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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What Are Our Options for Restoring Lands Around Washington’s Hanford Nuclear Reservation?

Shrub-covered plains next to the Columbia River and bluffs beyond.

The dry shrub-steppe habitat at Washington’s Hanford Nuclear Reservation is rare for the region because it is so extensive, intact, and relatively healthy. (Department of Energy)

Many people might be inclined to write off the wide, dry plains stretching around the Hanford Nuclear Reservation as lost lands. After all, this area in eastern Washington was central to the top-secret Manhattan Project, where plutonium was produced for nuclear bombs used against Japan near the end of World War II. In addition, nuclear production continued at Hanford throughout the Cold War, ending in 1987.

This history left an undeniable legacy of pollution, which is still being studied and addressed today.

Yet this land and the Columbia River that curves in and around it are far from being irredeemable. The Hanford site encompasses 586 square miles. Yes, some parts of Hanford have been degraded by development from its nine (now decommissioned) nuclear reactors and associated processing plants and from chemical and radionuclide contamination.

But the site also includes vast, continuous tracts of healthy arid lands that are rare in a modern reality where little of nature remains untouched by humans.

Where We Are and Where We’re Going

This potential is precisely what encourages Christina Galitsky, who recently joined NOAA’s Office of Response and Restoration to work on the Hanford case. Currently, she is leading a study at Hanford as part of a collaborative effort known as a Natural Resource Damage Assessment, a process which is seeking to assess and make up for the years of environmental impacts at the nuclear site.

“The purpose of our study is to begin to understand habitat restoration options for Hanford,” Galitsky explained. “We are starting with terrestrial habitats and will later move to the aquatic environment.”

A worker drains a pipe that contains liquid chromium next to a nuclear reactor.

From the 1940s to 1980s, the Hanford site was used to produce plutonium in nuclear weapons, and which today is home to the largest environmental cleanup in the United States. Here, a cleanup worker deals with chromium pollution near one of the decommissioned nuclear reactors. (Department of Energy)

NOAA is involved with eight other federal, state, and tribal organizations that make up the Hanford Natural Resource Trustee Council, which was chartered to address natural resources impacted by past and ongoing releases of hazardous substances on the Hanford Nuclear Reservation.

The study, begun in the summer of 2015, will be crucial for helping to inform not only restoration approaches but also the magnitude of the environmental injury assessment.

“We want to understand what habitat conditions we have at Hanford now,” Galitsky said, “what restoration has been done in similar dry-climate, shrub-steppe habitats elsewhere and at Hanford; what restoration techniques would be most successful and least costly over the long term; and how to best monitor and adapt our approaches over time to ensure maximum ecological benefit far into the future.”

The Hanford site is dominated by shrub-steppe habitat. Shrub-steppe is characterized by shrubs, such as big sagebrush, grasses, and other plants that manage to survive with extremely little rainfall. The larger Hanford site, comprised of the Hanford Reach National Monument and the central area where nuclear production occurred, contains the largest blocks of relatively intact shrub-steppe habitat that remain in the Columbia River Basin.

More Work Ahead

Roads and facilities of Hanford next to the Columbia River with bluffs and hills beyond.

The Hanford site, which the Columbia River passes through, encompasses 586 square miles of sweeping plains alongside an atomic legacy. (Department of Energy)

Galitsky’s team includes experts from NOAA, the Washington Department of Fish and Wildlife, and other trustees involved in the damage assessment. For this study, they are reviewing reports, visiting reference and restoration sites in the field, creating maps, and organizing the information into a database to access and analyze it more effectively.

They presented their preliminary results to the trustee council in November. So far, they are finding that limited restoration has been done at Hanford, and, as is fairly common, long-term data tracking the success of those efforts are even more limited. Over the next six months, they will expand their research to restoration of similar shrub-steppe habitats elsewhere in the Columbia Basin and beyond.

Thanks to additional funding that stretches into 2017, the team will begin a second phase of the study later this year. Plans for this phase include recommending restoration and long-term habitat management approaches for the trustee council’s restoration plan and examining the benefits and drawbacks of conducting shrub-steppe restoration both on and off the Hanford site.

Steppe up to the Challenge

Two American White Pelicans fly over the Columbia River and Hanford's shrubby grasslands.

