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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Using Big Data to Restore the Gulf of Mexico

This is a post by Ocean Conservancy’s Elizabeth Fetherston.

If I ask you to close your eyes and picture “protection for marine species,” you might immediately think of brave rescuers disentangling whales from fishing gear.

Or maybe you would imagine the army of volunteers who seek out and protect sea turtle nests. Both are noble and worthwhile endeavors.

But 10 years of ocean conservation in the southeast United States has taught me that protecting marine species doesn’t just look like the heroic rescue of adorable species in need.

I’ve learned that it also looks like the screen of 1s and 0s from the movie The Matrix.

Let me explain.

Much of what goes on with marine life in the Gulf of Mexico—and much of the rest of the ocean—is too dark and distant to see and measure easily or directly. Whales and fish and turtles move around a lot. This makes it difficult to collect information on how many there are in the Gulf and how well those populations are doing.

In order to assess their health, you need to know where these marine species go, what they eat, why they spend time in certain areas (for food, shelter, or breeding?), and more. This information may come from a number of places—state agencies, universities, volunteer programs, you name it—and be stored in a number of different file formats.

Until recently, there was no real way to combine all of these disparate pixels of information into a coherent picture of, for instance, a day in the life of a sea turtle. DIVER, NOAA’s new website for Deepwater Horizon assessment data, gives us the tools to do just that.

Data information and integration systems like DIVER put all of that information in one place at one time, allowing you to look for causes and effects that you might not have ever known were there and then use that information to better manage species recovery. These data give us a new kind of power for protecting marine species.

Of course, this idea is far from new. For years, NOAA and ocean advocates have both been talking about a concept known as “ecosystem-based management” for marine species. Put simply, ecosystem-based management is a way to find out what happens to the larger tapestry if you pull on one of the threads woven into it.

For example, if you remove too many baitfish from the ecosystem, will the predatory fish and wildlife have enough to eat? If you have too little freshwater coming through the estuary into the Gulf, will nearby oyster and seagrass habitats survive? In order to make effective and efficient management decisions in the face of these kinds of complex questions, it helps to have all of the relevant information working together in a single place, in a common language, and in a central format.

Screenshot of DIVER tool showing map of Gulf of Mexico and list of data results in a table.

A view of the many sets of Gulf of Mexico environmental data that the tool DIVER can bring together. (NOAA)

So is data management the key to achieving species conservation in the Gulf of Mexico? It just might be.

Systems like DIVER are set up to take advantage of quantum leaps in computing power that were not available to the field of environmental conservation 10 years ago. These advances give DIVER the ability to accept reams of diverse and seemingly unrelated pieces of information and, over time, turn them into insight about the nature and location of the greatest threats to marine wildlife.

The rising tide of restoration work and research in the Gulf of Mexico will bring unprecedented volumes of data that should—and now can—be used to design and execute conservation strategies with the most impact for ocean life in our region. Ocean Conservancy is excited about the opportunity for systems like DIVER to kick off a new era in how we examine information and solve problems.

Elizabeth Fetherston is a Marine Restoration Strategist with Ocean Conservancy. She is based in St. Petersburg, Florida and works to ensure restoration from the Deepwater Horizon oil disaster is science-based, integrated across political boundaries, fully funded, and inclusive of offshore Gulf waters where the spill originated.


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Who Thinks Crude Oil Is Delicious? These Ocean Microbes Do

This is a post by Dalina Thrift-Viveros, a chemist with NOAA’s Office of Response and Restoration.

Edge of oil slick at ocean surface.

There are at least seven species of ocean bacteria that can survive by eating oil and nothing else. However, usually only a small number of oil-eating bacteria live in any given part of the ocean, and it takes a few days for their population to increase to take advantage of their abundant new food source during an oil spill. (NOAA)

Would you look at crude oil and think, “Mmm, tasty…”? Probably not.

But if you were a microbe living in the ocean you might have a different answer. There are species of marine bacteria in several families, including Marinobacter, Oceanospiralles, Pseudomonas, and Alkanivorax, that can eat compounds from petroleum as part of their diet. In fact, there are at least seven species of bacteria that can survive solely on oil [1].

These bacteria are nature’s way of removing oil that ends up in the ocean, whether the oil is there because of oil spills or natural oil seeps. Those of us in the oil spill response community call this biological process of removing oil “biodegradation.”

What Whets Their Oily Appetites?

Communities of oil-eating bacteria are naturally present throughout the world’s oceans, in places as different as the warm waters of the Persian Gulf [2] and the Arctic conditions of the Chukchi Sea north of Alaska [3].

