NOAA's Response and Restoration Blog

An inside look at the science of cleaning up and fixing the mess of marine pollution

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NOAA and Partners Work Quickly to Save Corals Hit by Catamaran in Puerto Rico

Experts estimate that thousands of corals were broken, dislodged, buried, or destroyed when the 49-foot-long catamaran M/V Aubi ran aground along the north coast of Puerto Rico the night of May 14, 2015.

Traveling from the Dominican Republic to San Juan, Puerto Rico, the recreational boat became grounded on a coral reef, causing significant damage to the reef. As the vessel was being moved, the vessel’s two hulls slowly ground further into the reef, forming mounds of coral and leaving rubble on the ocean bottom. UPDATED 5/27/2015: The area of the vessel’s direct impact is 366 square meters (not quite 4,000 square feet), while partial impact covers more than 1,000 square meters (roughly 10,764 square feet).

On the night of the grounding, responders were immediately concerned about preventing a spill of the fuel on board the Aubi. The fuel had to be removed from the fuel tanks in the aluminum hulls of the catamaran before it was moved off of the coral reefs. By the evening of May 15, approximately 1,500 gallons of fuel had been removed successfully, readying the vessel to be towed from the reef. It was pulled free during high tide the next morning.

The location of the grounding is in a Puerto Rico Marine Reserve, overseen by the Puerto Rico Department of Natural and Environmental Resources.

Crushing News and Rubble Rousers

The species of coral affected by the accident are mostly Diploria, or brain coral, and Acropora palmata, or elkhorn coral. Listed as threatened under the Endangered Species Act, elkhorn coral is one of the most important reef-building corals in the Caribbean. Brain coral, found in the West Atlantic Ocean and the Caribbean, is also an important reef-building coral and is known for its stony, brain-like appearance.

Although there was significant damage to the coral, an oil spill fortunately was prevented. While exposure to oil may kill corals, it more frequently reduces their ability to perform photosynthesis and causes growth or reproductive problems.

A multi-organizational team, which included NOAA, was able to salvage over 800 coral colonies (or fragments of colonies), moving them into deeper water nearby for temporary holding.  About 75 very large colonies of brain coral were righted but unable to be moved because of their size.

Broken brain coral on seafloor.

Brain coral (Diploria) and elkhorn coral (Acropora palmata) represent the majority of the coral species affected by this vessel grounding. (NOAA)

With buckets and by hand, the team filled 50 loads of rubble (approximately nine cubic yards) into open kayaks and small boats to transport them to a deeper underwater site that Puerto Rico Department of Natural Resources had approved for dumping.  All that material, moved in one day, would otherwise likely have washed into the healthy reef adjacent to the damaged one and potentially caused even more harm.

While poor weather has been preventing further work at the grounding site this past week, the team expects to restart work soon. Once that happens, initial estimates are that it will take 10-15 days to reattach the salvaged corals and to secure the rubble most at risk of moving. Stabilizing or removing the remaining rubble and rebuilding the topographic complexity of the flattened seafloor, accomplished using large pieces of rubble, would likely take an additional 10 days.

Both the location and nature of the corals dominating the area make it a very viable location for complete restoration using nursery-grown corals, but the scope and scale would still need to be determined.

Small Boat, Big Impact?

Healthy brain coral on seafloor.

An area of healthy corals near the site of the grounded M/V Aubi. Divers acted quickly to protect these corals from being damaged by the large amounts of rubble loose on the seafloor after the accident. (NOAA)

Even though the vessel involved in this grounding was relatively small, an unofficial, anecdotal report from the team working on the site noted that the amount of damage appeared comparable to that caused by the groundings of much larger vessels, such as tankers.

If not for the quick work of the U.S. Coast Guard, Puerto Rico Department of Natural Resources, NOAA, support contractors, volunteers from non-governmental organizations, and members of the local community, the damage could have been much worse.

Healthy coral reefs are among the most biologically and economically valuable ecosystems on earth.

