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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In the Wake of the Deepwater Horizon Oil Spill, Gulf Dolphins Found Sick and Dying in Larger Numbers Than Ever Before

The Deepwater Horizon Oil Spill: Five Years Later

This is the third in a series of stories over the coming weeks looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

A dolphin is observed with oil on its skin on August 5, 2010, in Barataria Bay, La.

A dolphin is observed with oil on its skin on August 5, 2010, in Barataria Bay, Louisiana. (Louisiana Department of Wildlife and Fisheries/Mandy Tumlin)

Dolphins washing up dead in the northern Gulf of Mexico are not an uncommon phenomenon. What has been uncommon, however, is how many more dead bottlenose dolphins have been observed in coastal waters affected by the Deepwater Horizon oil spill in the five years since. In addition to these alarmingly high numbers, researchers have found that bottlenose dolphins living in those areas are in poor health, plagued by chronic lung disease and failed pregnancies.

Independent and government scientists have undertaken a number of studies to understand how this oil spill may have affected dolphins, observed swimming through oil and with oil on their skin, living in waters along the Gulf Coast. These ongoing efforts have included examining and analyzing dead dolphins stranded on beaches, using photography to monitor living populations, and performing comprehensive health examinations on live dolphins in areas both affected and unaffected by Deepwater Horizon oil.

The results of these rigorous studies, which recently have been and continue to be published in peer-reviewed scientific journals, show that, in the wake of the 2010 Deepwater Horizon oil spill and in the areas hardest hit, the dolphin populations of the northern Gulf of Mexico have been in crisis.

Troubled Waters

Due south of New Orleans, Louisiana, and northwest of the Macondo oil well that gushed millions of barrels of oil for 87 days, lies Barataria Bay. Its boundaries are a complex tangle of inlets and islands, part of the marshy delta where the Mississippi River meets the Gulf of Mexico and year-round home to a group of bottlenose dolphins.

During the Deepwater Horizon oil spill, this area was one of the most heavily oiled along the coast. Beginning the summer after the spill, record numbers of dolphins started stranding, or coming ashore, often dead, in Barataria Bay (Venn-Watson et al. 2015). One period of extremely high numbers of dolphin deaths in Barataria Bay, part of the ongoing, largest and longest-lasting dolphin die-off recorded in the Gulf of Mexico, persisted from August 2010 until December 2011.

In the summer of 2011, researchers also measured the health of dolphins living in Barataria Bay, comparing them with dolphins in Sarasota Bay, Florida, an area untouched by the Deepwater Horizon oil spill. Differences between the two populations were stark. Many Barataria Bay dolphins were in very poor health, some of them significantly underweight and five times more likely to have moderate-to-severe lung disease. Notably, the dolphins of Barataria Bay also were suffering from disturbingly low levels of key stress hormones which could prevent their bodies from responding appropriately to stressful situations. (Schwacke et al. 2014)

“The magnitude of the health effects that we saw was surprising,” said NOAA scientist Dr. Lori Schwacke, who helped lead this study. “We’ve done these health assessments in a number of locations across the southeast U.S. coast and we’ve never seen animals that were in this poor of condition.”

The types of illnesses observed in live Barataria Bay dolphins, which had sufficient opportunities to inhale or ingest oil following the 2010 spill, match those found in people and other animals also exposed to oil. In addition, the levels of other pollutants, such as DDT and PCBs, which previously have been linked to adverse health effects in marine mammals, were much lower in Barataria Bay dolphins than those from the west coast of Florida.

Dead in the Water

Based on findings from the 2011 study, the outlook for dolphins living in one of the most heavily oiled areas of the Gulf was grim. Nearly 20 percent of the Barataria Bay dolphins examined that year were not expected to live, and in fact, the carcass of one of them was found dead less than six months later (Schwacke et al. 2014). Scientists have continued to monitor the dolphins of Barataria Bay to document their health, survival, and success giving birth.

Considering these health conditions, it should come as little surprise that record high numbers of dolphins have been dying along the coasts of Louisiana (especially Barataria Bay), Alabama, and Mississippi. This ongoing, higher-than-usual marine mammal die-off, known as an unusual mortality event, has lasted over four years and claimed more than a thousand marine mammals, mostly bottlenose dolphins. For comparison, the next longest lasting Gulf die-off (in 2005–2006) ended after roughly a year and a half (Litz et al. 2014 [PDF]).

Researchers studying this exceptionally long unusual mortality event, which began in February 2010, identified within it multiple distinct groupings of dolphin deaths. All but one of them occurred after the Deepwater Horizon oil spill, which released oil from April to July 2010, and corresponded with areas exposed heavily to the oil, particularly Barataria Bay (Venn-Watson et al. 2015). In early 2011, the spring following the oil spill, Mississippi and Alabama saw a marked increase in dead dolphin calves, which either died late in pregnancy or soon after birth, and which would have been exposed to oil as they were developing.