Each community of bacteria is specially adapted for the environment where it is living, and studies have found that bacteria consume oil most quickly when they are kept in conditions similar to their natural environments [4]. So that means that if you took Arctic bacteria and brought them to an oil spill in the Gulf of Mexico, they would not eat the oil as quickly as the bacteria that are already living in the Gulf. You would get the same result in the reverse case, with the Arctic bacteria beating out the Gulf bacteria at an oil spill in Alaska.

Other factors that affect how quickly bacteria degrade oil include the amount of oxygen and nutrients in the water, the temperature of the water, the surface area of the oil, and the kind of oil that they are eating [4][5][6]. That means the bacteria that live in a given area will consume the oil from a spill in the summer more quickly than a spill in the winter, and will eat light petroleum products such as gasoline or diesel much more quickly than heavy petroleum products like fuel oil or heavy crude oil.

Oil-eating microbes fluorescing in a petri dish.

This bacteria, fluorescing under ultraviolet light in a petri dish, is Pseudomonas aeruginosa. It has been used during oil spills to break down the components of oil. (Credit: Wikimedia user Sun14916/Creative Commons Attribution-ShareAlike 3.0 Unported license)

Asphalt, the very heaviest component of crude oil, is actually so difficult for bacteria to eat that we can use it to pave our roads without worrying about the road rotting away.

What About During Oil Spills?

People are often interested in the possibility of using bacteria to help clean up oil spills, and most oil left in the ocean long enough is consumed by bacteria.

However, most oil spills last only a few days, and during that time other natural “weathering” processes, such as evaporation and wave-induced breakup of the oil, have a much bigger effect on the appearance and location of the oil than bacteria do. This is because there are usually only a small number of oil-eating bacteria in any given part of the ocean, and it takes a few days for their population to increase to take advantage of their abundant new food source.

Because of this lag time, biodegradation was not originally included in NOAA’s oil weathering software ADIOS. ADIOS is a computer model designed to help oil spill responders by predicting how much of the oil will stay in the ocean during the first five days of a spill.

However, oil spills like the 2010 Deepwater Horizon well blowout, which released oil for about three months, demonstrate that there is a need for a model that can tell us what would happen to the oil over longer periods of time. My team in the Emergency Response Division at NOAA’s Office of Response and Restoration has recognized that. As a result, version 3 of ADIOS, due to be released later in 2015, will take into account biodegradation.

My team and I used data published in scientific journals on the speed of oil biodegradation under different conditions to develop an equation that can predict how fast the components of oil will be consumed, and how the speed of this process can change based on the surface area-to-mass ratio of the oil and the climate it is in. A report describing the technical details of the model will be published in the upcoming Proceedings of the Arctic and Marine Oilspill Program Technical Seminar, which will be released after the June conference.

Including oil biodegradation in our ADIOS software will provide oil spill responders with an even better tool to help them make decisions about their options during a response. As part of the team working on this project, it has provided me with a much greater appreciation for the important role that oil-eating bacteria play in the long-term effort to keep our oceans free of oil.

I know I’m certainly glad they think oil is delicious.

Dalina Thrift-ViverosDalina Thrift-Viveros is a Seattle-based chemist who has been providing chemistry expertise for Emergency Response Division software projects and spill responders since 2011, when she first started working with NOAA and Genwest. When she is not involved in chemistry-related activities, Dalina sings with the rock band Whiskey River and plays sax with her jazz group, The Paul Engstrom Trio.

Literature cited

[1] Yakimov, M.M., K.N. Timmis, and P.N. Golyshin. “Obligate oil-degrading marine bacteria,” Current Opinion in Biotechnology, 2007, 18(3), pp. 257-266.

[2] Hassanshahian, M., G. Emtiazi, and S.Cappello. “Isolation and characterization of crude-oil-degrading bacteria from the Persian Gulf and the Caspian Sea,” Marine Pollution Bulletin, 2012, 64, pp. 7–12.

[3] McFarlin, K.M., R.C. Prince, R. Perkins, and M.B. Leigh. “Biodegradation of Dispersed Oil in Arctic Seawater at -1°C,” PLoS ONE, 2014, 9:e84297, pp. 1-8.

[4] Atlas, R.M. “Petroleum Biodegradation and Oil Spill Bioremediation,” Marine Pollution Bulletin, 1995, 31, pp. 178-182.