According to NOAA’s Coral Reef Conservation Program, a little-known fact is that corals are in fact animals, even though they may exhibit some of the characteristics of plants and are often mistaken for rocks.

Learn more about how NOAA dives to the rescue of corals in the Caribbean when they become damaged by grounded ships.


How NOAA Uses Coral Nurseries to Restore Damaged Reefs

Staghorn coral fragments hanging on an underwater tree structure of PVC pipes.

NOAA uses coral nurseries to help corals recover after traumatic events, such as a ship grounding. Hung on a tree structure, the staghorn coral shown here will have a better chance of surviving and being transplanted back onto a reef. (NOAA)

The cringe-inducing sound of a ship crushing its way onto a coral reef is often the beginning of the story. But, thanks to NOAA’s efforts, it is not usually the end. After most ship groundings on reefs, hundreds to thousands of small coral fragments may litter the ocean floor, where they would likely perish rolling around or buried under piles of rubble. However, by bringing these fragments into coral nurseries, we give them the opportunity to recover.

In the waters around Florida, Puerto Rico, and the U.S. Virgin Islands, NOAA works with a number of partners in various capacities to maintain 27 coral nurseries. These underwater safe havens serve a dual function. Not only do they provide a stable environment for injured corals to recuperate, but they also produce thousands of healthy young corals, ready to be transplanted into previously devastated areas.

Checking into the Nursery

When they enter coral nurseries, bits of coral typically measure about four inches long. They may come from the scene of a ship grounding or have been knocked loose from the seafloor after a powerful storm. Occasionally and with proper permission, they have been donated from healthy coral colonies to help stock nurseries. These donor corals typically heal within a few weeks. In fact, staghorn and elkhorn coral, threatened species which do well in nurseries, reproduce predominantly via small branches breaking off and reattaching somewhere new.

In the majority of nurseries, coral fragments are hung like clothes on a clothesline or ornaments on trees made of PVC pipes. Floating freely in the water, the corals receive better water circulation, avoid being attacked by predators such as fireworms or snails, and generally survive at a higher rate.

After we have established a coral nursery, divers may visit as little as a few times per year or as often as once per month if they need to keep algae from building up on the corals and infrastructure. “It helps if there is a good fish population in the area to clean the nurseries for you,” notes Sean Griffin, a coral reef restoration ecologist with NOAA.

Injured corals generally take at least a couple months to recover in the nurseries. After a year in the nursery, we can transplant the original staghorn or elkhorn colonies or cut multiple small fragments from them, which we then use either to expand the nursery or transplant them to degraded areas.

One of the fastest growing species, staghorn coral can grow up to eight inches in a year while elkhorn can grow four inches. We are still investigating the best ways to cultivate some of the slower growing species, such as boulder star coral and lobed star coral.

Growing up to Their Potential

In 2014, we placed hundreds of coral fragments from four new groundings into nurseries in Puerto Rico and the U.S. Virgin Islands. This represents only a fraction of this restoration technique’s potential.

After the tanker Margara ran aground on coral reefs in Puerto Rico in 2006, NOAA divers rescued 11,000 salvageable pieces of broken coral, which were reattached at the grounding site and established a nursery nearby using 100 fragments from the grounding. That nursery now has 2,000 corals in it. Each year, 1,600 of them are transplanted back onto the seafloor. The 400 remaining corals are broken into smaller fragments to restock the nursery. We continue to grow healthy corals in this nursery and then either transplant them back to the area affected by the grounded ship, help restore other degraded reefs, or use some of them to start the process over for another year.

Nurseries in Florida, Puerto Rico, and the U.S. Virgin Islands currently hold about 50,000 corals. Those same nurseries generate another 50,000 corals which we transplant onto restoration sites each year. Sometimes we are able to use these nurseries proactively to protect and preserve corals at risk. In the fall of 2014, a NOAA team worked with the University of Miami to rescue more than 200 threatened staghorn coral colonies being affected by excessive sediment in the waters off of Miami, Florida. The sedimentation was caused by a dredging project to expand the Port of Miami entrance channel.