The Gulf coasts of Florida and Texas, which received comparatively little oiling from the Deepwater Horizon spill, did not see the same significant annual increases in dead dolphins as the other Gulf states (Venn-Watson et al. 2015). For example, Louisiana sees an average of 20 dead whales and dolphins wash up each year, but in 2011 alone, this state recorded 163 (Litz et al. 2014 [PDF]).

The one grouping of dolphin deaths starting before the spill, from March to May 2010, took place in Louisiana’s Lake Pontchartrain (a brackish lagoon) and western Mississippi. Researchers observed both low salinity levels in this lake and tell-tale skin lesions thought to be associated with low salinity levels on this group of dolphins. This combined evidence supports that short-term, freshwater exposure in addition to cold weather early in 2010 may have been key contributors to those dolphin deaths prior to the Deepwater Horizon spill.

Legacy of a Spill?

A bottlenose dolphin swims in the shallow waters along a sandy beach with orange oil boom.

A bottlenose dolphin swims in the shallow waters along the beach in Grand Isle, Louisiana, near oil containment boom that was deployed on May 28, 2010. Oil from the Deepwater Horizon oil spill began washing up on beaches here one month after the drilling unit exploded. (U.S. Coast Guard)

In the past, large dolphin die-offs in the Gulf of Mexico could usually be tied to short-lived, discrete events, such as morbillivirus and marine biotoxins (resulting from harmful algal blooms). While studies are ongoing, the current evidence does not support that these past causes are responsible for the current increases in dolphin deaths in the northern Gulf since 2010 (Litz et al. 2014).

However, the Deepwater Horizon oil spill—its timing, location, and nature—offers the strongest evidence for explaining why so many dolphins have been sick and dying in the Gulf since 2010. Ongoing studies are assessing disease among dolphins that have died and potential changes in dolphin health over the years since the spill.

As is the case for deep-sea corals, the full effects of this oil spill on the long-lived and slow-to-mature bottlenose dolphins and other dolphins and whales in the Gulf may not appear for years. Find more information related to dolphin health in the Gulf of Mexico on NOAA’s Unusual Mortality Event and Gulf Spill Restoration websites.


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At the Bottom of the Gulf of Mexico, Corals and Diversity Suffered After Deepwater Horizon Oil Spill

The Deepwater Horizon Oil Spill: Five Years Later

This is the second in a series of stories over the coming weeks looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

Very little, if any, light from the sun successfully travels to the extreme bottom of the Gulf of Mexico. At these dark depths, the water is cold and the inescapable pressure of thousands of feet of ocean bears down on everything.

Yet life in the deep ocean is incredibly diverse. Here, delicate branches of soft coral are embraced by the curling arms of brittlestars. Slender sea fans, tinged with pink, reach for tiny morsels of food drifting down like snow from above. From minute marine worms to elongated fish, the diversity of the deep ocean is also a hallmark of its health and stability.

However, this picture of health was disrupted on April 20, 2010. Beginning that day and for almost three months after, the Macondo wellhead unleashed an unprecedented amount of oil and natural gas nearly a mile beneath the ocean. In addition, the response to this oil spill released large amounts of chemical dispersant, both at the source of the leaking oil and on the ocean surface. These actions were meant to break down oil that might have threatened life at the sea surface and on Gulf shores. Nevertheless, the implications for the ocean floor were largely unknown at the time.

In the five years since the Deepwater Horizon oil spill, a number of academic and independent scientists along with state and federal agencies, including NOAA and the Bureau of Ocean Energy Management, have been collaborating to study just how this oil spill and response affected the deep ocean and seafloor of the Gulf. What they found was the footprint of the oil spill on the seafloor, stamped on sickened deep-sea corals and out-of-balance communities of tiny marine invertebrates.

A Sickened Seafloor

A part of the world difficult to reach—and therefore difficult to know—the depths of the Gulf of Mexico required a huge collaborative and technological effort to study its inhabitants. Beginning in the fall of 2010, teams of scientists set out on multiple research cruises to collect deep-sea data, armed with specialized equipment, including remotely operated vehicles (ROVs), cameras capable of withstanding the crushing pressure of the deep ocean, and devices that could bore into the ocean bottom and scoop up multiple samples of sediments at a time.

Through these efforts, researchers have uncovered large areas of the Gulf of Mexico seafloor that contain most of the oil spill’s notable deep-sea impacts. One area in particular surrounds the damaged wellhead and stretches to the southwest, following the path of the massive underwater plume of Deepwater Horizon oil. At times, up to 650 feet thick and over a mile wide, the oil plume drifted at depths more than 3,500 feet beneath the ocean surface, leaving traces of its presence on the bottom as it went (Camilli et al. 2010).