[5] Atlas, R.M. and T.C. Hazen. “Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills in U.S. History,” Environmental Science & Technology, 2011, 45, pp. 6709-6715.

[6] Head, I.M., D.M. Jones, and W.F.M. Röling, “Marine microorganisms make a meal of oil,” Nature Reviews Microbiology, 2006, 4, pp. 173-182.


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Like a Summer Blockbuster, Oil Spills and Hurricanes Can Take the Nation by Storm

Wrecked sailboats and debris along a dock after a hurricane.

The powerful wind and waves of a hurricane can damage vessels, releasing their fuel into coastal waterways. (NOAA)

From Twister and The Perfect Storm to The Day After Tomorrow, storms and other severe weather often serve as the dramatic backdrop for popular movies. Some recent movies, such as the Sharknado series, even combine multiple fearsome events—along with a high degree of improbability—when they portray, for example, a hurricane sweeping up huge numbers of sharks into twisters descending on a major West Coast city.

But back in the world of reality, what could be worse than a hurricane?

How about a hurricane combined with a massive oil spill? It’s not just a pitch for a new movie. Oil spills actually are a pretty common outcome of powerful storms like hurricanes.

There are a couple primary scenarios involving oil spills and hurricanes. The first is a hurricane causing one or more oil spills, which is what happened during Hurricane Katrina in 2005 and after Hurricane Sandy in 2012. These kinds of oil spills typically result from a storm’s damage to coastal oil facilities, including refineries, as well as vessels being damaged or sunken and leaking their fuel.

The second, far less common scenario is a hurricane blowing in during an existing oil spill, which is what happened during the 2010 Deepwater Horizon oil spill.

Hurricane First, Then Oil Spills

Stranded and wrecked vessels are one of the iconic images showing the aftermath of a hurricane. In most cases those vessels have oil on board. And don’t forget about all the cars that get flooded. Each of these sources may contain relatively small amounts of fuel, but hurricanes can cause big oil spills too.

Additional damage is often caused by the storm surge, as big oil and chemical storage tanks can get lifted off their foundations (or sheared off in the case of the picture below).

A damaged boat setting on a  fuel dock.

A boat, displaced and damaged in the aftermath of Hurricane Katrina, in late summer of 2005 in the Gulf of Mexico, an area frequented by both hurricanes and oil spills. (NOAA)

Hurricanes Katrina and Rita in 2005 passed through the center of the Gulf of Mexico oil industry and caused dozens of major oil spills and thousands of small spills.

One of the largest stemmed from the Murphy Oil refinery in St. Bernard Parish, Louisiana. Dikes surrounding the oil tanks at the refinery were full from flood waters, so when a multi-million gallon tank failed, oil flowed easily into a nearby neighborhood, leaving oil on thousands of homes and businesses already reeling from the flood waters.

Hurricanes can also create navigation hazards that result in later spills. Hurricane Rita, hitting the Gulf in September 2005, sank several offshore oil platforms. While some were recovered, others were actually left missing. Several months later, the tank barge DBL 152 “found” one of these missing rigs, spilling nearly 2 million gallons of thick slurry oil after striking the sunken and displaced platform hiding below the ocean surface.

A large ship on its side, leaking dark oil on the ocean surface.

In November 2005, tank barge DBL 152 struck the submerged remains of a pipeline service platform that collapsed a few months earlier during Hurricane Rita. The double-hulled barge was carrying approximately 5 million gallons of slurry oil, a type of oil denser than seawater, which meant as the thick oil poured out of the barge, it sank to the seafloor. (Entrix)

Oil Spills and Then a Hurricane Hits

So what happens if a hurricane hits an existing oil spill?

This was a big concern during the summer of 2010 in the Gulf of Mexico. There was an ever-growing slick on the ocean surface, oil already on the shore, and lots of response equipment and personnel scattered across the Gulf cleaning up the Deepwater Horizon spill.

There was a lot of speculation as to what might happen as hurricane season began. Hurricane Alex, a relatively small storm, was the first test. The first impact came days before the storm, as response vessels evacuated the area. Hurricane Alex halted response efforts such as skimming and burning for several days. Hundreds of miles of oil booms protecting the shoreline were displaced by the growing surf.

As the hurricane passed through, floating oil was quickly dispersed by the powerful winds and waves, and the same wave energy buried, uncovered, and moved oil on the shore or in submerged mats of oil near the shoreline. Some oil was likely carried inland by sea spray and flood waters from the storm surge. Oil dissolved in the water column near the surface became even more dispersed, but the deep waters of the Gulf were well out of reach of the stormy commotion at the surface, and the leaking wellhead continued to gush.