A surprising diversity of plants and animals, such as these American White Pelicans, can be found in the lands and waters of Hanford. (NOAA)

The natural areas around Hanford show exceptional diversity in a relatively small area. More than 250 bird species, 700 plant species, 2,000 insect species, and myriad reptiles, amphibians, and mammals inhabit the site. In addition, its lands are or have been home to many rare, threatened, and sensitive plants, birds, reptiles, and mammals, such as the Pygmy rabbit

Furthermore, the shrub-steppe habitat at Hanford holds special significance because this habitat is so rare in the Columbia Basin. Elsewhere in the region, urban and agricultural development, invasive species, and altered fire regimes continue to threaten what remains of it. As Galitsky points out, “At Hanford there is an opportunity to restore areas of degraded shrub-steppe habitat and protect these unique resources for generations.”

Restoring habitats on or near the Hanford site may create benefits not only on a local level but also more broadly on a landscape scale. These efforts have the potential to increase the connectivity of the landscape, creating corridors for wildlife and plants across the larger Columbia River Basin. The team will be evaluating these potential landscape-scale effects in the second phase of this project. Stay tuned.


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How Do You Keep Killer Whales Away From an Oil Spill?

This is a guest post by Lynne Barre of NOAA Fisheries.

Two killer whales (orcas) breach in front a boat.

NOAA developed an oil spill response plan for killer whales that includes three main techniques to deploy quickly to keep these endangered animals away from a spill. (NOAA)

I sleep better at night knowing that we have a plan in place to keep endangered Southern Resident killer whales away from an oil spill. Preventing oil spills is key, but since killer whales, also known as orcas, spend much of their time in the busy waters around Seattle, the San Juan Islands, and Vancouver, British Columbia, there is always a chance a spill could happen.

The Southern Residents are a small and social population of killer whales, so an oil spill could have major impacts on the entire population if they were in the wrong place at the wrong time.

We’ve learned from past experience with the 1989 Exxon Valdez oil spill that killer whales and other marine mammals don’t avoid oiled areas on their own and exposure to oil likely can affect their populations. New information on impacts from the 2010 Deepwater Horizon oil spill on bottlenose dolphins (a close relative of killer whales) gives us a better idea of how oil exposure can affect the health and reproduction of marine mammals.

Oil spills are a significant threat to the Southern Resident population, which totals less than 90 animals, and the 2008 recovery plan [PDF] calls for a response plan to protect them. We brought experts together in 2007 to help us identify tools and techniques to deter killer whales from oil and develop a response plan so that we’d be prepared in case a major oil spill does happen.

The Sound of Readiness

Killer whales are acoustic animals. They use sound to communicate with each other and find food through echolocation, a type of biosonar. Because sound is so important, using loud or annoying sounds is one way that we can try to keep the whales away from an area contaminated with oil. We brainstormed a variety of ideas based on experience with killer whales and other animals and evaluated a long list of ideas, including sounds, as well as more experimental approaches, such as underwater lights, air bubble curtains, and hoses.

After receiving lots of input and carefully evaluating each option, we developed an oil spill response plan for killer whales that includes three main techniques to deploy quickly if the whales are headed straight toward a spill. Helicopter hazing, banging pipes (oikomi pipes), and underwater firecrackers are on the short list of options. Here’s a little more about each approach:

  • Helicopters are often available to do surveillance of oil and look for animals when a spill occurs. By moving at certain altitudes toward the whales, a helicopter creates sound and disturbs the water’s surface, which can motivate or “haze” whales to move away from oiled areas.
  • Banging pipes, called oikomi pipes, are metal pipes about eight feet long which are lowered into the water and struck with a hammer to make a loud noise. These pipes have been used to drive or herd marine mammals. For killer whales, pipes were successfully used to help move several whales that were trapped in a freshwater lake in Alaska.
  • Underwater firecrackers can also be used to deter whales. These small explosives are called “seal bombs” because they were developed and can be used to keep seals and sea lions away [PDF] from fishing gear. These small charges were used in the 1960s and 1970s to help capture killer whales for public display in aquaria. Now we are using historical knowledge of the whales’ behavior during those captures to support conservation of the whales.

In addition, our plan includes strict safety instructions about how close to get and how to implement these deterrents in order to prevent injury of oil spill responders and the whales. In the case of an actual spill, the wildlife branch within the Incident Command (the official response team dealing with the spill, usually led by the Coast Guard) would direct qualified responders to implement the different techniques based on specific information about the oil and whales.