The Macondo wellhead sits at the center of a bull’s-eye–shaped pattern of harm on the seafloor, with oil-related impacts lessening in intensity farther from the oil’s source. Further tying this pattern of injury to the Deepwater Horizon spill, a conservative chemical tracer of petroleum turned up in surface seafloor sediments extending 15 miles from the wellhead (Valentine et al. 2014).

Diversity Takes a Nose Dive

Few people ever see the bottom of the deep ocean. So what do these impacted areas actually look like? Starting several months after the leaking well was capped, researchers used ROVs and special cameras to dive down roughly 4,500 feet. They found multiple deep-sea coral colonies showing recent signs of poor health, stress, and tissue damage. On these corals, the polyps, which normally extend frilly tentacles from the corals’ branching arms, were pulled back, and excessive mucus hung from the corals’ skeletons, which also revealed patches of dead tissue. All of these symptoms have been observed in corals experimentally exposed to crude oil (White et al. 2012 PDF).

Five photos of deep-sea coral showing the progression of impacts over several years.

A time series of coral showing the progression of typical impacts at a site of coral colonies located less than seven miles from the source of Deepwater Horizon oil. You can see the brown “floc” material present in November 2010 disappears by March 2011 and afterward, is replaced by fuzzy gray hydroids and the coral loses its brittlestar companion. (Credit: Hsing et al. 2013)

Many of these coral colonies were partly or entirely coated in a clumpy brown material, which researchers referred to as “floc.” Chemical analysis of this material revealed the presence of petroleum droplets with similar chemical markers to Deepwater Horizon oil. The brittlestars usually associated with these corals also appeared in strange colors and positions. Some entire coral colonies were dead.

Research teams noted these observations only at corals within roughly 16 miles of the wellhead (White et al. 2012 PDF, Fisher et al. 2014). However, many similar coral colonies located further from the spill site showed no poor health effects.

Even one and two years later, deep-sea corals within the footprint of the spill still had not recovered. Hydroids took the place of the brown floc material on affected corals. Relatives of jellies, hydroids are fuzzy, grayish marine invertebrates that are known to encrust unhealthy coral.

Life on and under the sediment at the bottom of the Gulf also suffered, with the diversity of a wide range of marine life dropping across an area roughly three times the size of Manhattan (Montagna et al. 2013). Notably, numbers of tiny, pollution-tolerant nematodes increased in areas of moderate impact but at the expense of the number and types of other species, particularly copepods, small crustaceans at the base of the food chain. These effects were related to the concentration of oil compounds in sediments and to the distance from the Deepwater Horizon spill but not to natural oil seeps.

Top row, from left,  two types of crustaceans and a mollusk. Bottom row shows three types of marine worms known as polychaetes.

Examples of some of the common but very small marine invertebrates found living on and under the Gulf of Mexico seafloor. The top row shows, from left, two types of crustaceans and a mollusk, which are more sensitive to pollution. The bottom row shows three types of marine worms known as polychaetes, which tended to dominate ocean sediments with higher oil contamination found near corals. (Courtesy of Paul Montagna, Texas A&M University)

More sensitive to pollution, fewer types and numbers of crustaceans and mollusks were found in sediments around coral colonies showing impacts. Instead, a few types of segmented marine worms known as polychaetes tended to dominate ocean sediments with higher oil contamination near these corals (Fisher et al. 2014).

A Long Time Coming

Life on the bottom of the ocean moves slowly. Deep-sea corals live for hundreds to thousands of years, and their deaths are rare events. Some of the corals coated in oily brown floc are about 600 years old (Prouty et al. 2014). The observed impacts to life in the deep ocean are tied closely to the Deepwater Horizon oil spill, but the full extent of the harm and the eventual recovery may take years, even decades, to manifest (Fisher and Demopoulos, et al. 2014).

Learn more about the studies supported by the federal government’s Natural Resource Damage Assessment for the Deepwater Horizon oil spill, which determines the environmental harm due to the oil spill and response and seeks compensation from those responsible in order to restore the affected resources.

Read more: Deepwater Horizon Oil Spill Tied to Further Impacts in Shallower Water Corals, New Study Reports


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With Lobster Poacher Caught, NOAA Fishes out Illegal Traps from Florida Keys National Marine Sanctuary

This is a post by Katie Wagner of the Office of Response and Restoration’s Assessment and Restoration Division.

On June 26, 2014, metal sheets, cinder blocks, and pieces of lumber began rising to the ocean’s surface in the Florida Keys National Marine Sanctuary. This unusual activity marked the beginning of a project to remove materials used as illegal lobster fishing devices called “casitas” from sanctuary waters. Over the course of two months, the NOAA-led restoration team plans to visit 297 locations to recover and destroy an estimated 300 casitas.