But the Deepwater Horizon spill wasn’t the only time hurricanes have butted heads with a massive spill. In 1979, Mexico’s Ixtoc I well blowout in the southern Gulf of Mexico was hit by Hurricane Henri. The main impact of the hurricane’s winds was to dilute and weather the floating oil.

In some places along the Texas coast, beached oil was washed over the barrier islands into the bays behind them, while in other areas stranded oil was buried by clean sand. Many of these oiled areas were reworked a year later when Hurricane Allen battered the coast.

Preventing oil spills is a part of preparing for hurricanes. Coastal oil facilities and vessel owners do their best to batten down the hatches and get their vessels out of harm’s way, but we know that spills may still happen. Atlantic hurricane season, which runs from June 1 to November 30, is a busy time for those of us in oil spill response, and we breathe a sigh of relief when hurricane season ends—just in time for winter storm season to begin.


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Latest NOAA Study Ties Deepwater Horizon Oil Spill to Spike in Gulf Dolphin Deaths

Group of dolphin fins at ocean surface.

A study published in the journal PLOS ONE found that an unusually high number of dead Gulf dolphins had what are normally rare lesions on their lungs and hormone-producing adrenal glands, which are associated with exposure to oil compounds. (NOAA)

What has been causing the alarming increase in dead bottlenose dolphins along the northern Gulf of Mexico since the Deepwater Horizon oil spill in the summer of 2010? Independent and government scientists have found even more evidence connecting these deaths to the same signs of illness found in animals exposed to petroleum products, as reported in the peer-reviewed online journal PLOS ONE.

This latest study uncovered that an unusually high number of dead Gulf dolphins had what are normally rare lesions on their lungs and hormone-producing adrenal glands.

The timing, location, and nature of the lesions support that oil compounds from the Deepwater Horizon oil spill caused these lesions and contributed to the high numbers of dolphin deaths within this oil spill’s footprint.

“This is the latest in a series of peer-reviewed scientific studies, conducted over the five years since the spill, looking at possible reasons for the historically high number of dolphin deaths that have occurred within the footprint of the Deepwater Horizon spill,” said Dr. Teri Rowles, one of 22 contributing authors on the paper, and head of NOAA’s Marine Mammal Health and Stranding Response Program, which is charged with determining the causes of unusual mortality events.

“These studies have increasingly pointed to the presence of petroleum hydrocarbons as being the most significant cause of the illnesses and deaths plaguing the Gulf’s dolphin population,” said Dr. Rowles.

A System out of Balance

In this study, one in every three dead dolphins examined across Louisiana, Mississippi and Alabama had lesions affecting their adrenal glands, resulting in a serious condition known as “adrenal insufficiency.” The adrenal gland produces hormones—such as cortisol and aldosterone—that regulate metabolism, blood pressure and other bodily functions.

“Animals with adrenal insufficiency are less able to cope with additional stressors in their everyday lives,” said Dr. Stephanie Venn-Watson, the study’s lead author and veterinary epidemiologist at the National Marine Mammal Foundation, “and when those stressors occur, they are more likely to die.”

Earlier studies of Gulf dolphins in areas heavily affected by the Deepwater Horizon oil spill found initial signs of this illness in a 2011 health assessment of dolphins living in Barataria Bay, Louisiana. NOAA scientists Dr. Rowles and Dr. Lori Schwacke spoke about the results of this health assessment in a 2013 interview:

“One rather unusual condition that we noted in many of the Barataria Bay dolphins was that they had very low levels of some hormones (specifically, cortisol) that are produced by the adrenal gland and are important for a normal stress response.

Under a stressful condition, such as being chased by a predator, the adrenal gland produces cortisol, which then triggers a number of physiological responses including an increased heart rate and increased blood sugar. This gives an animal the energy burst that it needs to respond appropriately.

In the Barataria Bay dolphins, cortisol levels were unusually low. The concern is that their adrenal glands were incapable of producing appropriate levels of cortisol, and this could ultimately lead to a number of complications and in some situations even death.”

Swimming with Pneumonia

Ultrasounds showing a normal dolphin lung, compared to lungs with mild, moderate, and severe lung disease.