We relocated these colonies to the coral nurseries off Key Biscayne run by our partners at the University of Miami. The corals were used to create over 1,000 four-inch-long fragments in the nursery. There, they will be allowed to recover until dredge operations finish at the Port of Miami and sedimentation issues are no longer a concern. The corals then can either be transplanted back onto the reef where they originated or used as brood stock in the nursery to propagate more corals for future restoration.

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When Ships Threaten Corals in the Caribbean, NOAA Dives to Their Rescue

Growing less than a quarter inch per year, the elaborate coral reefs off the south coast of Puerto Rico originally took thousands of years to form. And over the course of two days in late April 2006, portions of them were ground into dust.

The tanker Margara ran aground on these reefs near the entrance to Guayanilla Bay. Then, in the attempt to remove and refloat the ship, it made contact with the bottom several times and became grounded again. By the end, roughly two acres of coral were lost or injured. The seafloor was flattened and delicate corals crushed. Even today, a carpet of broken coral and rock remains in part of the area. This loose rubble becomes stirred up during storms, smothering young coral and preventing the reef’s full recovery.

NOAA and the Puerto Rico Department of Natural and Environmental Resources have been working on a restoration plan for this area, a draft of which they released for public comment in September 2014 [PDF]. In order to stabilize these rubble fields and return topographic complexity to the flattened seafloor, they proposed placing limestone and large boulders over the rubble and then transplanting corals to the area.

This is in addition to two years of emergency restoration actions, which included stabilizing some of the large rubble, reattaching around 10,500 corals, and monitoring the slow comeback and survival of young coral. In the future, even more restoration will be in the works to make up for the full suite of environmental impacts from this incident.

Caribbean Cruising for a Bruising

Unfortunately, the story of the Margara is not an unusual one. In 2014 alone, NOAA received reports of 37 vessel groundings in Puerto Rico and the U.S. Virgin Islands. About half of these cases threatened corals, prompting NOAA’s Restoration Center to send divers to investigate.

After a ship gets stuck on a coral reef, the first step for NOAA is assessing the situation underwater. If the vessel hasn’t been removed yet, NOAA often provides the salvage company with information such as known coral locations and water depths, which helps them determine how to remove the ship with minimal further damage to corals. Sometimes that means temporarily removing corals to protect them during salvage or figuring out areas to avoid hitting as the ship is extracted.

Once the ship is gone, NOAA divers estimate how many corals and which species were affected, as well as how deep the damage was to the structure of the reef itself. This gives them an idea of the scale of restoration needed. For example, if less than 100 corals were injured, restoration likely will take a few days. On the other hand, dealing with thousands of corals may take months.

NOAA already has done some form of restoration at two-thirds of the 18 vessel groundings with coral damage in the region this year. They have reattached 2,132 corals to date.

What does this look like? At first, it’s a lot of preparation. Divers collect the corals and fragments knocked loose by the ship; transport them to a safe, stable underwater location where they won’t be moved around; and dig out any corals buried in debris. When NOAA is ready to reattach corals, divers clear the transplant area (sometimes that means using a special undersea vacuum). On the ocean surface, people in a boat mix cement and send it down in five-gallon buckets to the divers below. Working with nails, rebar, and cement, the divers carefully reattach the corals to the seafloor, with the cement solidifying in a couple hours.

Protecting Coral, From the Law to the High Seas

Corals freshly cemented to the seafloor.

Corals freshly cemented to the seafloor. After a couple weeks, the cement becomes colonized by algae and other marine life so that it blends in with the reef. (NOAA)

Nearly a third of the total reported groundings in Puerto Rico and the U.S. Virgin Islands this year have involved corals listed as threatened under the Endangered Species Act. In previous years, only 10 percent of the groundings involved threatened corals. What changed this year was the Endangered Species Act listing of five additional coral species in the Caribbean.

Another form of protection for corals is installing buoys to mark the location of reefs in areas where ships keep grounding on them. Since these navigational aids were put in place at one vulnerable site in Culebra, Puerto Rico this summer, NOAA hasn’t been called in to an incident there yet.

