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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Accidents on a Flooded Lower Mississippi River Keep NOAA Busy with a Rash of Spills

Damaged barge on the Mississippi River.

A barge carrying slurry oil being pushed by the towing vessel Amy Francis hit the Natchez-Vidalia Bridge, Jan. 21, 2016. The barge reportedly has a maximum potential of more than 1 million gallons of slurry oil on board. (U.S. Coast Guard)

This is a post by the Office of Response and Restoration’s Donna Roberts.

Did you know that oil spills occur every day in U.S. waters? Rivers bustling with ship traffic, such as the Mississippi, are no exception to this rule.

In the past few weeks, we’ve been involved with quite a few accidents involving vessels carrying oil and chemicals on the Lower Mississippi River.

These river accidents coincided with high water and swift currents. Despite safeguards for vessel traffic put in place by the U.S. Coast Guard, the river conditions resulted in ships colliding, hitting bridges and ground, and breaking away from their towing vessels. One unlucky railroad bridge in Vicksburg, Mississippi, has been hit by vessels five times already this year.

Even now, the NOAA River Forecast Center reports that the Lower Mississippi is experiencing moderate flood conditions. It’s difficult to navigate a river with a tow of barges at any flow—and extremely challenging when the flow is high and fast. In spite of everyone’s best efforts, under conditions like these, accidents can and do still happen, and investigations are ongoing into the precise causes.

Luckily, most of the incidents that have occurred were relatively minor, resulted in no injuries to vessel crews, and all spills received immediate responses from state and federal agencies. Still, when oil or chemicals spill into rivers, we know that they differ from spills in the ocean or along coasts, and therefore present different challenges for spill responders.

Here are just a few of the dozen or so spills and near-spills we know of and which have been keeping our spill modelers, chemists, and Scientific Support Coordinators busy over the past few weeks.

January 21, 2016: A barge being towed by the UTV Amy Frances struck the Natchez Bridge, where Highway 84 crosses over the Lower Mississippi River between Mississippi and Louisiana, in the vicinity of Mile Marker 363. As a result, two of the barge’s tanks were damaged, spilling slurry oil, which our chemical lab confirmed was denser than water. That means this oil sinks.

In the wake of this oil spill, one of our Scientific Support Coordinators helped survey the river to detect sunken oil. Given the river’s very fast and turbulent water at the time, we think any oil released from the damaged tanks was immediately broken into small droplets and carried downstream while also sinking below the river surface. Any oil that reached the bottom was probably mixed with or buried by the sand moving downstream near the river bottom. This is because rivers that move a lot of water also move a lot of sediment.

In addition, we provided information on the expected fate and effects of the barge’s spilled slurry oil and on the animals and habitats that could be at risk.

Workers on a river edge pump oil from a damaged barge.

Response crews remove oil from the damaged MM-46 barge, Jan. 23, 2016, on the Mississippi River. Crews estimate that approximately 76,000 gallons of clarified oil mixture is still unaccounted for. Crews continue to take soundings of the damaged barge tank to determine the amount spilled while assessment teams work to locate missing product. (U.S. Coast Guard)

January 25, 2016: Just a few days later, the Coast Guard called on us for advice related to a barge containing liquid urea ammonium nitrate (liquid fertilizer), which sank south of Valewood, Mississippi, at Mile Marker 501 on the Mississippi River. Side-scan sonar indicates the barge is upside-down on the river bottom, approximately 80 feet down.

Given the position and water pressure, we believe the chemical cargo stored on the barge was likely released into the river. The chemical is heavier than water and will mix quickly into the water column. Because elevated levels of ammonia can affect aquatic life, our focus was on predicting and tracking where the chemical would go downriver and what would happen to it. Salvage efforts for the barge itself continue.

January 26, 2016: The next day, two vessel tows collided upriver of New Orleans, Louisiana, near Mile Marker 130 on the Lower Mississippi River. The collision capsized one of two barges carrying caustic soda, or sodium hydroxide. We provided the Coast Guard with an initial chemical hazard assessment for this chemical, which is a strong base. The release of a large enough quantity of sodium hydroxide could raise the pH of the water around it, posing a risk to local fish and other aquatic life nearby. The barge is secure, but righting it is difficult in the swift currents. No pollution release has been reported to date.

Science for Spills of All Kinds

During these kinds of spills, we have to be ready to provide the same round-the-clock, science-based support to the Coast Guard and other agencies as big spills like the Deepwater Horizon in the Gulf of Mexico.