Planning in Practice

Several killer whales break the surface of Washington's Puget Sound.

Killer whales use sound to communicate with each other and find food through echolocation. That’s why NOAA’s plan for keeping these acoustic animals away from oil spills involves using sound as a deterrent. (NOAA)

After incorporating the killer whale response plan into our overall Northwest Area Contingency Plan for oil spills, I felt better but knew we still had some work to do.

Since finalizing the plan in 2009, we’ve been focused on securing equipment, learning more about the techniques, and practicing them during oil spill drills. Working with the U.S. Coast Guard and local hydrophone networks (which record underwater sound), we’ve flown helicopters over underwater microphones to record sound levels at different distances and altitudes.

With our partners at the Washington Department of Fish and Wildlife and the Island Oil Spill Association, we built several sets of banging pipes and have them strategically staged around Puget Sound. In 2013 we conducted a drill with our partners and several researchers to test banging pipes in the San Juan Islands. It takes practice to line up several small boats, coordinate the movement of the boats, and synchronize banging a set of the pipes to create a continuous wall of sound that will discourage whales from getting close to oil. We learned a few critical lessons to update our implementation plans and to incorporate into plans for future drills.

A large oil spill in Southern Resident killer whale habitat would be a nightmare. I’m so glad we have partners focused on preventing and preparing for oil spills, and it is good to know we have a plan to keep an oil spill from becoming a catastrophe for endangered killer whales. That knowledge helps me rest easier and focus on good news like the boom in killer whale calves born to mothers in Washington’s Puget Sound.

You can find more information on our killer whale response plan and our recovery program for Southern Resident killer whales.

Lynne Barre in front of icy waters and snowy cliffs.Lynne Barre is a Branch Chief for the Protected Resources Division of NOAA Fisheries West Coast Region. She is the Recovery Coordinator for Southern Resident killer whales and works on marine mammal and endangered species conservation and recovery.


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Alaska Updates Plan for Using Dispersants During Oil Spills

Humpback whale and seabirds at surface of Bering Sea with NOAA ship beyond.

By breaking crude oils into smaller droplets, chemical dispersants reduce the surface area of an oil slick as well as the threats to marine life at the ocean surface, such as whales and seabirds. (NOAA)

While the best way to deal with oil spills in the ocean is to prevent them in the first place, when they do happen, we need to be ready. Cleanup is difficult, and there are no magic remedies to remove all the oil. Most big oil spills require a combination of cleanup tools.

This week the Alaska Regional Response Team, an advisory council for oil spill responses in Alaska, has adopted a revised plan for one of the most controversial tools in the toolbox: Chemical dispersants.

How Dispersants Are Used in Oil Spills

Dispersants are chemical compounds which, when applied correctly under the right conditions, break crude oils into smaller droplets that mix down into the water column. This reduces not only the surface area of an oil slick but also the threats to marine life at the ocean surface. By making the oil droplets smaller, they become much more available to natural degradation by oil-eating microbes.

Dispersants are controversial for many reasons, notably because they don’t remove oil from the marine environment. Mechanical removal methods are always preferred, but we also know that during large oil spills, containment booms and skimmers can get overwhelmed and other pollution response tools may be necessary. This is a big concern especially in Alaska, where weather and remote locations increase the logistical challenges inherent in a large scale oil spill response.

Although dispersants get a lot of attention because of their extensive use after the 2010 Deepwater Horizon oil spill, they actually are used rarely during oil spills. In fact, dispersants have only been applied to about two dozen spills in the United States in the last 40 years. The only time they were tested during an actual spill in Alaska was during the Exxon Valdez oil spill in 1989.

Some oils like light and medium crude are often dispersible and others, like heavy fuel oils, often are not. In some cases dispersants have worked and in others they haven’t. The results of the Exxon Valdez testing were unclear and still subject to debate. So, why have a plan for something that is rarely used and may not be successful?

Probably the biggest reason is pragmatic. Dispersants work best on fresh, unweathered oil. Ideally, they should be applied to oil within hours or days of a spill. Because time is such a critical factor to their effectiveness, dispersants need to be stockpiled in key locations, along with the associated aircraft spraying and testing equipment. People properly trained to use that equipment need to be ready to go too.

A New Plan for Alaska

Airplane sprays dispersants over an oil slick in the Gulf of Mexico.

