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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Resilience Starts with Being Ready: Better Preparing Our Coasts to Cope with Environmental Disasters

This is a post by Kate Clark, Acting Chief of Staff with NOAA’s Office of Response and Restoration.

If your house were burning down, who would you want to respond? The local firefighters, armed with hoses and broad training in first aid, firefighting, and crowd management? Or would your panicked neighbors running back and forth with five-gallon buckets of water suffice?

Presumably, everyone would choose the trained firefighters. Why?

Well, because they know what they are doing! People who know what they are doing instill confidence and reduce panic—even in the worst situations. By being prepared for an emergency, firefighters and other responders can act quickly and efficiently, reducing injuries to people and damage to property.

People who have considered the range of risks for any given emergency—from a house fire to a hurricane—and have formed plans to deal with those risks are more likely to have access to the right equipment, tools, and information. When disaster strikes, they are ready and able to respond immediately, moving more quickly from response to recovery, each crucial parts of the resilience continuum. If they prepared well, then the impacts to the community may not be as severe, creating an opportunity to bounce back even faster.

Having the right training and plans for dealing with disasters helps individuals, communities, economies, and natural resources better absorb the shock of an emergency. That translates to shorter recovery times and increased resilience.

This shock absorption concept applies to everything from human health to international emergency response to coastal disasters.

For example, the Department of Defense recognizes that building a culture of resilience for soldiers depends on early intervention. For them, that means using early education and training [PDF] to ensure that troops are “mission ready.” Presumably, the more “mission ready” a soldier is before going off to war, the less recovery will be needed, or the smoother that process will be, when a soldier returns from combat.

Similarly, the international humanitarian response community has noted that “resilience itself is not achievable without the capacity to absorb shocks, and it is this capacity that emergency preparedness helps to provide” (Harris, 2013 [PDF]).

NOAA’s Office of Response and Restoration recognizes the importance of training and education for preparing local responders to respond effectively to coastal disasters, from oil spills caused by hurricanes to severe influxes of marine debris due to flooding.

Coastline of Tijuana River National Estuarine Research Reserve in southern California.

Within NOAA, our office is uniquely qualified to provide critical science coordination and advice to the U.S. Coast Guard, FEMA, and other response agencies focused on coastal disaster operations. The result helps optimize the effectiveness of a response and cushion the blow to an affected community, its economy, and its natural resources, helping coasts bounce back to health even more quickly. (NOAA)

In fiscal year 2014 alone, we trained 2,388 emergency responders in oil spill response and planning. With more coastal responders becoming more knowledgeable in how oil and chemicals behave in the environment, more parts of the coast will become better protected against a disaster’s worst effects. In addition to trainings, we are involved in designing and carrying out exercises that simulate an emergency response to a coastal disaster, such as an oil spill, hurricane, or tsunami.

Furthermore, we are always working to collect environmental data in our online environmental response mapping tool, ERMA, and identify sensitive shorelines, habitats, and species before any disaster hits. This doesn’t just help create advance plans for how to respond—including guidance on which areas should receive priority for protection or response—but also helps quickly generate a common picture of the situation and response in the early stages of an environmental disaster response.

After the initial response, NOAA’s Office of Response and Restoration is well-positioned to conduct rapid assessments of impacts to natural resources. These assessments can direct efforts to clean up and restore, for example, an oiled wetland, reducing the long-term impact and expediting recovery for the plants and animals that live there.

Within NOAA, our office is uniquely qualified to provide critical science coordination and advice to the U.S. Coast Guard, FEMA, and other response agencies focused on coastal disaster operations. Our years of experience and scientific expertise enable us to complement their trainings on emergency response operations with time-critical environmental science considerations. The result helps optimize the effectiveness of a response and cushion the blow to an affected community, its economy, and its natural resources. Our popular Science of Oil Spills class, held several times a year around the nation, is just one such example.