For example, if a chemical has spilled into a river, we need to know where it’s going to go, what’s going to happen to it, and what, if any, species will be harmed by it. To help answer the “where’s it going?” question, our response specialists use the spill trajectory tool, GNOME, to predict the possible route the pollutant might follow.

To better understand the pollutant and its possible effects, we use software tools such as CAMEO Chemicals to provide information about the chemical’s properties, toxicity, and behavior as it is diluted by the river water. Our Chemical Aquatic Fate and Effects (CAFE) database contains information on the effects of thousands of chemicals, oils, and dispersants on aquatic life.

The Mississippi River and its floodplain are home to a diverse population of living things. On the Lower Mississippi, there may be as many as 60 separate species of mussel. To protect vulnerable species, we use our Environmental Sensitivity Index maps and data to report what animals or habitats could be at risk, particularly those that are threatened or endangered. Keeping responders and the public safe and minimizing environmental harm are two of our top priorities during any spill, no matter the size.

Donna Roberts

Donna Roberts

Donna Roberts is a writer for the Emergency Response Division of NOAA’s Office of Response and Restoration (OR&R). Her work supports the OR&R website and the Environmental Sensitivity Index mapping program.


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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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Science of Oil Spills Training: Apply for Summer 2016

Group of Coast Guard members sit and stand at a table.

These trainings help new and mid-level spill responders increase their understanding of oil spill science when analyzing spills and making risk-based decisions. (NOAA)

NOAA‘s Office of Response and Restoration, a leader in providing scientific information in response to marine pollution, has scheduled a summer Science of Oil Spills (SOS) class in Seattle, Washington, June 6-10, 2016.

Currently, we are accepting applications for three SOS classes for these locations and dates:

  • Mobile, Alabama, the week of March 28, 2016
  • Ann Arbor, Michigan, the week of May 16, 2016
  • Seattle, Washington, the week of June 6, 2016

We will accept applications for these classes as follows:

  • For the Mobile class, the application period will be open until Friday, January 22. We will notify accepted participants by email no later than Friday, February 5.
  • For the Ann Arbor class, the application period will be open until Friday, March 11. We will notify accepted participants by email no later than Friday, March 25.
  • For the Seattle class, the application period will be open until Friday, April 1. We will notify accepted participants by email no later than Friday, April 15.

SOS classes help spill responders increase their understanding of oil spill science when analyzing spills and making risk-based decisions. They are designed for new and mid-level spill responders.

The trainings cover:

  • Fate and behavior of oil spilled in the environment.
  • An introduction to oil chemistry and toxicity.
  • A review of basic spill response options for open water and shorelines.
  • Spill case studies.
  • Principles of ecological risk assessment.
  • A field trip.
  • An introduction to damage assessment techniques.
  • Determining cleanup endpoints.

To view the topics for the next SOS class, download a sample agenda [PDF, 170 KB].

Please understand that classes are not filled on a first-come, first-served basis. We try to diversify the participant composition to ensure a variety of perspectives and experiences, to enrich the workshop for the benefit of all participants. Classes are generally limited to 40 participants.

For more information, and to learn how to apply for the class, visit the SOS Classes page.


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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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Explore Oil Spill Data for Gulf of Mexico Marine Life With NOAA GIS Tools

In the wake of the Deepwater Horizon oil spill, the sheer amount of data scientists were gathering from the Gulf of Mexico was nearly overwhelming. Everything from water quality samples to the locations of oiled sea turtles to photos of dolphins swimming through oil—the list goes on for more than 13 million scientific records.

So, how would anyone even start to dig through all this scientific information? Fortunately, you don’t have to be a NOAA scientist to access, download, or even map it. We have been building tools to allow anyone to access this wealth of information on the Gulf of Mexico environment following the Deepwater Horizon oil spill.

We’re taking a look at two of our geographic information systems tools and how they help scientists, emergency responders, and the public navigate the oceans of environmental data collected since the 2010 Deepwater Horizon oil spill.

When it comes to mapping and understanding huge amounts of these data, we turn to our GIS-based tool, the Environmental Response Management Application, known as ERMA®. This online mapping tool is like a Swiss army knife for organizing data and information for planning and environmental emergencies, such as oil spills and hurricanes.

ERMA not only allows pollution responders to see real-time information, including weather information and ship locations, but also enables users to display years of data, revealing to us broader trends.

View of Environmental Response Management Application showing map of Gulf of Mexico with varying probabilities of oil presence and sea turtle oiling during the Deepwater Horizon oil spill with data source information.