NOAA’s Restoration Center is leading the project with the help of two contractors, Tetra Tech and Adventure Environmental, Inc. The removal effort is part of a criminal case against a commercial diver who for years used casitas to poach spiny lobsters from sanctuary waters. An organized industry, the illegal use of casitas to catch lobsters in the Florida Keys not only impacts the commercial lobster fishery but also injures seafloor habitat and marine life.

Casitas—Spanish for “little houses”—do not resemble traditional spiny lobster traps made of wooden slats and frames. “Casitas look like six-inch-high coffee tables and can be made of various materials,” explains NOAA marine habitat restoration specialist Sean Meehan, who is overseeing the removal effort.

The legs of the casitas can be made of treated lumber, parking blocks, or cinder blocks. Their roofs often are made of corrugated tin, plastic, quarter-inch steel, cement, dumpster walls, or other panel-like structures.

Poachers place casitas on the seafloor to attract spiny lobsters to a known location, where divers can return to quite the illegal catch.

A spiny lobster in a casita on the seafloor.

A spiny lobster in a casita. (NOAA)

“Casitas speak to the ecology and behavior of these lobsters,” says Meehan. “Lobsters feed at night and look for places to hide during the day. They are gregarious and like to assemble in groups under these structures.” When the lobsters are grouped under these casitas, divers can poach as many as 1,500 in one day, exceeding the daily catch limit of 250.

In addition to providing an unfair advantage to the few criminal divers using this method, the illegal use of casitas can harm the seafloor environment. A Natural Resource Damage Assessment, led by NOAA’s Restoration Center in 2008, concluded that the casitas injured seagrass and hard bottom areas, where marine life such as corals and sponges made their home. The structures can smother corals, sea fans, sponges, and seagrass, as well as the habitat that supports spiny lobster, fish, and other bottom-dwelling creatures.

Casitas are also considered marine debris and potentially can harm other habitats and organisms. When left on the ocean bottom, casitas can cause damage to a wider area when strong currents and storms move them across the seafloor, scraping across seagrass and smothering marine life.

“We know these casitas, as they are currently being built, move during storm events and also can be moved by divers to new areas,” says Meehan. However, simply removing the casitas will allow the seafloor to recover and support the many marine species in the sanctuary.

There are an estimated 1,500 casitas in Florida Keys National Marine Sanctuary waters, only a portion of which will be removed in the current effort. In this case, a judge ordered the convicted diver to sell two of his residences to cover the cost of removing hundreds of casitas from the sanctuary.

To identify the locations of the casitas, NOAA’s Hydrographic Systems and Technology Program partnered with the Restoration Center and the Florida Keys National Marine Sanctuary. In a coordinated effort, the NOAA team used Autonomous Underwater Vehicles (underwater robots) to conduct side scan sonar surveys, creating a picture of the sanctuary’s seafloor. The team also had help finding casitas from a GPS device confiscated from the convicted fisherman who placed them in the sanctuary.

After the casitas have been located, divers remove them by fastening each part of a casita’s structure to a rope and pulley mechanism or an inflatable lift bag used to float the materials to the surface. Surface crews then haul them out of the water and transport them to shore where they can be recycled or disposed.

For more information about the program behind this restoration effort, visit NOAA’s Damage Assessment, Remediation, and Restoration Program.

Katie Wagner.Katie Wagner is a communications specialist in the Assessment and Restoration Division of NOAA’s Office of Response and Restoration. Her work raises the visibility of NOAA’s effort to protect and restore coastal and marine resources following oil spills, releases of hazardous substances, and vessel groundings.


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Detecting Change in a Changing World: 25 Years After the Exxon Valdez Oil Spill

Life between high and low tide along the Alaskan coast is literally rough and tumble.

The marine animals and plants living there have to deal with both crashing sea waves at high tide and the drying heat of the sun at low tide. Such a life can be up and down, boom and bust, as favorable conditions come and go quickly and marine animals and plants are forced to react and repopulate just as quickly.

But what happens when oil from the tanker Exxon Valdez enters this dynamic picture—and 25 years later, still hasn’t completely left? What happens when bigger changes to the ocean and global climate begin arriving in these waters already in flux?

Telling the Difference

Two people wearing chest waders sift for marine life in shallow rocky waters.

In 2011 NOAA marine biologist Gary Shigenaka (right) sifts through the sediments of Alaska’s Lower Herring Bay, looking for the tiny marine life that live there. (Photo by Gerry Sanger/Sound Ecosystem Adventures)

In the 25 years since the Exxon Valdez oil spill hit Alaska’s Prince William Sound, NOAA scientists, including marine biologist Gary Shigenaka and ecologist Alan Mearns, have been studying the impacts of the spill and cleanup measures on these animals and plants in rocky tidal waters.