Additionally, we are working with coastal states to develop response plans for marine debris following disasters, to educate the public on how we evaluate the environmental impacts of and determine restoration needs after oil and chemical spills, and to develop publicly available tools that aggregate and display essential information needed to make critical response decisions during environmental disasters.

You can learn more about our efforts to improve resilience through readiness at response.restoration.noaa.gov.

Kate Clark.Kate Clark is the Acting Chief of Staff for NOAA’s Office of Response and Restoration. For nearly 12 years she has responded to and conducted damage assessment for numerous environmental pollution events for NOAA’s Office of Response and Restoration. She has also managed NOAA’s Arctic policy portfolio and served as a senior analyst to the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.


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Science of Oil Spills Training Now Accepting Applications for December 2015

Several response personnel at the harbor's edge.

NOAA spill specialists were among those responding when 233,000 gallons (1,400 tons) of molasses were spilled into Hawaii’s Honolulu Harbor in 2013. (U.S. Coast Guard)

NOAA‘s Office of Response and Restoration, a leader in providing scientific information in response to marine pollution, has scheduled a Science of Oil Spills (SOS) class for the week of December 7, 2015 in Honolulu, Hawaii.

We will accept applications for this class until Friday, October 16, and we will notify applicants regarding their participation status by Friday, October 30, via email.

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.

These 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 be advised 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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To Bring Back Healthy California Ocean Ecosystems, NOAA and Partners Are “Planting” Long-Lost Abalone in the Sea

This is a post by Gabrielle Dorr, NOAA/Montrose Settlements Restoration Program Outreach Coordinator.

Diver placing PVC tube with small sea snails on the rocky seafloor.

A diver places a PVC tube filled with young green abalone — sea snails raised in a lab — on the seafloor off the southern California coast. (NOAA)

They weren’t vegetables but an excited group of scuba divers was carefully “planting” green abalone in an undersea garden off the southern California coast all the same. Green abalone are a single-shelled species of sea snail whose population has dropped dramatically in recent decades.

On a Wednesday in mid-June, these oceanic “gardeners”—NOAA biologists along with key partners including The Nature Conservancy, The Bay Foundation, and The SEA Lab—released over 700 young green abalone into newly restored kelp forest areas near Palos Verdes, California. This was the first time in over a decade that juvenile abalone have been “outplanted,” or transplanted from nursery facilities, to the wild in southern California.

Spawned and reared at The SEA Lab in Redondo Beach, California, all of the juvenile abalone were between two and four years old and were between a quarter inch and 3 inches in size. Biologists painstakingly tagged each abalone with tiny identifying tags several weeks prior to their release into the wild.

Leading up to outplanting day, microbiologists from the California Department of Fish and Wildlife had to run rigorous tests on a sample of the juvenile abalone to certify them as disease-free before they were placed into the ocean. Several days before transferring them, biologists placed the abalone in PVC tubes with netting on either end for easy transport.

“This was just a pilot outplanting with many more larger-scale efforts to come in the near future,” stated David Witting from NOAA’s Restoration Center. “We wanted to go through all of the steps necessary to successfully outplant abalone so that it would be second nature next time.”

Witting and a team of divers will be going out over the next six to twelve months to monitor the abalone—checking for survival rates and movement of the abalone. “We expect to find some abalone that didn’t survive the transfer to the wild but probably a good number of them will move into the cracks and crevices of rocky reef outcroppings immediately.”

Why Abalone?

PVC tube filled with green abalone lodged into the rocky seafloor.

After testing and refining the techniques to boost the population of green abalone in the wild, scientists then will apply them to help endangered white and black abalone species recover. (NOAA)

All seven abalone species found along the U.S. West Coast have declined and some have all but disappeared. White and black abalone, in particular, are listed as endangered through the Endangered Species Act (ESA). Three abalone species (green, pinto, and pink) are listed as Species of Concern by NOAA Fisheries, a designation meant to protect the populations from declining further and which could result in an ESA listing. The two remaining abalone species, reds and flats, are protected and managed by states along the U.S. West Coast.