Ultrasounds showing a normal dolphin lung, compared to lungs with mild, moderate, and severe lung disease. These conditions are consistent with exposure to oil compounds and were found in bottlenose dolphins living in Barataria Bay, Louisiana, one of the most heavily oiled areas during the Deepwater Horizon oil spill. (NOAA)

In addition to the lesions on adrenal glands, the scientific team discovered that more than one in five dolphins that died within the Deepwater Horizon oil spill footprint had a primary bacterial pneumonia. Many of these cases were unusual in severity, and caused or contributed to death.

Drs. Rowles and Schwacke previously had observed significant problems in the lungs of dolphins living in Barataria Bay. Again, in 2013, they had noted, “In some of the animals, the lung disease was so severe that we considered it life-threatening for that individual.”

In other mammals, exposure to petroleum-based polycyclic aromatic hydrocarbons, known as PAHs, through inhalation or aspiration of oil products can lead to injured lungs and altered immune function, both of which can increase an animal’s susceptibility to primary bacterial pneumonia. Dolphins are particularly susceptible to inhalation effects due to their large lungs, deep breaths, and extended breath hold times.

Learn more about NOAA research documenting the impacts from the Deepwater Horizon oil spill and find more stories reflecting on the five years since this oil spill.


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NOAA Launches New Data Management Tool for Public Access to Deepwater Horizon Oil Spill Data

Two people launch a water column sampling device off the side of a ship.

Launching a device to take measurements in the water column during the 2010 Deepwater Horizon oil spill. NOAA built the online tool DIVER to organize and provide access to these scientific data and the many others collected in the wake of the spill. (NOAA)

A flexible new data management tool—known as DIVER and developed by NOAA to support the Natural Resource Damage Assessment (NRDA) for the 2010 Deepwater Horizon oil spill—is now available for public use. DIVER stands for “Data Integration, Visualization, Exploration and Reporting,” and it can be accessed at https://dwhdiver.orr.noaa.gov.

DIVER was developed as a digital data warehouse during the Deepwater Horizon oil spill response effort and related damage assessment process, which has required collecting and organizing massive amounts of scientific data on the environmental impacts of the spill.

The tool serves as a centralized data repository that integrates diverse environmental data sets collected from across the Gulf of Mexico ecosystem. It allows scientists from different organizations and laboratories located across the country to upload field data, analyses, photographs, and other key information related to their studies in a standardized format. DIVER thus brings together all of that validated information into a single, web-based tool.

In addition, DIVER provides unprecedented flexibility for filtering and downloading validated data collected as part of the ongoing damage assessment efforts for the Gulf of Mexico. The custom query and mapping interface of the tool, “DIVER Explorer,” provides both a data filter and review tools, which allow users to refine how they look for data and explore large data sets online. Query results are presented in an interactive dashboard, with a map, charts, table of results, metadata (data about the data), and sophisticated options for exporting the data.

View of DIVER Explorer map and query results for environmental impact data in the Gulf of Mexico.

A view of DIVER Explorer query results shown in an interactive dashboard. (NOAA)

In addition to the DIVER Explorer query tools, this website presents a detailed explanation of our data management approach, an explanation of field definitions and codes used in the data warehouse, and a robust help section.

Currently, DIVER provides access to nearly 4 million validated results of analytical chemistry from over 50,000 samples of water, tissue, oil, and sediment collected by federal, state, academic, and nongovernmental organizations to support the Deepwater Horizon damage assessment. As additional data sets become publicly available they will be accessible through the DIVER Explorer tool.

Read the announcement of this tool’s public launch from the NOAA website.


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Five Years After Deepwater Horizon, How Is NOAA Preparing for Future Oil Spills?

The Deepwater Horizon Oil Spill: Five Years Later

This is the ninth and final story in a series of stories over the past month looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

Oil in a boat wake on the ocean surface.

Keeping up with emerging technologies and changing energy trends helps us become better prepared for the oil spills of tomorrow, no matter where that may take us. (NOAA)

When the Exxon Valdez tanker ran aground in Alaska and spilled nearly 11 million gallons of crude oil in 1989, the world was a very different place. New laws, regulations, and technologies followed that spill, meaning future oil spills—though they undoubtedly would still occur—would do so in a fundamentally different context.

This was certainly the case by 2010 when the Deepwater Horizon oil rig suffered an explosion caused by a well blowout in the Gulf of Mexico. Tankers transporting oil have become generally safer since 1989 (thanks in part to now-required double hulls), and in 2010, the new frontier in oil production—along with new risks—was located at a wellhead nearly a mile under the ocean surface.