Although only used once in an Alaskan oil spill, dispersants have already been an approved oil spill response tool in the state for a number of years. This new plan improves the decision procedures and designates areas where dispersant use may be initiated rapidly. (U.S. Environmental Protection Agency)

Now, dispersants have already been an approved oil spill response tool in Alaska [PDF] for a number of years. This new plan improves the decision procedures and designates areas where dispersant use may be initiated rapidly while still requiring notification of the natural resource trustees, local and tribal governments, and other stakeholders before actual use.

Alaska’s new plan specifies all the requirements for applying dispersants on an oil spill in Alaskan waters and includes detailed checklists to ensure that if dispersants are used, they have a high probability of success.

The new plan sets up a limited preauthorization zone in central and western Alaska, and case-by-case procedures for dispersant use elsewhere in Alaska. The plan also recognizes that there are highly sensitive habitats where dispersant use should be avoided.

In addition, preauthorization for using dispersants exists only for oil spills that happen far offshore. Most states have similar preauthorization plans that allow dispersant use starting three nautical miles offshore. The new Alaska plan starts at 24 miles offshore.

We realize that even far offshore, there may be areas to avoid, which is why all of the spill response plans in central and western Alaska will be revised over the next two years. This will occur through a public process to identify sensitive habitats where dispersant use would be subject to additional restrictions.

Planning for the Worst, Hoping for the Best

As the NOAA representative to the Alaska Regional Response Team, I appreciate all of the effort that has gone into this plan. I am grateful we developed the many procedures through a long and inclusive planning process, rather than in a rush on a dark and stormy night on the way to an oil spill.

But I hope this plan will never be needed, because that will mean that a big oil spill has happened. Nobody wants that, especially in pristine Alaskan waters.

Any decision to use dispersants will need to be made cautiously, combining the best available science with the particular circumstances of an oil spill. In some cases, dispersants may not be the best option, but in other scenarios, there may be a net environmental benefit from using dispersants. Having the dispersants, equipment, plans, and training in place will allow us to be better prepared to make that critical decision should the time come.

At the same time, NOAA and our partners are continuing to research and better understand the potential harm and trades-offs of dispersant use following the Deepwater Horizon oil spill. We are participating in an ongoing effort to understand the state of the science on dispersants and their potential use in Arctic waters. (The University of New Hampshire is now accepting comments on the topic of dispersant efficacy and effectiveness.)

You can find Alaska’s new dispersant policy and additional information at the Alaska Regional Response Team website at www.alaskarrt.org.

For more information on our work on dispersants, read the April 2015 article, “What Have We Learned About Using Dispersants During the Next Big Oil Spill?” and July 2013 article, “Watching Chemical Dispersants at Work in an Oil Spill Research Facility.”


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Helping a 7-year-old Oceanographer Study Oil Spills in Washington’s Waters

A young boy drops wooden yellow cards off the side of a boat into water.

Dropping the first round of drift cards off a boat in Washington’s San Juan Islands, a kindergartner kicked off his experiment to study oil spills. (Used with permission of Alek)

One spring day in 2014, a shy young boy sidled up to the booth I was standing at during an open house hosted at NOAA’s Seattle campus. His blond head just peaking over the table, this then-six-year-old, Alek, accompanied by his mom and younger sister, proceeded to ask how NOAA’s oil spill trajectory model, GNOME, works.

This was definitely not the question I was expecting from a child his age.

After he set an overflowing binder onto the table, Alek showed me the printed-out web pages describing our oil spill model and said he wanted to learn how to run the model himself. He was apparently planning a science project that would involve releasing “drift cards,” small biodegradable pieces of wood marked with identifying information, into Washington’s Salish Sea to simulate where spilled oil might travel along this heavily trafficked route for oil tankers.

Luckily, Chris Barker, one of our oceanographers who run this scientific model, was nearby and I introduced them.

But that wasn’t my last interaction with this precocious, young oceanographer-in-training. Alek later asked me to serve on his science advisory committee (something I wish my middle school science fair projects had the benefit of having). I was in the company of representatives from the University of Washington, Washington State Department of Ecology, and local environmental and marine organizations.

Over the next year or so, I would direct his occasional questions about oil spills, oceanography, and modeling to the scientists in NOAA’s Office of Response and Restoration.

Demystifying the Science of Oil Spills

A hand-drawn map of oil tankers traveling from Alaska to Washington, a thank-you note on a post-it, and a hand-written card asking for donations.