Their experiments and monitoring over the long term revealed a high degree of natural variability in these communities that was unrelated to the oil spill. They saw large changes in, for example, numbers of mussels, seaweeds, and barnacles from year to year even in areas known to be unaffected by the oil spill.

This translated into a major challenge. How do scientists tell the difference between shifts in marine communities due to natural variability and those changes caused by the oil spill?

Several key themes emerged from NOAA’s long-term monitoring and subsequent experimental research:

  • impact. How do we measure it?
  • recovery. How do we define it?
  • variability. How do we account for it?
  • subtle connection to large-scale oceanic influences. How do we recognize it?

What NOAA has learned from these themes informs our understanding of oil spill response and cleanup, as well as of ecosystems on a larger scale. None of this, however, would have been apparent without the long-term monitoring effort. This is an important lesson learned from the Exxon Valdez experience: that monitoring and research, often viewed as an unnecessary luxury in the context of a large oil spill response, are useful, even essential, for framing the scientific and practical lessons learned.

Remote Possibilities

As NOAA looks ahead to the future—and with the Gulf of Mexico’s Deepwater Horizon oil spill in our recent past—we can incorporate and apply lessons of the Exxon Valdez long-term program into how we will support response decisions and define impact and recovery.

The Arctic is a region of intense interest and scrutiny. Climate change is opening previously inaccessible waters and dramatically shifting what scientists previously considered “normal” environmental conditions. This is allowing new oil production and increased maritime traffic through Arctic waters, increasing the risk of oil spills in remote and changing environments.

If and when something bad happens in the Arctic, how do scientists determine the impact and what recovery means, if our reference point is a rapidly moving target? What is our model habitat for restoring one area impacted by oil when the “unimpacted” reference areas are undergoing their own major changes?

Illustrated infographic showing timeline of ecological recovery after the Exxon Valdez oil spill.

Tracking the progress of recovery for marine life and habitats following the Exxon Valdez oil spill is no easy task. Even today, not all of the species have recovered or we don’t have enough information to know. (NOAA) Click to enlarge.

Listening in

NOAA marine biologist Gary Shigenaka explores these questions as he reflects on the 25 years since the Exxon Valdez oil spill in the following Making Waves podcast from the National Ocean Service:

[NARRATOR] This all points back at what Gary says is the main take-away lesson after 25 years of studying the aftermath of this spill: the natural environment in Alaska and in the Arctic are rapidly changing. If we don’t understand that background change, then it’s really hard to say if an area has recovered or not after a big oil spill.

[GARY SHIGENAKA] “I think we need to really keep in mind that maybe our prior notions of recovery as returning to some pre-spill or absolute control condition may be outmoded. We need to really overlay that with the dynamic changes that are occurring for whatever reason and adjust our assessments and definitions accordingly. I don’t have the answers for the best way to do that. We’ve gotten some ideas from the work that we’ve done, but I think that as those changes begin to accelerate and become much more marked, then it’s going to be harder to do.”

 

Read a report by Gary Shigenaka summarizing information about the Exxon Valdez oil spill and response along with NOAA’s role and research on its recovery over the past 25 years.


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After the Big Spill, What Happened to the Ship Exxon Valdez?

This is a post by Gary Shigenaka, a marine biologist with NOAA’s Office of Response and Restoration.

Close-up of the ship's name on side of Exxon Valdez.

The last days of the Exxon Valdez: in the San Diego shipyard before the first name change. Photo from the collection of Gary Shigenaka, NOAA.

A popular myth exists that it is bad luck to rename a boat.  It is unclear whether this applies to “boats” as big as a 987-foot-long oil tanker, but it is possible that the ship originally known as the Exxon Valdez might be used to argue that the answer is “yes.”

When the Exxon Valdez was delivered to Exxon on December 11, 1986, it was the largest vessel ever built on the west coast of the U.S. On July 30, 1989, four months after it ran aground in Alaska’s Prince William Sound and caused the then-largest oil spill in U.S. waters, the crippled Exxon Valdez entered dry dock at National Steel and Shipbuilding in San Diego—its original birthplace.

The trip south from Prince William Sound had not been without incident. Divers discovered hull plates hanging from the frame 70 feet below the surface that had to be cut away, and a 10 mile oil slick trailing behind the ship for a time prevented it from entering San Diego Bay.

New Law, New Name

Ship Exxon Mediterranean in Trieste, Italy, July 1991.

Exxon Mediterranean in Trieste, Italy, July 1991. Photo by Arki Wagner, used with permission.

Nearly a year and $30 million later, the ship emerged for sea trials as the Exxon Mediterranean.  The Exxon Valdez had suffered the ignominy—and corporate hardship—of effectively being singled out in U.S. legislation (the Oil Pollution Act of 1990 [PDF]) and banned from a specific U.S. body of water:

SEC. 5007. LIMITATION.

