaries. In addition, ‘Friends’ groups assist the National Marine Sanctuary Program with education and outreach programs through fundraising activities for the Channel Islands, Florida Keys, Gulf of the Farallones, Monterey Bay and Olympic Coast National Marine Sanctuaries.
For more information, visit: http://oceanservice.noaa.gov/topics/oceans/nms/welcome.html.
For More Information
Contact Paula Keener-Chavis, national education coordinator for the NOAA Office of Ocean Exploration, for more information.
Other lesson plans developed for this Web site are available in the Education Section.