Alek did a lot of work learning about how oil tankers travel from Alaska to Washington waters and about the threat of oil spills. He even fund-raised to cover the cost of materials for his drift cards. (NOAA)

According to the Washington Department of Ecology, the waters of the Salish Sea saw more than 7,000 journeys by oil tankers traveling to and from six oil refineries along its coast in 2013. Alek’s project was focused on Rosario Strait, a narrow eastern route around Washington’s San Juan Islands in the Salish Sea. There, he would release 400 biodegradable drift cards into the marine waters, at both incoming and outgoing tides, and then track their movements over the next four months.

The scientific questions he was asking in the course of his project—such as where spilled oil would travel and how it might affect the environment—mirror the types of questions our scientists and oil spill experts ask and try to answer when we advise the U.S. Coast Guard during oil spills along the coast.

As Alek learned, multiple factors influence the path spilled oil might take on the ocean, such as the oil type, weather (especially winds), tides, currents, and the temperature and salinity of the water. He attempted to take some of these factors into account as he made his predictions about where his drift cards would end up after he released them and how they would get there.

As with other drift card studies, Alek relied on people finding and reporting his drift cards when they turned up along the coast. Each drift card was stamped with information about the study and information about how to report it.

NOAA has performed several drift card studies in areas such as Hawaii, California, and Florida. One such study took place after the December 1976 grounding of the M/V Argo Merchant near Nantucket Island, Massachusetts, and we later had some of those drift cards found as far away as Ireland and France.

A Learning Experience

A young boy in a life jacket holding a yellow wooden card and sitting on the edge of a boat.

Alek released 400 biodegradable drift cards near Washington’s San Juan Islands in the Salish Sea, at both incoming and outgoing tides, and tracked their movements to simulate an oil spill. (Used with permission of Alek)

Of course, any scientist, young or old, comes across a number of challenges and questions in the pursuit of knowledge. For Alek, that ranged from fundraising for supplies and partnering with an organization with a boat to examining tide tables to decide when and where to release the drift cards and learning how to use Google Earth to map and measure the drift cards’ paths.

Only a couple weeks after releasing them, Alek began to see reports of his drift cards turning up in the San Juan Islands and even Vancouver Island, Canada, with kayakers finding quite a few of them.

As Alek started to analyze his data, we tried to help him avoid overestimating the area of water and length of coastline potentially affected by the simulated oil spill. Once released, oil tends to spread out on the water surface and would end up in patches on the shoreline as well.

Another issue our oceanographer Amy MacFadyen pointed out to Alek was that “over time the oil is removed from the surface of the ocean (some evaporates, some is mixed into the water column, etc.). So, the sites that it took a long time for the drift cards to reach would likely see less impacts as the oil would be much more spread out and there would be less of it.”

During his project, Alek was particularly interested in examining the potential impacts of an oil spill on his favorite marine organism, the Southern Resident killer whales (orcas) that live year-round in the Salish Sea but which are endangered. He used publicly available information about their movements to estimate where the killer whales might have intersected the simulated oil (the drift cards) across the Salish Sea.

Originally, Alek had hoped to estimate how many killer whales might have died as a result of a hypothetical oil spill in this area, but determining the impacts—both deadly and otherwise—of oil on marine mammals is a complicated matter. As a result, we advised him that there is too much uncertainty and not enough data for him to venture a guess. Instead, he settled on showing the number of killer whales that might be at risk of swimming through areas of simulated oil—and hence the killer whales that could be at risk of being affected by oil.

Ocean Scientist in Training

Google Earth view of the differing paths Alek's two drift card releases traveled around Washington's San Juan Islands and Canada's Vancouver Island.

A Google Earth view of the differing paths Alek’s two drift card releases traveled around Washington’s San Juan Islands and Canada’s Vancouver Island. Red represents the paths of drift cards released on an outgoing tide and yellow, the paths of cards released on an incoming tide. (Used with permission of Alek)

“I’d like to congratulate him on a successful drift card experiment,” said MacFadyen. “His results clearly show some of the features of the ocean circulation in this region.”

In a touching note in his final report, Alek dedicated his study to several great ocean scientists and explorers who came before him, namely, Sylvia Earle, Jacques Cousteau, William Beebe, and Rachel Carson. He was also enthusiastic in his appreciation of our help: “Thank you very very much for all of your help! I love what you do at NOAA. Maybe someday I will be a NOAA scientist!”

