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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Solving the Case of the Mystery Sheen

Ocean with sheen. Image: U.S. Coast Guard.

Can you see the sheen in the distance? That lighter blue just below the horizon caught the attention of the U.S. Coast Guard helicopter crew that led to the discovery of a natural oil seep off the coast of San Diego, California. The sheen’s narrowing on the left with broader “feathering” on the right suggested a submerged source. Image credit: U.S. Coast Guard.

By Jordan Stout, NOAA Scientific Support Coordinator

In early March 2017, a U.S. Coast Guard helicopter was returning to its home base when the aircrew spotted a silvery sheen in the water about 35 miles west of San Diego, California.

I imagine the conversation among the crew went something like this:

Hey, that looks like it might be oil…

Is that from yesterday’s spill?  No sir, too far away…

Did any vessels sink out here recently?  Nothing’s been reported…

Do you see any debris in the water?  No sir, but I think I see bubbles coming to the surface within the sheen…

We’re pretty far offshore.  How deep is the water here?  Chart says about 300 fathoms (roughly 1,800 feet)…

Any other petroleum sources out here?  Not that I’m aware of.  Let’s call it in…

Reporting that finding of a mysterious sheen of oil on the ocean’s surface triggers a forensic process that typically requires the highly skilled staff of multiple federal agencies. In this instance, it included U.S. Coast Guard, several NOAA offices, and the U.S. Geological Survey.

Most Coast Guard aircrew members have overflown an oil spill at some point in their careers and many have seen our overflight job aid or taken the NOAA on-line training to help them identify and describe oil on the water.

In this case, the aircrew took photos and reported their observations to their command center. The crew’s initial report stated the sheen spanned approximately 400 yards by 10 yards, was patchy, thin, and unrecoverable.

Initial theories about the mystery sheen included:

  • A passing ship that spilled oil (by accident or intentionally)
  • A recent vessel casualty
  • An old shipwreck
  • An offshore disposal site, or
  • A natural oil seep

Theories in place, the next step was going through the list and systematically eliminating what could be causing the sheen.

Sheen shape, size, and area traffic

The Coast Guard is well known for conducting search and rescue operations when vessels are in distress and lives are at stake. It’s also responsible for ensuring safe and lawful maritime commerce. A check showed no large vessels had been in the area recently nor had any vessels (small or large) been reported missing.

The aircrew’s report of an oil “sheen” indicated to folks on shore that they had seen a very thin layer of oil (<50 microns) on the water’s surface.  That’s pretty darned thin, if you consider that a normal sheet of paper is about 100 microns thick.  Such thin layers don’t normally persist very long in the environment, so it wasn’t expected to stick around very long.

If the sheen had been spread out and patchy, it might be consistent with a spill from a passing ship or an earlier spill that had moved some distance over time.  Instead, the photos showed the sheen as a long linear feature, very narrow at one end and spread out and dissipating at the other (downstream) end.

During subsequent overflights for the next few days, the Coast Guard continued to see a similar sheen in the same location.  Because the original sheen would have dissipated in a matter of hours, these repeated sheen observations seemed to confirm an on-going, fixed source. But, what was it?

Both sunken vessels and natural seeps can release gases, so observing bubbles was interesting but not conclusive.  It could have been a sunken vessel, but in most cases, a sunken vessel will only release bubbles over a short period of time until the pockets of trapped air are all gone.  However, natural seeps can release gas bubbles continuously or sporadically for years.

Satellites, sunken ships and chemical analysis

Satellites – We checked with NOAA’s environmental satellite office, the National Environmental Satellite, Data, and Information Service, to see if any of their environmental satellite data/imagery had picked anything odd at that location recently or in any of their archived imagery.  They looked but they didn’t see anything obvious, but that’s not conclusive either.  Even the best satellite sensors for detecting oil on water have limitations.  There may very well have been a sheen out there, but it could not be distinguished with satellite data either because the winds were not optimal, the sheen was too small, or there was too much background “noise” in the data.

Maritime history – NOAA plays an important national role in identifying and protecting our nation’s maritime history.  As part of that stewardship role, NOAA and the Coast Guard partnered to evaluate which of the 1,000’s of shipwrecks in United States water might pose a substantial pollution threat.  This effort, called Remediation of Underwater Legacy Environmental Threats, or RULET, resulted in a series of reports in 2013.  No potentially polluting shipwrecks were identified off San Diego through the RULET program.

Charting – Another data source, the Resources and Under Sea Threats, called RUST, which includes shipwrecks and other potential pollution sources, only identified an ammunition dumpsite offshore of San Diego.  That site appears on the NOAA nautical charts, but is over 13 miles away.