Historically, the main cause of abalone’s demise was a combination of overfishing and disease. Today, many other threats, such as poaching, climate change, oil spills, and habitat degradation, contribute to the decline of abalone and could impact the health of future populations.

The recent green abalone outplanting was one of the many steps needed to advance the recovery of all abalone species. Methods for rearing and outplanting are first being tested using green abalone because this species is more abundant in the wild. Once the methods are refined, they then will be employed to recover endangered white and black abalone—both species which are currently living on the brink of extinction.

What the Future Holds

A small green abalone eats red algae stuck to a plastic rack.

A young green abalone, reared in a lab in southern California, grazes on red algae. Raising these sea snails in a lab requires a lot of resources, prompting scientists to explore other approaches for boosting wild abalone populations. (Credit: Brenda Rees, with permission)

In particular, biologists are hoping to refine a technique they are coining “deck-spawning” as a way to outplant abalone in the future. Maintaining abalone broodstock and rearing them in a lab requires a lot of resources, funding, and time. This monumental effort has spurred biologists to develop an initially successful, alternate approach, which involves inducing mature, wild abalone to spawn on the deck of a boat.

The scientists then take the viable abalone larvae that develop and release them in a habitat where the young abalone are likely to settle and thrive. Immediately after spawning, the parent abalone can then be returned to the wild where they can continue to be a component of the functioning ocean ecosystem.

The green abalone outplanting project is part of a broader effort to restore abalone but is also playing an important role in work being done by NOAA’s Montrose Settlements Restoration Program to restore southern California’s kelp forests. In southern California, fish habitat has been harmed by decades of toxic pollution dumped into the marine environment. After clearing areas that would be prime kelp habitat if not for the unnaturally high densities of sick and stressed sea urchins, NOAA and our partners have seen kelp bounce back once given relief from those overly hungry urchins.

While abalone also eat seaweed, including kelp, they are a natural competitor of urchins in this environment and will help keep urchin populations in check, ultimately allowing a healthy kelp forest community to return.

Watch as divers transport the young abalone using PVC tubes and release them on the rocky seafloor off California’s coast:

View of video player showing abalone in plastic tube on seafloor.

Gabrielle Dorr

Gabrielle Dorr.

Gabrielle Dorr is the Outreach Coordinator for the Montrose Settlements Restoration Program as part of NOAA’s Restoration Center. She lives and works in Long Beach, California, where she is always interacting with the local community through outreach events, public meetings, and fishing education programs.


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How to Keep Your Belongings From Becoming Trashed by Hurricanes

Destroyed dock and debris along a populated canal in Louisiana.

No matter the size of the storm, you and your family can take steps to reduce the likelihood of your stuff becoming storm debris. (U.S. Coast Guard)

Winds, heavy rains, flooding, storm surge. Hurricanes and other powerful storms can cause a lot of damage, both to people’s lives, of course, but also to the surrounding land and waters.

Docks, storage tanks, and buildings can be ripped off their foundations. Oil drums, shipping containers, and lumber can get swept away in floodwaters. A boat could end up in someone’s living room.

Much of this destruction introduces debris into coastal waterways and wetlands. This is one of several ways NOAA’s Office of Response and Restoration, through the NOAA Marine Debris Program, becomes involved after hurricanes.

While we can’t prevent hurricanes, we can prepare for them. That means doing everything you can to keep you, your family, and your belongings safe, far ahead of any natural disaster.

No matter the size of the storm, you and your family can take steps to reduce the likelihood of your stuff becoming storm debris. It is difficult to prevent buildings or large boats from becoming debris, especially during a large storm, but smaller items be safely stored or secured. After all, no one wants their patio umbrella to knock out a neighbor’s window before it ends up swimming with the fishes.