Since that fateful April day in 2010, NOAA has responded to another 400 oil and chemical incidents. Keeping up with emerging technologies and changing energy trends helps us become better prepared for the oil spills of tomorrow, whether they stem from a derailed train carrying particularly flammable oil, a transcontinental pipeline of diluted oil sands, or a cargo ship passing through the Arctic’s icy but increasingly accessible waters.

So how is NOAA’s Office of Response and Restoration preparing for future oil spills?

The Bakken Boom

Crude oil production from North Dakota’s Bakken region has more than quadrupled [PDF] since 2010, and responders must be prepared for spills involving this lighter oil (note: not all oils are the same).

Bakken crude oil is highly flammable and evaporates quickly in the open air. Knowing the chemistry of this oil can help guide decisions about how to respond to spills of Bakken oil. As a result, we’ve added Bakken as one of the oil types in ADIOS, our software program which models what happens to spilled oil over time. Now, responders can predict how much oil naturally disperses, evaporates, or remains on the water’s surface using information customized for Bakken’s unique chemistry.

We’ve also been collaborating across the spill response community to boost preparedness for these types of oil spills. Earlier this year, NOAA worked with the National Response Team to teach responders about how to deal with Bakken crude oil spills, with a special emphasis on health and safety.

The increase of Bakken crude poses another challenge to the nation: spills from oil-hauling trains. There are few ways to move Bakken crude from wells in North Dakota to refiners and consumers across the country. To keep up with the demand, producers have turned to rail transport as a quick alternative. In 2010, rail moved less than five million tons of crude petroleum. By 2013, that number had jumped to nearly 40 million.

NOAA typically responds to marine spills, but our scientific experience also proves useful when oil spills into a navigable river, as can happen when a train derails. To help answer response questions for waterways at risk, we’re adding even more data to our tools for spill responders. Ongoing updates to the Environmental Response Management Application (ERMA), our online mapping tool for environmental response data, illustrate the intersection of railroads and sensitive habitats and species, which might be affected by a spill from a train carrying oil.

Our Neighbor to the North

Oil imports from Canada, where oil sands (also known as tar sands) account for almost all of the country’s oil, have surged. Since 2010 Canadian oil imports have increased more than 40 percent.

Oil sands present another set of unique challenges. This variety is a thick, heavy crude oil (bitumen), which has to be diluted with a thinner type of oil to allow it to flow through a pipeline for transport. The resulting product is known as diluted bitumen, or dilbit.

Because oil sands are a mixture of products, it’s not completely clear how they react in the environment. When this product is released into water, the oils can separate quickly between lighter and heavier parts. As such, responders might have to worry about both lighter components vaporizing into toxic fumes in the air and heavier oil components potentially sinking down into the water column or bottom sediments, becoming more difficult to clean up. This also means that bottom-dwelling organisms may be more vulnerable to spills of oil sands than other types of oils.

As our experts work to assess the impacts from oil sands spills (including the 2010 Enbridge pipeline spill in Michigan), their studies both inform restoration for past spills and help guide response for the next spill. We’ve been working with the response and restoration community around the country to incorporate these lessons into spill response, including at recent meetings of the West Coast Joint Assessment Team and the International Spill Control Organization.

Even Further North

As shrinking summer sea ice opens shipping routes and opportunities for oil and gas production in the Arctic, the risk of an oil spill increases for that region. By 2020, up to 40 million tons per year of oil and gas are expected to travel the Northern Sea route through the Arctic Ocean.

Responding to oil spills in the Arctic will not be easy. Weather can be harsh, even in August. Logistical support is limited, and so is baseline science. Yet in the last five years, NOAA’s Office of Response and Restoration has made leaps in Arctic preparedness. For example, since 2010, we launched Arctic ERMA, a version of our interactive response data mapping tool customized for the region, and released Arctic Ephemeral Data Guidelines, a series of guidelines for collecting high-priority, time-sensitive data in the Arctic after an oil spill. But we still have plenty of work ahead of us.

Ship breaking ice in Arctic waters.

The U.S. Coast Guard Cutter Healy breaks ice in Arctic waters. A ship like this would be the likely center of operations for an oil spill in this remote and harsh region. (NOAA)

During a spill, we predict where oil is going, but Arctic conditions change the way oil behaves compared with warmer waters. Cold temperatures make oil more viscous (thick and slow-flowing), and in a spill, oil may be trapped in, on, and under floating sea ice, further complicating predictions of its movement.

We’ve been working to overcome this challenge by improving our models of oil movement and weathering in icy waters and researching response techniques and oil behavior to close gaps in the science. This May, we also find ourselves in a new role as the United States takes chairmanship of the Arctic Council. Amy Merten of NOAA’s Office of Response and Restoration will chair the Arctic Council’s Emergency Prevention, Preparedness and Response Working Group, where we hope to continue international efforts to boost Arctic spill preparedness.