Chemistry – A Coast Guard ship was sent out to obtain some sheen samples.  Chemical analysis from their Marine Safety Lab revealed the sheen contained petroleum oil with characteristics most resembling those of moderately weathered crude oil.  A vessel leaking fuel would not show a crude oil signature, but a natural seep would.

Two men on boat's deck taking water samples. Image USCG.

The helicopter crew guided a boat-based sampling team to the area. Samples were sent to the Coast Guard’s Marine Safety Lab for analysis. Image credit: U.S. Coast Guard.

And the Mystery Sheen is: a natural seep?

 The seas off Southern California are known to have hundreds of sub-sea natural oil seeps. Most of them are found off Santa Barbara, and quite a few off Los Angeles, according to Thomas Lorenson, research geologist with the U.S. Geological Survey at the Pacific Coastal and Marine Science Center.

“Recent seafloor mapping south of Santa Catalina Island shows subsea features like mounds that are often associated with oil or natural gas seepage, so it is not too surprising to discover another seep,” said Lorenson. “Luckily a person can pay a visit to a famous oil seep found on land at the La Brea Tar Pits in Los Angeles and imagine what they may look like underwater.”

So though we’ve not (yet) gotten visual confirmation of seep with a submersible or remotely operated vehicle, a natural seep on the sea floor remains the best explanation for this mystery.

 

Jordan Stout is the Scientific Support Coordinator in California, providing scientific input to the U.S. Coast Guard and Environmental Protection Agency for spills of oil and hazardous material.

 


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Keeping the Oil Pollution Act Updated

Cleanup worker and oiled boulders on Refugio State Beach where the oil from the pipeline entered the beach.

The pipeline release allowed an estimated 21,000 gallons of crude oil to reach the Pacific Ocean, shown here where the oil entered Refugio State Beach. (NOAA)

On August 18, 1990, President H.W. Bush signed the Oil Pollution Act.  The act gave NOAA and other agencies improved authorities for spill prevention, response, and restoration in the nation’s navigable waters and shorelines.

The act ensured those responsible for an oil spill must cleanup and restore the environment, and compensate the public for its lost uses—like beach and recreational fishery closures—from the time of the incident until those natural resources fully recover.

Now 27 years old, some parts of the law are dated. But, the Act signed by President Bush was not the final word on oil pollution.

Like many other laws, it has been subject to various amendments over time to address emerging issues or to strengthen or clarify the original law.

Often, the amendments advance through related legislation that move through Congress and reach the president. For example, a number of Oil Pollution Act amendments were added to U.S. Coast Guard authorization bills.

For instance, the Coast Guard Authorization Act of 2010 added a number of provisions including:

  • Requirements for oil transfers from vessels
  • Improvements to reduce human error and near miss incidents
  • Prevention of small oil spills
  • Improved coordination with tribal governments
  • Changed the definitions of certain ports
  • Altered uses of Oil Spill Liability Trust Fund by authorizing appropriations for NOAA and changed liability provisions for single hull vessels.

Sometimes these amendments can be quite technical but can also have significant impacts on how we work.  For example, the Coast Guard authorization act included this language that affected waterways near Seattle:

Within 1 year after the date of enactment of this Act, the Commandant shall initiate a rulemaking proceeding to modify the definition of the term ‘‘higher volume port area’’ in section 155.1020 of the Coast Guard regulations (33 C.F.R. 155.1020) by striking ‘‘Port Angeles, WA’’ in paragraph (13) of that section and inserting ‘‘Cape Flattery, WA’’.

There are about 15 higher volume port areas in the United States and these areas are subject to the most stringent response planning requirements.

As you might expect, these include the biggest oil ports in the nation, including New York, Houston, New Orleans, and Prince William Sound, Alaska.  In these high volume port areas, large amounts of response equipment has to be on standby, ready to deploy on very short notice.

However, Cape Flattery is on the northwest tip of Washington State. The fishing port of Neah Bay is nearby, but it is hardly a major oil port.

Hmm, so what did that accomplish? That simple definitional change meant that all tankers approaching the Strait of Juan de Fuca and oil terminals closer to Seattle had to have approved plans and meet the most stringent response times following a spill anywhere along our inland waters.  This required adding response vessels and equipment out near the entrance of the Strait and increasing the ability to rapidly respond to any spills.

There are already several bills in Congress this year that would further amend the Oil Pollution Act of 1990. In between spills and restoration work, we keep an eye on their progress through the legislative process.

You can read these articles for more information on the Oil Pollution Act of 1990:


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Polar Bears and Response Drills in Alaska

Two boats in fog with man on beach. Image: NOAA.

NOAA scientists scout for polar bears prior to disembarking for fieldwork at Beaufort Sea, Alaska. Image credit: NOAA.