Here are a few ways to help protect yourself and your belongings in case of a hurricane:

  • Create a plan for your family and home [PDF], practice your evacuation route, and stock an emergency supply kit.
  • Secure yard items before a storm. Make a list of items to bring inside in case of hurricane-force winds or flooding. This could be patio furniture, lawn decorations, tools, trash cans, planters, etc.
  • Invest in storm-resilient building designs, which might include raising the level of your house for areas at high risk of flooding or installing a roof that can withstand high winds.
  • Boaters and fishers: Pull vessels and fishing gear out of the water before a storm. If you’re unable to remove the boat from the water, properly secure it [PDF].

A Boat out of Water

Boat half-sunk in Vermilion Bay, Lousiana.

Finding a safe and secure location for boats during a storm proves to be a huge challenge for many along the coasts, which is how a great deal of boats end up like this one after Hurricanes Katrina and Rita. (U.S. Coast. Guard)

Dealing with the large number of abandoned and derelict vessels after a storm is often a complicated and expensive ordeal. As a result, we should try to keep boats from ending up in this sorry state in the first place. Unfortunately, finding a safe and secure location for boats during a storm proves to be a huge challenge for many along the coasts.

A few areas do show promise in creating safe spaces for vessels during storms. One example is the Clean and Resilient Marina Initiative from the Gulf of Mexico Alliance, a regional partnership made up of the Gulf states. According to the alliance, “This improved program…provides additional recommendations to strengthen local marinas’ ability to withstand natural and man-made disasters.”

The initiative offers best management practices [PDF] for incorporating resilience and environmental responsibility into everything from the design and siting of marinas to strategies for evacuating them during a disaster.

Another example is the concept of “harbors of refuge,” which several organizations in Louisiana are looking to implement on public lands along the coast. A harbor of safe refuge is “a port, inlet, or other body of water normally sheltered from heavy seas by land and in which a vessel can navigate and safely moor.”

Providing resilient infrastructure able to withstand high winds and waters helps better protect boats, and offering these facilities on public lands creates opportunities for public funding to help pay for the upgrades or for salvage after a storm.

Taking on Disasters

The NOAA Marine Debris Program (MDP) is also taking a proactive approach to planning for disasters.

Cover of Alabama Incident Waterway Debris Response Plan, with damaged boats.

The NOAA Marine Debris Program worked with the State of Alabama to release the first in a series of comprehensive plans to help coastal states better prepare for an acute waterway debris release, such as in a hurricane. (NOAA)

In 2012, Congress expanded the program’s responsibilities to include “severe marine debris events,” which formalized their role in preparing for and responding to disaster debris.

This was in the wake of the 2011 Japan earthquake and tsunami, and states were struggling to deal with the tsunami debris—from small boats to massive docks—washing up on U.S. shores. Furthermore, the massive storm known as Sandy had recently hit the East Coast, leaving its own path of destruction along coastal waterways.

As a result, the NOAA MDP has started a proactive planning program for dealing with these types of large, disaster-related debris events. They began by working with the State of Alabama to develop a waterway debris emergency response plan and will now move on to work with other coastal states.

This effort includes both a comprehensive plan and field action guide which spells out information such as which agencies have authorities to remove disaster-related debris if it lands in a given waterway, as well as points of contact at those agencies. The plan is meant to be a broad, useful tool both for the NOAA MDP and the state in case of a natural disaster producing large amounts of debris.

To learn more about how you can prepare for hurricanes, visit NOAA’s National Hurricane Center at www.nhc.noaa.gov/prepare/, and read more about the NOAA Marine Debris Program’s efforts at marinedebris.noaa.gov/current-efforts/emergency-response.


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This Is How We Help Make the Ocean a Better Place for Coral

Large corals on the seafloor.

The ocean on its own is an amazing place. Which is why we humans like to explore it, from its warm, sandy beaches to its dark, mysterious depths. But when humans are involved, things can and often do go wrong.

That’s where we come in. Our corner of NOAA helps figure out what impacts have happened and what restoration is needed to make up for them when humans create a mess of the ocean, from oil spills to ship groundings.