In the “Layer” tab on the right side of the screen, you can choose which groups of data, or “layers,” to display in ERMA. Right click on a data layer, such as “Turtle Captures Probability of Oiling (NOAA) (PDARP),” and select “View metadata” to view more information about the data being shown. (NOAA)

For instance, say you want to know the likelihood of sea turtles being exposed to heavy oil during the Deepwater Horizon oil spill. ERMA enables you to see where sea turtles were spotted during aerial surveys or captured by researchers across the Gulf of Mexico between May and September 2010. At the same time, you can view data showing the probability that certain areas of the ocean surface were oiled (and for how long), all displayed on a single, interactive map.

View of Environmental Management Application map of Gulf of Mexico showing varying probabilities of oil presence and sea turtle exposure to oil during the Deepwater Horizon oil spill with map legend.

Clicking on the “Legend” tab on the right side of the screen shows you basic information about the data displayed in ERMA. Here, the red area represents portions of the Gulf of Mexico which had the highest likelihood of exposing marine life to oil. Triangles show sea turtle sightings and squares show sea turtle captures between May and September 2010. The color of the symbol indicates the likelihood of that sea turtle receiving heavy exposure to oil. (NOAA)

Perhaps you want to focus on where Atlantic bluefin tuna were traveling around the Gulf and where that overlaps with the oil spill’s footprint. Or compare coastal habitat restoration projects with the degree of oil different sections of shoreline experienced. ERMA gives you that access.

You can use ERMA Deepwater Gulf Response to find these data in a number of ways (including search) and choose which GIS “layers” of data to turn on and off in the map. To see the most recently added data, click on the “Recent Data” tab in the upper left of the map interface, or find data by browsing through the “Layers” tab on the right. Or look for data in special “bookmark views” on the lower right of the “Layers” tab to find data for a specific topic of interest.

Now, what if you not only want to see a map of the data, what if you also want to explore any trends in the data at a deeper level? Or download photos, videos, or scientific analyses of the data?

That’s where our data management tool DIVER comes in. This tool serves as a central repository for environmental impact data from the oil spill and was designed to help researchers share and find scientific information ranging from photos and field notes to sample data and analyses.

As Ocean Conservancy’s Elizabeth Fetherston put it:

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.

One of the most important features of DIVER, called DIVER Explorer, is the powerful search function that allows you to narrow down the millions of data pieces to the precise set you’re seeking. You do it one step, or “filter,” at a time.

DIVER software dialog box showing how to build a query by workplan topic area for marine mammals studied during the Deepwater Horizon oil spill.

A view of the step-by-step process of building a “query,” or specialized search, in our DIVER tool for Deepwater Horizon oil spill environmental impact data. (NOAA)

For example, when you go to DIVER Explorer, click on “Guided Query” at the top and then “Start to Explore Data,” choose “By Workplan Topic Area,” hit “Next,” and finally select “Marine Mammals” before clicking “Run Query” to access information about scientific samples taken from marine mammals and turtles. You can view it on a map, in a table, or download the data to analyze yourself.

An even easier way to explore these data in DIVER, however, is by visiting https://www.doi.gov/deepwaterhorizon/adminrecord and scrolling down to and clicking on #5 Preassessment/Assessment (§§ 990.40 – 990.45; 990.51). This will reveal a list of various types of environmental impacts—to birds, sea floor habitat, marine mammals, etc.—which the federal government studied as part of the Deepwater Horizon oil spill’s Natural Resource Damage Assessment.

Say you’re interested in marine mammals, so you click on 5.6 Marine Mammal Injury and then 5.6.3 Data sets. You can then download and open the document “NOAA Marine Mammal data related to the Deepwater Horizon incident, available through systems such as DIVER and ERMA, or as direct downloads. (September 23, 2015).”

Under the section “Data Links,” you can choose from a variety of stored searches (or “queries”) in DIVER that will show you where and when, for example, bottlenose dolphins with satellite tags traveled after the spill (tip: zoom in to view this data on the map)—along with photographs to go with it (tip: click on the “Photos” tab under the map to browse).

Map view of DIVER software map showing where tagged dolphins swam in the Gulf of Mexico after the Deepwater Horizon oil spill.

A map view of DIVER shows where tagged dolphins traveled along the Gulf Coast, showing two populations that stayed in their home bases of Barataria Bay and Mississippi Sound. (NOAA)

This can tell us key information, such as the fact that certain populations of dolphins stay in the same areas along the coast, meaning they don’t travel far from home. We can also look at data about whether those dolphin homes were exposed to a lot of oil, which would suggest that the dolphins that lived there likely were exposed to oil again and again.

Both of these tools allow us to work with incredible amounts of data and see their stories brought to life through the power of geographic information systems. So, go ahead and start exploring!

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