How do you handle a polar bear covered in oil?  That was just one aspect of the annual Mutual Aid Deployment exercise last month on Alaska’s North Slope oil field.

Staff members from our Emergency Response Division and the Assessment and Restoration Division as well as other NOAA offices participated in the three-day exercise. Each year government agencies, oil companies, and oil spill removal organizations in the region work together to respond to a simulated oil spill in Alaska.

The scenario for this year’s drill was the simulation of an oil pipeline leak in the Beaufort Sea and the rescue of an oiled polar bear. In the exercise, the pipeline that was leaking belonged to Hilcorp, Alaska LLC. It was the first year the oil company hosted the event.

In addition to our office, participants included:

The exercise included field equipment deployment, an Incident Command Center, and remote operations in Anchorage.

Emergency Response Division staff participated in the Incident Management Team at the command center established at Hilcorp’s Endicott Facility on the Beaufort Sea north of Prudhoe Bay.

Staff from the Assessment and Restoration Division led the Natural Resource Damage Assessment component of the drill, that included a tabletop exercise with representatives from the state and federal agencies, and staff from Hilcorp. One Damage Assessment liaison was at the Endicott facility and the rest of the team participated remotely from Anchorage. The drill provided an opportunity to practice how a natural resource damage assessment would work with response early in a spill situation.

NOAA provides scientific support to the Coast Guard during oil and chemical spills, and the tools we’ve developed are an extension of that support. During the exercise, our GNOME trajectory-forecasting tool kept participants updated on where the spilled oil could go.

Arctic ERMA, our online Environmental Response Management Application, was continuously being updated with information on where the oil was as well as the location all the responders and their equipment. Environmental Sensitivity Index maps, which identify vulnerable wildlife and habitat potentially at risk from the spill, were displayed in ERMA.

Arctic ERMA display from response drill. Image: NOAA.

Information visualized on Arctic ERMA during the Mutual Aid Deployment exercise on Alaska’s North Slope oil field. Image credit: NOAA.

So how do you handle an oiled polar bear?

Very carefully and with a close eye on a timer.

Part of the drill was to see if an oil-injured polar bear could be tranquilized, pulled from the water, cleaned and caged before waking up.

Standing in for a real polar bear was an industrial-sized drum, filled with sand, covered with white cloth, and sporting a molded-foam head. The idea was to put the bear in the ocean and have emergency responders rescue the bear.

The rescue went well although some miscommunication early in the day added an unexpected element of realism—the team setting the fake bear in the lagoon did not anchor it, and due to heavy seas and winds on drill day, the bear drifted out into open water. However, the polar bear response team performed expertly and the fake bear was successfully located and rescued within the time allotted.

Fake polar bear on beach near dock. Image: NOAA.

The fake polar bear used for the Mutual Aid Deployment exercise on Alaska’s North Slope oil field. Image credit: NOAA.

You can read more about other simulated oil (and oranges and rubber ducks) spills in these articles:

 

Zachary Winters-Staszak, Catherine Berg, and Sarah Allan of the Office of Response and Restoration contributed to this article.

 


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Incident Responses for June 2017

Close up of skimming device on side of a boat with oil and boom.

Skimmers come in various designs but all basically work by removing the oil layer from the surface of the water. Image credit: U.S. Coast Guard

Every month our Emergency Response Division provides scientific expertise and services to the U.S. Coast Guard. Our services include everything from running oil spill trajectories to possible effects on wildlife and fisheries, and estimates on how long the oil may stay in the environment.

Several calls in June required our help to determine areas that might be effected by possible chemical releases. In those incidents, we used our CAMEO Chemicals modeling software to identify areas at risk.

Our Incident News website has information on oil spills and other incidents where we provided scientific support.

Here are some of this month’s responses:


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Incident Responses for May 2017

Gray whale rising from the ocean. Image credit: NOAA.

Gray whales are found mainly in shallow coastal waters in the North Pacific Ocean. Image credit: NOAA

Every month our Emergency Response Division provides scientific expertise and services to the U.S. Coast Guard on everything from running oil spill trajectories to model where the spill may spread, to possible effects on wildlife and fisheries, and estimates on how long the oil may stay in the environment.

In May, there were two incidents of dead gray whales in Washington state, one floating offshore near Long Beach, and another washed ashore in Bellingham Bay. In both cases, we were asked for trajectories.

In the case of a whale found floating at sea, we use our GNOME trajectory modeling software to map the possible drift route of the carcass. When a whale washes ashore, one of the things that officials need to know is how far they have to tow the carcass back out to sea to ensure it will not wash back to shore.

Our Incident News website has information on oil spills and other incidents where we provided scientific support.