In honor of World Ocean Day, here are a few ways we at NOAA make the ocean a better place for corals when ships accidentally turn them into undersea roadkill.

First, we literally vacuum up broken coral and rubble from the seafloor after ships run into and get stuck on coral reefs. The ships end up crushing corals’ calcium carbonate homes, often carpeting the seafloor with rubble that needs to be removed for three reasons.

  1. To prevent it from smashing into healthy coral nearby.
  2. To clear space for re-attaching coral during restoration.
  3. To allow for tiny, free-floating coral babies to settle in the cleared area and start growing.

Check it out:A SCUBA diver using a suction tube to vacuum coral rubble from the seafloor during coral restoration after the VogeTrader ship grounding.Sometimes, however, the broken bits get stuck in the suction tube, and you have to give it a good shake to get things moving. SCUBA divers shaking a suction tube to clear it on the seafloor.Next, we save as many dislodged and knocked over corals as we can. In this case, popping them into a giant underwater basket that a boat pulls to the final restoration site.

SCUBA diver placing coral piece into a large wire basket on the seafloor during coral restoration after the VogeTrader ship grounding.Sometimes we use “coral nurseries” to regrow corals to replace the ones that were damaged. This is what that can look like:

Staghorn coral fragments hanging on an underwater tree structure of PVC pipes.Then, we cement healthy corals to the seafloor, but first we have to prepare the area, which includes scrubbing a spot for the cement and coral to stick to.

SCUBA diver scrubbing a spot on the seafloor for the cement and coral to stick to.(And if that doesn’t work very well, we’ll bring out a power washer to get the job done.)

SCUBA diver using a power washer to clear a spot on the seafloor for the cement and coral to stick to during coral restoration after the VogeTrader ship grounding.Finally, we’re ready for the bucket of cement and the healthy coral.

SCUBA diver turning over a bucket of cement on the seafloor during coral restoration after the VogeTrader ship grounding.

Instead of cement, we may also use epoxy, nails, or cable ties to secure corals to the ocean floor.

After all that work, the seafloor goes from looking like this:

View of seafloor devoid of coral before restoration.To this:

View of seafloor covered with healthy young coral and fish after restoration due to the VogeTrader grounding.

Ta-da! Good as new, or at least, on its way back to being good-as-new.

When that’s not enough to make up for all the harm done to coral reefs hit by ships, we look for other restoration projects to help corals in the area, like this project to vacuum invasive algae off of coral reefs in Oahu.

Watch how this device, dubbed the “Super Sucker,” works to efficiently remove the yellow-brown algae that is smothering the corals:

Or, as another example of a coral restoration project, we set sail each year to the remote Papahānaumokuākea Marine National Monument in the Northwestern Hawaiian Islands to pull more than 50 tons of giant, abandoned fishing nets off of the pristine coral reefs.

In 2014, that included removing an 11 ton “monster net” from a reef:

For the most part, the coral restoration you’ve seen here was completed by NOAA and our partners, beginning in October 2013 and wrapping up in April 2014.

These corals were damaged off the Hawaiian island of Oahu in February of 2010 when the cargo ship M/V VogeTrader ran aground and was later removed from a coral reef in Kalaeloa/Barber’s Point Harbor.


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On the Front Lines of an Oil Spill in My Own Backyard: A Report from Santa Barbara, California

This is a post by Gabrielle Dorr, NOAA/Montrose Settlements Restoration Program Outreach Coordinator.

Oiled boulders on a California beach with cleanup workers in the distance.

NOAA has been involved with the May 19, 2015 oil spill resulting from a pipeline break at Refugio State Beach, near Santa Barbara, California, which released an estimated 100,000 gallons of crude oil, with a reported 21,000 gallons reaching the ocean. (Bill Stanley/U.S. Fish and Wildlife Service)

When I first heard about the pipeline oil spill at Refugio State Beach near Santa Barbara, California, a couple weeks ago, I felt concerned about the fact that it was only a few hours up the coast from where I currently live and work. I couldn’t stop thinking about what the long-term impacts would be to the beautiful beaches we have here in southern California.