But restoring coral reefs after a ship grounding almost wouldn’t be possible without coral nurseries. Here, NOAA is able to regrow and rehabilitate coral, a technique being used at the site of the T/V Margara grounding. Stay tuned because we’ll be going more in depth on coral nurseries, what they look like, and how they help us restore these amazingly diverse ocean habitats. [Update: Read how NOAA uses coral nurseries to restore damaged reefs.]

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With Tropical Storm Isaac’s Passing, Crews Resume Cutting Apart Grounded Ship and Protecting Coral at Mona Island, Puerto Rico

Response barges are anchored near the grounded M/V Jireh.

August 20, 2012 — Response barges are anchored near the M/V Jireh (foreground), which grounded on coral reefs in June. (U.S. Coast Guard/Jaclyn Young)

With the passage of the Tropical Storm formerly known as Hurricane Isaac, salvage crews and coral ecologists are once again back on Mona Island, Puerto Rico, working to remove the grounded freighter M/V Jireh while also protecting the island’s corals.

In previous ship salvage cases involving coral habitats, biologists have observed considerable coral damage from not only the physical placement of anchors, cables, and support vessels, but also continued shifting and grinding from the grounded vessel. As a result, crews are working carefully to keep that from happening here.

In such a long and complicated salvage project, it is impossible to prevent all impacts, but crews are continuing to remove and reattach corals at risk from the grounded ship. Nearly 1,000 corals have been moved already. These transplanted corals are expected to have a high survival rate and reduce the overall impacts from the vessel removal operation.

A NOAA-authorized biologist is on site during all coral relocation operations to make sure corals are properly handled and reattached to reefs. Before responders attempt to refloat the vessel, qualified divers will evaluate the corals in the area and determine an exit path for the damaged ship that will have the least impact to the surrounding coral habitat. This may or may not turn out to be the same path the ship took when it entered the reef. Depending on conditions after the vessel’s removal, the coral colonies may be relocated back to their original place on the reef.

The U.S. Coast Guard and the rest of the response crew have been working carefully to cut up portions of the ship, in order to lighten the vessel enough to refloat and remove it from the reef. Once disassembled, the removed portions of the ship are loaded onto a barge and taken to Puerto Rico for recycling.

Additionally, since the grounding on June 21, crews already have removed 600 tons of oiled cargo and more than 5,000 gallons of oil-water mixture.

Here you can see their plan for removing and disposing of this damaged vessel.

Jireh removal and disposal process.

Jireh removal and disposal process. (Jireh Grounding Unified Command)

Once the ship is refloated, the plan is to scuttle (purposefully sink) the wreck 12 miles away from Mona Island. After it is sunk, the wreckage is not expected to pose any additional risk to corals or other marine life. The difference with this shipwreck is the location.

“Intertidal wrecks are unstable and scour the reefs as they degrade and fall apart, while a wreck far out at sea becomes a stable deep-water habitat over time,” said Doug Helton, Incident Operations Coordinator for the Office of Response and Restoration.

The Coast Guard reports that removing the Jireh from Mona Island is the best solution to protect the sensitive environment and coral reefs surrounding this highly valuable natural reserve. Once this threat is permanently removed, NOAA divers will conduct an assessment of the grounding area and continue to work with local environmental agencies to ensure its full recovery.


Saving Coral After a Ship Grounds on a Reef in Puerto Rico

A ship run aground on coral reef in Puerto Rico is surrounded by protective oil boom.

The ship M/V Jireh, run aground on coral reef in Puerto Rico, is surrounded by protective oil boom. Credit: U.S. Fish and Wildlife Service.

Late last week a small freighter, the M/V Jireh, ran aground on Mona Island, an uninhabited island off Puerto Rico. The 22-square-mile island, an ecological reserve, is about 41 miles west of the main island of Puerto Rico. NOAA, U.S. Fish and Wildlife Service, Commonwealth of Puerto Rico, and U.S. Coast Guard are focusing on recovering the fuel and oil on board the freighter to minimize the environmental impact.