If you’re interested in learning more about Alek’s study and his results, you can visit his website www.oilspillscience.org, where you also can view a video summary of his project.


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Our Top 10 New Year’s Resolutions for 2016

2015 written on a sandy beach with an approaching wave.

So long, 2015. Hello, 2016!

Another year has gone by, and we’ve stayed plenty busy: responding to a leaking California pipeline, examining the issue of wrecked and abandoned ships, preparing a natural resource damage assessment and restoration plan for the Gulf of Mexico, and removing 32,201 pounds of marine debris from Hawaii’s Midway Atoll.

You can read more about what we accomplished in the last year, but keep in mind we have big goals for 2016 too. We’re aiming to:

  1. Be better models. This spring, we are planning to release an overhaul of our signature oil spill trajectory forecasting (GNOME) and oil weathering (ADIOS) models, which will be combined into one tool and available via an online interface for the first time.
  2. Tidy up. Our coasts, that is. In the next year, we will oversee marine debris removal projects in 17 states and territories, empowering groups to clean up coastal areas of everything from plastics to abandoned fishing gear.
  3. Use or lose. Nature and wildlife offer a lot of benefits to people, and we make use of them in a number of ways, ranging from recreational fishing to birdwatching to deep-seated cultural beliefs. In 2016 we’ll examine what we lose when nature and wildlife get harmed from pollution and how we calculate and make up for those losses.
  4. Get real. About plastic in the ocean, that is. We’ll be turning our eye toward the issue of plastic in the ocean, how it gets there, what its effects are, and what we can do to keep it out of the ocean.
  5. Explore more. We’ll be releasing an expanded, national version of our DIVER data management tool, which currently holds only Deepwater Horizon data for the Gulf of Mexico, allowing us and our partners to better explore and analyze ocean and coastal data from around the country.
  6. Get artistic. Through our NOAA Marine Debris Program, we are funding projects to create art from ocean trash to raise awareness of the issue and keep marine debris off our coasts and out of our ocean.
  7. Break ground on restoration. Finalizing the draft comprehensive restoration plan for the Gulf of Mexico, following the 2010 Deepwater Horizon oil spill, will bring us one step closer to breaking ground on many restoration projects over the next several years.
  8. App to it. We are working on turning CAMEO Chemicals, our popular database of hazardous chemicals, into an application (app) for mobile devices, making access to critical information about thousands of potentially dangerous chemicals easier than ever.
  9. Train up. We pride ourselves on providing top-notch training opportunities, and in 2016, we already have Science of Oil Spill classes planned in Mobile, Alabama, and Ann Arbor, Michigan (with more to come). Plus, we’ve introduced a brand-new Science of Chemical Releases class, designed to provide information and tools to better manage and plan for responses to chemical incidents.
  10. Get strategic. We are updating our five year strategic plan, aligning it with NOAA’s Ocean Service strategic priorities [PDF], which are coastal resilience (preparedness, response, and recovery), coastal intelligence, and place-based conservation.


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Why Is It So Hard to Count the Number of Animals Killed by Oil Spills?

Dead bird covered in oil next to spill containment boom on a beach.

Many animals directly killed by oil spills will never be found at all for a number of reasons. Even if people can find a dead animal carcass, it might be too decomposed to tell if oil killed it. (Department of Interior)

After an oil spill along the coast, the impacts might appear to be pretty obvious: oil on beaches, dead birds, oil-coated otters. When conducting a Natural Resource Damage Assessment, it’s our job to measure those environmental impacts and determine what kind of restoration—and how much—is needed to make up for those impacts.

But in general we don’t base those calculations solely on how many animals were observed dead on shorelines, because that would drastically underestimate the total number of animals killed by an oil spill.

Why?

Well, for starters, the length of shoreline where animals might wash up could be very long, isolated, or otherwise difficult to survey. For a large oil spill, imagine trying to study a place as expansive as the Gulf of Mexico. This body of water covers roughly 600,000 square miles and borders five states. Also, significant portions of the shore are wetlands with convoluted shorelines that make searching and finding animals much more difficult than on sandy beaches.

Let Me Count the Ways

Scientists records data on a dead dolphin on a beach.