Notwithstanding any other law, tank vessels that have spilled more than 1,000,000 gallons of oil into the marine environment after March 22, 1989, are prohibited from operating on the navigable waters of Prince William Sound, Alaska.

(33 U.S.C. § 2737)

With this banishment institutionalized in U.S. law, Exxon Shipping Company shifted the operational area for the ship to the Mediterranean and the Middle East and renamed it accordingly.  In 1993, Exxon spun off its shipping arm to a subsidiary, Sea River Maritime, Inc., and the Exxon Mediterranean became the Sea River Mediterranean.  This was shortened to S/R Mediterranean.

In 2002, the ship was re-assigned to Asian routes and then temporarily mothballed in an undisclosed location.

A Ship Singled Out?

Exxon filed suit in federal court challenging the provisions of the Oil Pollution Act of 1990 that had banned its tanker from the Prince William Sound trade route.  In November 2002, the Ninth Circuit Court of Appeals upheld the Oil Pollution Act and its vessel prohibition provision (the Justice Department noting that to that time, 18 vessels had been prevented from entering Prince William Sound).  While Sea River had argued that the law unfairly singled out and punished its tanker, and that there was no reason to believe that a tanker guilty of spilling in the past would spill in the future, the three-judge panel disagreed unanimously.

The Oil Pollution Act of 1990, the landmark law resulting from the Exxon Valdez oil spill, legislated the phase-out of all single-hulled tankers from U.S. waters by 2015. On October 21, 2003, single-hulled tankers carrying heavy oils were banned by the European Union.  A complete ban on single-hulled tankers was to be phased in on an accelerated schedule in 2005 and 2010. There remains pressure to eliminate single-hulled tankers from the oil trade worldwide, so their days are clearly numbered.

In 2005, the S/R Mediterranean was reflagged under the Marshall Islands after having remained a U.S.-flagged ship for 20 years (reportedly in the hopes that it eventually would have been permitted to re-enter the Alaska – U.S. West Coast – Panama route for which it had been designed).  The ship’s name became simply Mediterranean.

In 2008, ExxonMobil and its infamous tanker finally parted ways when Sea River sold the Mediterranean to a Hong Kong-based shipping company, Hong Kong Bloom Shipping Co., Ltd. The ship was once again renamed, to Dong Fang Ocean, and reflagged under Panamanian registry.  Its days as a tanker also came to an end, as the Dong Fang Ocean was converted into a bulk ore carrier at Guangzhou CSSC-Oceanline-GWS Marine Engineering Co., Ltd., China.

The Dong Fang Ocean labored in relative anonymity in its new incarnation until November 29, 2010.  On that day, it collided with another bulk carrier, the Aali in the Yellow Sea off Chengshan, China. Both vessels were severely damaged; the Dong Fang Ocean lost both anchors, and the Aali sustained damage to its ballast tanks.  The Dong Fang Ocean moved to the port of Longyan with assistance by tugs.

The End Is Near

With this last misfortune, the final countdown to oblivion began in earnest for the vessel-formerly-known-as-Exxon-Valdez.  In March 2011, the ship was sold for scrap to a U.S.-based company called Global Marketing Systems (GMS). GMS in turn re-sold it to the Chinese-owned Best Oasis, Ltd., for $16 million.

Exxon Valdez/Exxon Mediterranean/Sea River Mediterranean/S/R Mediterranean/Mediterranean/Dong Fang Ocean/Oriental Nicety being dismantled on the beach of Alang, India, 2012.

Exxon Valdez/Exxon Mediterranean/Sea River Mediterranean/S/R Mediterranean/Mediterranean/Dong Fang Ocean/Oriental Nicety being dismantled in Alang, India, 2012. Photo by ToxicsWatch Alliance.

Intending to bring the Oriental Nicety, as it had been renamed yet one last time, ashore at the infamous shipbreaking beaches of Alang, Gujarat, India, Best Oasis was blocked by a petition filed by Delhi-based ToxicsWatch Alliance with the Indian Supreme Court on the grounds that the ship could be contaminated with asbestos and PCBs. ToxicsWatch Alliance invoked the Basel Convention, which restricts the transboundary movements of hazardous wastes for disposal. However, an environmental audit required by the court showed no significant contamination, and in July 2012, the Oriental Nicety was cleared to be brought ashore for its final disposition. The ship was reportedly beached on August 2, 2012.

Shanta Barley, writing for Nature, penned a wry obituary as a lead-in to her article about the last days of the ship:

The Oriental Nicety (née Exxon Valdez), born in 1986 in San Diego, California, has died after a long struggle with bad publicity.