Expecting the Unexpected

After decades of dealing with oil spills, we know one thing for certain—we have to be ready for anything.

In the last five years, we’ve responded to spills from the mangroves of Bangladesh to the banks of the Ohio River. These spills have involved Bakken crude, oil sands, and hazardous chemicals. They have resulted from well blowouts, leaking pipelines, derailed trains, grounded ships, storms, and more. In fact, one of the largest spills we’ve responded to since Deepwater Horizon involved 224,000 gallons of molasses released into a Hawaiian harbor.

Whatever the situation, it’s our job to provide the best available science for decisions. NOAA has more than 25 years of experience responding to oil spills. Over that time, we have continued to fine-tune our scientific understanding to better protect our coasts from this kind of pollution, a commitment that extends to whatever the next challenge may bring.


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What Have We Learned About Using Dispersants During the Next Big Oil Spill?

The Deepwater Horizon Oil Spill: Five Years Later

This is the eighth 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 U.S. Air Force plane drops an oil-dispersing chemical onto an oil slick on the Gulf of Mexico

A U.S. Air Force plane drops an oil-dispersing chemical onto an oil slick on the Gulf of Mexico May 5, 2010, as part of the Deepwater Horizon response effort. (NOAA)

Five years ago, in the middle of the response to the Deepwater Horizon oil spill, I was thrown into a scientific debate about the role of chemical dispersants in response to the spill. Dispersants are one of those things that are talked about a lot in the context of oil spills, but in reality used pretty rarely. Over my more than 20 years in spill response, I’ve only been involved with a handful of oil spills that used dispersants.

But the unprecedented use of chemical dispersants on and below the ocean’s surface during the Deepwater Horizon oil spill raised all sorts of scientific, public, and political questions. Questions about both their effectiveness in minimizing impacts from oil as well as their potential consequences for marine life in the Gulf of Mexico.

Did we understand how the ingredients and components of the dispersants behave? How toxic are they? What are the potential risks of dispersants and do they outweigh the benefits?

We knew the flood of questions wouldn’t end when the gushing oil well was capped; they would only intensify the next time there was a significant oil spill in U.S. waters. NOAA, as the primary scientific adviser to the U.S. Coast Guard, would need to keep abreast of the surge of new information and be prepared to answer those questions. Five years later, we know a lot more, but many of the scientific, public, and policy questions remain open to debate.

What Are Dispersants?

Dispersants are a class of chemicals specifically designed to remove oil from the water surface. One commonly used brand name is Corexit, but there are dozens of different dispersant mixtures (see this list of all the products available for use during an oil spill).

They work by breaking up oil slicks into lots of small droplets, similar to how dish detergent breaks up the greasy mess on a lasagna pan. These tiny droplets have a high surface area-to-volume ratio, making them easier for oil-eating microbes to break them down (through the process of biodegradation). Their small size also makes the oil droplets less buoyant, allowing them to scatter throughout the water column more easily.

Why Does Getting Oil off the Ocean Surface Matter?

Oil slicks on the water surface are particularly dangerous to seabirds, sea turtles, marine mammals, sensitive early life stages of fish (e.g., fish eggs and embryos), and intertidal resources (such as marshes and beaches and all of the plants and animals that live in those habitats). Oil, in addition to being toxic when inhaled or ingested, interferes with birds’ and mammals’ ability to stay waterproof and maintain a normal body temperature, often resulting in death from hypothermia. Floating oil can drift long distances and then strand on shorelines, creating a bigger cleanup challenge.

However, applying dispersants to an oil slick instead shifts the possibility of oil exposure to animals living in the water column beneath the ocean surface and on the sea floor. We talk about making a choice between either protecting shorelines and surface-dwelling animals or protecting organisms in the water column.

But during a large spill like the Deepwater Horizon, this is a false choice. No response technology is 100 percent effective, so it’s not either this or that; it’s how much of each? If responders do use dispersants, some oil will still remain on the surface (or reach the surface in the case of subsurface dispersants), and if they don’t use dispersants, some oil will still naturally mix into or remain in the water column.

Why Don’t We Just Clean up Oil with Booms and Skimmers?

Cleaning up oil with mechanical response methods like skimmers is preferable because these vessels actually remove the mess from the environment by skimming and collecting oil off the water surface. And in most spills, that is all we use. There are thousands of small and medium-sized spills annually, and mechanical cleanup is the norm for these incidents.