Efforts are underway to remove about 2,000 gallons of fuel oil from the Jireh. So far it looks like a major oil spill has been averted, but there is concern about the physical impact of the ship itself. As the ship plowed into the reef, it crushed and toppled corals. Unless restored, these unstable and barren areas may take generations to recover as tiny young coral larvae struggle to find a stable place to attach to the reef. Scientists are currently conducting a survey to see how much coral the ship affected.

[UPDATE JUNE 28, 2012: After surveying the underwater area around the grounded vessel, NOAA divers concluded that the ship caused minimal impact to coral. As of June 27, they were assessing whether any coral colonies or endangered species 300 feet out from the ship might be in its path as salvage teams attempted to refloat and remove it. NOAA would proactively remove and transplant any vulnerable species before salvage operations began.

Response crews have confirmed the Jireh is sound enough for them to go ahead and remove the diesel on board. They have deployed 100 feet of containment boom around the smaller response vessel ready to receive the fuel pumped off the Jireh. They also are removing a variety of oiled cargo from the ship, including mangoes, water bottles, cinder blocks, grain, bags of horse feed, and carbonated drinks.]

An injury doesn’t only stem from the grounded vessel. Anchors for the protective boom meant to contain any spilled oil have to be placed carefully to prevent additional damage, and care needs to be taken when the salvage tugs start to rig their own anchors and cables. About 800 feet of oil boom is currently strung around the vessel.

Some emergency actions can be taken to restore the coral reef, but recovery will still be slow. My office works to minimize those environmental impacts and develop restoration alternatives. If you are interested in other photos showing how we address coral injuries, take a look at the Maitland, Fla., and Cape Flattery, Hawaii, cases.

Mona Island is uninhabited, but there is a lot of shipping traffic nearby, and it has been affected by other ship groundings. In July 1997, the 325-foot container ship Fortuna Reefer ran aground on the south shore of the island, damaging approximately 6.8 acres of coral habitat. In September 1997, NOAA initiated an emergency restoration to the reef dominated by elkhorn coral (Acropora palmata) that was completed by mid-October 1997.


In Case of Offshore Oil Drilling in Cuba and the Bahamas

Map of potential oil producing areas in the North Cuban Basin.

Potential oil producing areas in the North Cuban Basin. (U.S. Geological Survey)

For the past year, we at NOAA and the U.S. Coast Guard have been studying the possible threats that new offshore oil drilling activity near the Florida Straits and the Bahamas pose to Florida.

For example, the proximity of Cuba’s oil fields to U.S. waters has raised a lot of concerns about what would happen if a spill like the 2010 Deepwater Horizon/BP oil well blowout happened. If a large oil spill did occur in the waters northwest of Cuba, currents in the Florida Straits could carry the oil to U.S. waters and coastal areas in Florida. However, a number of factors, like winds or currents, would determine where any oil slicks might go.

NOAA’s National Ocean Service has more information about how we’re preparing for worst-case scenarios there:

The study focuses on modeling the movement of oil in water to predict where, when, and how oil might reach U.S. shores given a spill in this region of the ocean.

Models help to determine the threat to our coasts from a potential spill by accounting for many different variables, such as the weathering processes of evaporation, dispersion, photo-oxidation, and biodegradation – all of which reduce the amount of oil in the water over time.

Currents and winds also play a role in determining where oil will move in water. For example, there are three major currents that would dominate movement of spilled oil near the Florida Straits: Loop Current, Florida Current, and the Gulf Stream.

A diver explores coral in the Florida Keys National Marine Sanctuary.

A diver explores coral in the Florida Keys National Marine Sanctuary. (NOAA)

If oil did reach U.S. waters, marine and coastal resources in southern Florida could be at risk, including coral reefs and the Florida Keys National Marine Sanctuary, located north of the Cuban drilling sites.

We’ll be watching the drilling activity there very carefully. If a spill does happen, NOAA will be ready to share our scientific expertise on oil spill response with the U.S. Coast Guard.