Editor’s note: Use Twitter to chat directly with NOAA marine biologist Gary Shigenaka about the Exxon Valdez and its impacts on Alaska’s marine life and waters on Monday, March 24 at 3:00 p.m. Eastern. Follow the conversation at #ExxonValdez25 and get the details: http://1.usa.gov/1iw2Y6W.

Gary Shigenaka.

Gary Shigenaka.

Gary Shigenaka is one of the original biological support specialists in the Emergency Response Division of NOAA’s Office of Response and Restoration. Even though his career with NOAA has spanned decades, Gary’s spill response experience began with the Exxon Valdez. He has worked countless spills since then, in the U.S. and internationally. He also currently oversees a number of response-related research efforts and represents the U.S. Department of Commerce on the Region 10 Regional Response Team.


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Where Are the Pacific Garbage Patches Located?

Microplastics in sand.

Microplastics, small plastics less than 5 millimeters long, are an increasingly common type of marine debris found in the water column (including the “garbage patches”) and on shorelines around the world. Based on research to date, most commonly used plastics do not fully degrade in the ocean and instead break down into smaller and smaller pieces. (NOAA Marine Debris Program)

The Pacific Ocean is massive. It’s the world’s largest and deepest ocean, and if you gathered up all of the Earth’s continents, these land masses would fit into the Pacific basin with a space the size of Africa to spare.

While the Pacific Ocean holds more than half of the planet’s free water, it also unfortunately holds a lot of the planet’s garbage (much of it plastic). But that trash isn’t spread evenly across the Pacific Ocean; a great deal of it ends up suspended in what are commonly referred to as “garbage patches.”

A combination of oceanic and atmospheric forces causes trash, free-floating sea life (for example, algae, plankton, and seaweed), and a variety of other things to collect in concentrations in certain parts of the ocean. In the Pacific Ocean, there are actually a few “Pacific garbage patches” of varying sizes as well as other locations where marine debris is known to accumulate.

The Eastern Pacific Garbage Patch (aka “Great Pacific Garbage Patch”)

In most cases when people talk about the “Great Pacific Garbage Patch,” they are referring to the Eastern Pacific garbage patch. This is located in a constantly moving and changing swirl of water roughly midway between Hawaii and California, in an atmospheric area known as the North Pacific Subtropical High.

NOAA National Weather Service meteorologist Ted Buehner describes the North Pacific High as involving “a broad area of sinking air resulting in higher atmospheric pressure, drier warmer temperatures and generally fair weather (as a result of the sinking air).”

This high pressure area remains in a semi-permanent state, affecting the movement of the ocean below. “Winds with high pressure tend to be light(er) and blow clockwise in the northern hemisphere out over the open ocean,” according to Buehner.

As a result, plastic and other debris floating at sea tend to get swept into the calm inner area of the North Pacific High, where the debris becomes trapped by oceanic and atmospheric forces and builds up at higher concentrations than surrounding waters. Over time, this has earned the area the nickname “garbage patch”—although the exact content, size, and location of the associated marine debris accumulations are still difficult to pin down.

Map of ocean currents, features, and areas of marine debris accumulation (including

This map is an oversimplification of ocean currents, features, and areas of marine debris accumulation (including “garbage patches”) in the Pacific Ocean. There are numerous factors that affect the location, size, and strength of all of these features throughout the year, including seasonality and El Nino/La Nina. (NOAA Marine Debris Program)

The Western Pacific Garbage Patch

On the opposite side of the Pacific Ocean, there is another so-called “garbage patch,” or area of marine debris buildup, off the southeast coast of Japan. This is the lesser known and studied, Western Pacific garbage patch. Southeast of the Kuroshio Extension (ocean current), researchers believe that this garbage patch is a small “recirculation gyre,” an area of clockwise-rotating water, much like an ocean eddy (Howell et al., 2012).

North Pacific Subtropical Convergence Zone

While not called a “garbage patch,” the North Pacific Subtropical Convergence Zone is another place in the Pacific Ocean where researchers have documented concentrations of marine debris. A combination of oceanic and atmospheric forces create this convergence zone, which is positioned north of the Hawaiian Islands but moves seasonally and dips even farther south toward Hawaii during El Niño years (Morishige et al., 2007, Pichel et al., 2007). The North Pacific Convergence Zone is an area where many open-water marine species live, feed, or migrate and where debris has been known to accumulate (Young et al. 2009). Hawaii’s islands and atolls end up catching a notable amount of marine debris as a result of this zone dipping southward closer to the archipelago (Donohue et al. 2001, Pichel et al., 2007).

But the Pacific Ocean isn’t the only ocean with marine debris troubles. Trash from humans is found in every ocean, from the Arctic (Bergmann and Klages, 2012) to the Antarctic (Eriksson et al., 2013), and similar oceanic processes form high-concentration areas where debris gathers in the Atlantic Ocean and elsewhere.