Oil spills can have indirect effects that don’t necessarily kill animals and plants, at least, not right away, but those impacts can lead to death and health and reproductive problems months or years later. (Credit: Louisiana Department of Fisheries and Wildlife)

Trying to determine the total number of animals that died because of an oil spill offers multiple challenges. Quantifying these impacts to wildlife relies in part on people being able to find, record, and sometimes take samples of dead animal carcasses across an extended distance and length of time.

They then would need to tie those deaths to a particular oil spill, which is part of our responsibility as we assess the environmental harm after a spill. It’s also complicated by the fact that animals die every day for many reasons other than oil spills, due to changes in weather, food supplies, predation, background pollution, and disease.

This difficult undertaking has numerous limitations, and as a result, relying on counts of animal deaths alone can drastically underestimate the actual harm caused by a spill.

Graphic of oil spill in ocean near coast showing the multiple scenarios for the carcasses of animals killed by an oil spill. They include: Discovered carcasses (Of those carcasses that are found, most are too decomposed to determine the cause of death), remote strandings (Animals strand on remote shorelines that humans don't frequent), scavenging (Carcasses attract scavengers, such as sharks, birds, crabs, and others, that consume and remove evidence of dead animals), dying underwater (Some animals may die while underwater and disappear), decomposition (Hot weather causes carcasses to decay quickly in the water and on the shore), sinking (Carcasses may sink), and winds, currents, and distance from shore (These factors impact the movement of animals toward or away from shore).

The challenge of finding an animal that dies from an oil spill: Only a fraction of the turtles, dolphins, birds, fish, and other animals killed by an oil spill are ever found. (NOAA)

For example, even if people can find a dead animal carcass, it might be too decomposed to tell if oil killed it. But more likely are the scenarios where animals directly killed by oil will never be found at all because they:

  • Are eaten by predators or scavengers.
  • Die underwater.
  • Sink below the ocean surface.
  • Wash ashore in remote areas where people can’t or don’t often go.
  • Are carried out to the open ocean by winds and currents.
  • Decompose before people can observe them.
  • Are too tiny for people to easily observe after they die (e.g., young fish and crustaceans).

Late-Breaking Effects

To make things even more challenging, oil spills can have indirect effects that don’t outright kill animals and plants, at least, not right away. Dealing with exposure to oil can cause a number of damaging impacts, including lung disease (from inhaling oil vapors), stress hormone dysfunction, reduced growth, increased vulnerability to disease, heart failure and deformities in developing fish, and reproductive problems in animals such as dolphins and fish.

These types of effects can lead to other health impacts and sometimes eventually death, with the fallout felt across generations. Simply trying to count the number of dead animal carcasses found immediately after an oil spill would miss these deaths (or births that never happen) that can come months or even years afterward.

Seek and You May or May Not Find

Despite these challenges, it’s still useful to collect dead animal carcasses after an oil spill and use information gained from them to support other approaches for determining broader oil spill impacts.

One such approach takes into account several additional types of data, along with the observations of dead animals, to infer the likely true number of animals killed by an oil spill. These data include different animals’ estimated exposure to oil, health effects observed in laboratory and field studies, and basic information about animal behavior at different stages of life.

For instance, after the 2007 Cosco Busan oil spill in California’s San Francisco Bay, search teams recovered several thousand oiled birds, and additional studies were later performed to determine how many more dead birds were likely killed that were never seen or collected.

In one such study (known as a “Searcher Efficiency Study”), a study team randomly placed 107 real bird carcasses along San Francisco Bay shorelines over the course of three days, and teams were deployed to search for them and collect what they could find. It is surprisingly easy for searchers to miss dead birds on the beach since the animals blend in with other debris or beach wrack, can be hidden by small depressions, or be too far away to recognize.

Since the study team knew the actual number and locations of carcasses deployed for the study, the number that search teams collected provided a basis for calculating how many dead birds were likely missed by search teams during the actual Cosco Busan oil spill. This study determined that a two-person search team would find 68% of the dead bird carcasses on San Francisco Bay beaches.

More than a dozen other studies [PDF] were also performed after this oil spill, contributing additional data that went into the calculations of the total numbers and species of birds killed. Through this work, the actual number of birds killed by the spill was estimated to be 6,849, nearly two and a half times the number of birds actually collected during the Cosco Busan oil spill.

We commonly use several other methods to determine the magnitude of an oil spill’s effects on animals and plants, including studies of habitat changes, laboratory toxicity studies, and modeling.