Here are some of this month’s responses:

 


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Oil Spill Incident Responses for April 2017

Close up of skimming device on side of a boat with oil and boom. Image credit: U.S. coast Guard

The Emergency Response Division provides scientific expertise and services to the U.S. Coast Guard, including what equipment may be most efficient for containing spilled oil. Skimmers come in various designs but all basically work by removing the oil layer from the surface of the water. Image credit: U.S. Coast Guard

Oil spills come in all sizes from a pleasure boat’s small leak, to an oil platform explosion that results in environmental devastation, like the 2010 Deepwater Horizon incident.

Every month our Emergency Response Division provides scientific expertise and services to the U.S. Coast Guard on everything from running oil spill trajectories to where the spill may spread, to possible effects on wildlife and fisheries, and estimates on how long the oil may stay in the environment. Our Incident News website has information on oil spills and other incidents where we provided scientific support.

Here are this month’s responses:

Sunken Pleasure Craft, Pass a Loutre

Tug Powhatan

M/V Todd Brown

Mystery Sheen, NESDIS Report

BP Exploration Well #3, Prudhoe Bay, AK

U.S. Steel Hexavalent Chrome Release

F/V Bendora Aground

Vengeance crane barge sinking

Breton Sound Natural Gas Well Head 46D

UTV Michael Nadicksbernd

ATB Meredith Reinauer, Catskill, NY

MV Dawn

Anna Platform Pipeline Leak


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5 Ways the Coast Guard and NOAA Partner

Large ship on reef with small boat beside it.

On September 18, 2003, M/V Kent Reliant grounded at the entrance to San Juan Harbor, Puerto Rico. USCG and NOAA’s Office of Response and Restoration responded to the incident. (NOAA)

How do the Coast Guard and National Oceanic and Atmospheric Administration work together? There are many ways the two government organizations partner to keep the nation’s coasts and waterways safe for maritime commerce, recreational activities, and wildlife. Here are five:

1. It all began with surveyors and smugglers

Actually, it was an effort to suppress smuggling and collect tariffs that prompted President George Washington to create the Coast Guard Revenue Cutter Service in 1790, launching what would become the U.S. Coast Guard known today. It was President Jefferson’s approval of the surveying of the nation’s coasts in 1807 to promote “lives of our seamen, the interest of our merchants and the benefits to revenue,” that created the nation’s first science agency, which evolved into NOAA.

2. Coast Guard responds to spills; we supply the scientific support

The Coast Guard has the primary responsibility for managing oil and chemical spill clean-up activities. NOAA Office of Response and Restoration provides the science-based expertise and support needed to make informed decisions during emergency responses. Scientific Support Coordinators provide response information for each incident that spill’s characteristics, working closely with the Coast Guard’s federal On-Scene Coordinator. The scientific coordinator can offer models that forecast the movement and behavior of spilled oil, evaluation of the risk to resources, and suggest appropriate clean-up actions.

3. Coast Guard and NOAA Marine Debris Program keep waters clear for navigation

The Coast Guard sits on the Interagency Marine Debris Coordinating Committee, of which NOAA is the chair. The committee is a multi-agency body responsible for streamlining the federal government’s efforts to address marine debris. In some circumstances, the Coast Guard helps to locate reported marine debris or address larger items that are hazardous to navigation. For instance, in certain circumstances, the Coast Guard may destroy or sink a hazard to navigation at sea, as was the case with a Japanese vessel in the Gulf of Alaska in March 2011.

4. NOAA and Coast Guard train for oil spills in the Arctic

As Arctic ice contracts, shipping within and across the Arctic, oil and gas exploration, and tourism likely will increase, as will fishing, if fisheries continue migrating north to cooler waters. With more oil-powered activity in the Arctic and potentially out-of-date nautical charts, the region has an increased risk of oil spills. Although the Arctic may have “ice-free” summers, it will remain a difficult place to respond to spills, still facing conditions such as low visibility, mobilized icebergs, and extreme cold. The Office of Response and Restoration typically participates in oil spill response exercises with the Coast Guard.

5. It’s not just spills we partner on, sometimes it’s about birds

The Coast Guard as well as state and local agencies and organizations have been working to address potential pollution threats from a number of abandoned and derelict boats in the Florida. Vessels like these often still have oils and other hazardous materials on board, which can leak into the surrounding waters, posing a threat to public and environmental health and safety. In 2016, the Coast Guard called Scientific Support Coordinator Adam Davis with an unusual complication in their efforts: A pair of osprey had taken up residence on one of these abandoned vessels. The Coast Guard needed to know what kind of impacts might result from assessing the vessel’s pollution potential and what might be involved in potentially moving the osprey nest, or the vessel, if needed. Davis was able to assist in keeping the project moving forward and the vessel was eventually removed from the Florida Panhandle.