You can help keep trash from becoming marine debris by:

Carey Morishige, Pacific Islands regional coordinator for the NOAA Marine Debris Program, also contributed to this post.

Literature Cited

Bergmann, M. and M. Klages. 2012. Increase of litter at the Arctic deep-sea observatory HAUSGARTEN. Marine Pollution Bulletin, 64: 2734-2741.

Donohue, M.J., R.C. Boland, C.M. Sramek, and G.A Antonelis. 2001. Derelict fishing gear in the Northwestern Hawaiian Islands: diving surveys and debris removal in 1999 confirm threat to coral reef ecosystems. Marine Pollution Bulletin, 42 (12): 1301-1312.

Eriksson, C., H. Burton, S. Fitch, M. Schulz, and J. van den Hoff. 2013. Daily accumulation rates of marine debris on sub-Antarctic island beaches. Marine Pollution Bulletin, 66: 199-208.

Howell, E., S. Bograd, C. Morishige, M. Seki, and J. Polovina. 2012. On North Pacific circulation and associated marine debris concentration. Marine Pollution Bulletin, 65: 16-22.

Morishige, C., M. Donohue, E. Flint, C. Swenson, and C. Woolaway. 2007. Factors affecting marine debris deposition at French Frigate Shoals, Northwestern Hawaiian Islands Marine National Monument, 1990-2002. Marine Pollution Bulletin, 54: 1162-1169.

Pichel, W.G., J.H. Churnside, T.S. Veenstra, D.G. Foley, K.S. Friedman, R.E. Brainard, J.B. Nicoll, Q. Zheng and P. Clement-Colon. 2007. Marine debris collects within the North Pacific Subtropical Convergence Zone [PDF]. Marine Pollution Bulletin, 54: 1207-1211.

Young L. C., C. Vanderlip, D. C. Duffy, V. Afanasyev, and S. A. Shaffer. 2009. Bringing home the trash: do colony-based differences in foraging distribution lead to increased plastic ingestion in Laysan albatrosses? PLoS ONE 4 (10).


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Japan Confirms Dock on Washington Coast Is Tsunami Marine Debris

A worker uses a 30% bleach spray to decontaminate the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012.

January 3, 2013 — A worker uses a 30% bleach spray to decontaminate and reduce the spread of possible marine invasive species on the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012. (Washington Department of Fish and Wildlife/Allen Pleus)

The Japanese Consulate has confirmed that a 65-foot, concrete-and-foam dock that washed ashore in Washington’s Olympic National Park in late December 2012 is in fact one of three* docks from the fishing port of Misawa, Japan. These docks were swept out to sea during the earthquake and tsunami off of Japan in March 2011, and this is the second dock to be located. The first dock appeared on Agate Beach near Newport, Ore., in June 2012.

Using our trajectory forecast model, NOAA’s Office of Response and Restoration helped predict the approximate location of the dock after an initial sighting reported it to be floating somewhere off of Washington’s Olympic Peninsula. When the dock finally came aground, it ended up both inside the bounds of NOAA’s Olympic Coast National Marine Sanctuary and a designated wilderness portion of Olympic National Park.

Japanese tsunami dock located on beach within Olympic National Park and National Marine Sanctuary.

In order to minimize damage to the coastline and marine habitat, federal agencies are moving forward with plans to remove the dock. In addition to being located within a designated wilderness portion of Olympic National Park, the dock is also within NOAA’s Olympic Coast National Marine Sanctuary and adjacent to the Washington Islands National Wildlife Refuge Complex. (National Park Service)

According to the Washington State Department of Ecology, representatives from Olympic National Park, Washington State Department of Fish and Wildlife, and Washington Sea Grant Program have ventured out to the dock by land several times to examine, take samples, and clean the large structure.

Initial results from laboratory testing have identified 30-50 plant and animal species on the dock that are native to Japan but not the United States, including species of algae, seaweed, mussels, and barnacles.

In addition to scraping more than 400 pounds of organic material from the dock, the team washed its heavy side bumpers and the entire exterior structure with a diluted bleach solution to further decontaminate it, a method approved by the National Park Service and Olympic Coast National Marine Sanctuary.

Government representatives are examining possible options for removing the 185-ton dock from this remote and ecologically diverse coastal area.

Look for more information and updates on Japan tsunami marine debris at http://marinedebris.noaa.gov/tsunamidebris/.

*[UPDATE 4/5/2013: This story originally stated that four docks were missing from Misawa, Japan and that “the first dock was recovered shortly afterward on a nearby Japanese island.” We now know only three docks were swept from Misawa in the 2011 tsunami and none of them were found on a Japanese island. This dock has now been removed from the Washington coast.]