Stay tuned because we plan to discuss these approaches more in-depth in the future. In the meantime, learn about the scientific processes we use to assess an oil spill’s environmental impacts at darrp.noaa.gov/science/our-scientific-process.


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What Was the Fate of Lake Erie’s Leaking Shipwreck, the Argo?

Two people on a boat inspect a diver in a full dive suit.

A diver, wearing a positive pressure dive suit, is inspected by his coworkers prior to conducting dive operations for the Argo response in Lake Erie, Nov. 24, 2015. Divers conducting operations during the Argo response are required to wear specialized dive suits designed for the utmost safety to the diver while ensuring flexibility, ease of decontamination, and chemical resistance. (U.S. Coast Guard)

At the end of October, we reported that our oil spill experts were helping the U.S. Coast Guard with a spill coming from the tank barge Argo in Lake Erie. The unusual twist in this case was that the leaking Argo was located at the bottom of the lake under approximately 40 feet of water. Nearly 80 years earlier, on October 20, 1937, this ship had foundered in a storm and sank in western Lake Erie.

At this point, the pollution response for the Argo is wrapping up, and we have more information about this shipwreck and the fate of its cargo.

For example, we knew that originally this ship was loaded with thousands of barrels of crude oil and benzol (an old commercial name for the chemical benzene), but after decades of sitting underwater, were the eight tanks holding them still intact? How much of the oil and chemical cargo was still inside them? What exactly was causing the discolored slicks on the lake surface? What was the threat to people and the environment from this pollution?

In Less Than Ship-Shape

Two hands place a label on a jar of oil.

A responder labels a sample of product for analysis extracted from the Lake Erie Barge Argo Nov. 11, 2015. NOAA was involved in coordinating environmental sampling and analysis of the leaking chemicals coming from this 1937 shipwreck. (U.S. Coast Guard)

Based on our previous work with NOAA’s Remediation of Underwater Legacy Environmental Threats (RULET) project, we had identified the Argo as a potential pollution threat in 2013. It was one of five potentially polluting wrecks identified in the Great Lakes. However, the exact location of the wreck was unknown, and the barge was thought to be on the Canadian side of the lake.

But in September 2015, the Cleveland Underwater Explorers located the vessel, which was confirmed to be in U.S. waters of Lake Erie and appeared from side-scan sonar survey imagery to be intact. Divers commissioned by the Coast Guard surveyed the wreck in October and found its eight cargo tanks were intact.

Yet they also observed something slowly leaking from a small rivet hole in the vessel’s structure. After sampling the leaking material, we now know that it was primarily benzene with traces of a light petroleum product.

Lighter the Load

Two responders carry a large tube next to pipe and holding tanks.

Responders aboard one of two work barges for the Lake Erie Barge Argo response prepare the receiving tanks in this Nov. 18, 2015 photo in preparation for lightering operations of the Argo. All chemicals and petroleum products were successfully removed from the wreck of the barge. (U.S. Coast Guard)

From late October through early December, we had a NOAA Scientific Support Coordinator and support team working with the Coast Guard’s response in Toledo, Ohio. One of our primary functions was advising the Coast Guard on chemical hazards (e.g., benzene is known to cause cancer). For example, we were modeling where the chemicals would travel through the air and across the water surface if a sizable release were to occur during the wreck’s salvage operations.

Responders finished lightering operations, which removed all remaining chemicals and oil from the barge to another vessel, on December 1. Based on sampling, we believe any residual chemical traces in the sediment surrounding the wreck will continue to break down naturally and do not pose a threat to people or aquatic life in the vicinity of the wreck.

Over the course of the response, NOAA provided almost 30 trajectory forecasts for surface slicks, daily weather forecasts, and data management support via our online response mapping application, ERMA, which displayed NOAA charts and weather, NOAA and Canadian spill trajectories, spill modeling and aerial survey information, spill response plans, and data for environmentally sensitive habitats and species in the area.

NOAA, along with state and federal partners, also managed the development of environmental monitoring, water sampling, sediment sampling, and waste disposal plans for the Argo’s response. In addition, the NOAA Great Lakes Environmental Research Laboratory provided science and logistical support and the NOAA Office of National Marine Sanctuaries provided key historical and archival research on the vessel and cargo.

Check out our special series that explores the issues of sunken, abandoned, and derelict vessels—covering everything from when they become maritime heritage sites to how we deal with those that turn into polluting eyesores.