As a NOAA communications specialist who had cut her teeth in providing communications support for the 2010 Deepwater Horizon oil spill, I thought I knew roughly what to expect when I was called in to help in Santa Barbara.

When I was asked to provide support for that oil spill in July 2010, oil had been gushing into the ocean for several months and was washing up on beaches bordering five states far from my home in California. I was able to get out into the field in Louisiana to see firsthand what an oiled marsh looks like, but that was months after the spill began. In addition, the massive scale of the response and damage assessment efforts made it tough to grasp the full picture of the spill.

Still, it was important for me to see the impacts for myself, so that I could better tell the story about what happened and what NOAA and our partners were going to do to make it right.

From the Gulf of Mexico to Southern California

Fish being measured on a table.

After an oil spill, scientists collect lots of data on the potential impacts of the oil and response efforts to fish, birds, and wildlife. (NOAA)

This time, at Refugio State Beach, was different. I was stationed at a command center for those working to assess the environmental impacts of the spill only three days after a pipeline released up to 105,000 gallons of oil, with at least 21,000 gallons reaching the Pacific Ocean north of Santa Barbara.

From the start of this oil spill, I was able to see the inner workings of the Natural Resource Damage Assessment process and how complex and challenging this process can be for the scientists involved. Biologists, armed with notebooks and cameras, were diligently filling out paperwork and going over every painstaking detail of their data. Collecting good data is extremely important at this early stage because it will be used as evidence showing the oil spill’s potential impacts to wildlife and natural areas.

The next day I was asked to follow a team into the field to take photos of them collecting fish samples from one of the oil spill’s “hot zones.” At the stretch of Refugio State Beach where the majority of the oil cleanup activities were taking place, it was easy to be overwhelmed by the scene. There were a huge number of trucks, cars, buses, people in hard hats, reporters, and even an eating area with eight large tables set up under tents.

That day I was part of a team of nine people who would be sampling fish for oil contamination, with representatives from NOAA, the National Park Service, California Department of Fish and Wildlife, and an environmental consulting firm representing Plains All American Pipeline, the company responsible for the leaking pipeline. When we checked in with the on-site safety officer, he told us that we would need to wear Tyvek suits, booties taped around our calves, gloves, and hard hats.

Oil and Fish Don’t Mix

Out on the beach it was hard not to step in oil since it covered most of the cobble rocks lining the beach in a thick band. I watched as the team baited their hooks and cast their lines in the water. The fishing team spread out along the beach, making the job of running buckets of samples between those catching and processing the fish even more challenging.

Once I had finished taking photos, I began shuttling buckets of fish from the edge of the contaminated zone to a picnic table several yards away. There, two women were working hard to process the samples of fish that will later be analyzed for oil contaminants in a lab.

The team caught 18 barred surfperch in total, giving us a robust sample of the local population which might have been affected by the oil spill. It was a successful day of sampling, but at the same time, I found it difficult not to think about how all of that oil was going to be cleaned off of those rocks.

Working at the front line of the oil spill at Refugio State Beach was a unique experience for me, but it also feels a little too close to home. When I was responding to the Deepwater Horizon oil spill in the Gulf of Mexico, I was stationed two hours away from the nearest coast and lived almost 2,000 miles away in California.

I found having an oil spill in your own backyard is much more personal and reminds me of how important it is to plan, train, and prepare for oil spills long before any oil hits the water.

For more information on the response to this oil spill, visit the Refugio Response Joint Information Center website.

Gabrielle Dorr

Gabrielle Dorr.

Gabrielle Dorr is the Outreach Coordinator for the Montrose Settlements Restoration Program as part of NOAA’s Restoration Center. She lives and works in Long Beach, California, where she is always interacting with the local community through outreach events, public meetings, and fishing education programs.


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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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