But these methods, known as “mechanical recovery,” can only remove some of the oil. Under ideal (rather than normal) circumstances, skimmers can recover—at best—only around 40 percent of an oil spill. During the Deepwater Horizon oil spill response, skimmers only managed to recover approximately 3 percent of the oil released.

Dispersants generally are only considered when mechanical cleanup would be swamped or is considered infeasible. During a big spill, mechanical recovery may only account for a small percentage of the oil. Booms (long floating barriers used to contain or soak up oil) and skimmers don’t work well in rough seas and take more time to deploy. Booms also require constant maintenance or they can become moved around by wind and waves away from their targeted areas. If they get washed onto shore, booms can cause significant damage, particularly in sensitive areas such as marshes and wetlands.

Aircraft spraying dispersant are able to treat huge areas of water quickly while a skimmer moves very slowly, only one to two miles per hour. In the open ocean spilled oil can spread as fast, or faster, than the equipment trying to corral it.

Isn’t There Something Better?

Chemical product label for Corexit dispersant.

Dispersants, such as Corexit, are a class of chemicals specifically designed to remove oil from the water surface by breaking up oil slicks into lots of small droplets. (NOAA)

Well, researchers are trying to develop more effective response tools, including safer dispersants. And the questions surrounding the potential benefits and risks of using dispersants in the Gulf of Mexico have led to substantial research in the Gulf and other waters at risk from spills, including the Arctic. That research is ongoing, and answering one question usually leads to several more.

Unfortunately, however, once an oil spill occurs, we don’t have the luxury of waiting for more research to address lingering scientific and technical concerns. A decision will have to be made quickly and with incomplete information, applied to the situation at the moment. And if, during a large spill, mechanical methods become overwhelmed, the question may be: Is doing nothing else better than using dispersants?

That summer of 2010, in between trips to the Gulf and to hearings in DC, we began to evaluate the observations and science conducted during the spill to build a foundation for planning and decision making in future spills. In 2011, NOAA and our partners held a national workshop of federal, state, industry, and academic scientists to discuss what was known about dispersants and considerations for their use in future spills. You can read the reports and background materials from that workshop.

That was not the only symposium focused on dispersant science and knowledge. Almost every major marine science conference over the past five years has devoted time to the issue. I’ve been involved in workshops and conferences from Florida to Alaska, all wrestling with this issue.

What Have We Learned?

Freshly spilled crude oil in the Ohmsett saltwater test tank starts turning brown after dispersants applied.

The Deepwater Horizon oil spill spawned a larger interest in researching dispersants. Here, you can see freshly spilled crude oil in the Ohmsett saltwater test tank in New Jersey, where the oil starts changing a few minutes after dispersants were applied. Note that some of the oil is still black, but some is turning brown. (NOAA)

Now, five years later, many questions remain and more research is coming out almost daily, including possible impacts from these chemicals on humans—both those active in the response as well as residents near the sites of oiling. Keeping up with this research is a major challenge, but we are working closely with our state and federal partners, including the U.S. Environmental Protection Agency and Coast Guard, as well as those in the academic community to digest the flow of information.

The biggest lesson learned is one we already knew. Once oil is spilled there are no good outcomes and every response technology involves trade-offs.

Dispersants don’t remove oil from the environment, but they do help reduce the concentration of the oil by spreading it out in the water (which ocean currents and other processes do naturally), while also increasing degradation rates of oil. They reduce the amount of floating oil, which reduces the risk for some organisms and environments, but increases the risk for others. We also know that some marine species are even more sensitive to oil than we previously thought, especially for some developmental stages of offshore fish including tuna and mahi mahi.

But we also know, from the Exxon Valdez and other spills, that oil on the shore can persist for decades and create a chronic source of oil exposure for birds, mammals, fish, and shellfish that live near shore. We don’t want oil in the water column, and we don’t want oil in our bays and shorelines. Basically, we don’t want oil spills at all. That sounds like something everyone can agree with.

But until we stop using, storing and transporting oil, we have the risk of spills. The decision to use dispersants or not use dispersants will never be clear cut. Nor will it be done without a lot of discussion of the trade-offs. The many real and heart-felt concerns about potential consequences aren’t dismissed lightly by the responders who have to make tough choices during a spill.

I am reminded of President Harry Truman who reportedly said he wanted a one-handed economist, since his economic advisers would always say, “on the one hand…on the other.”

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