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An inside look at the science of cleaning up and fixing the mess of marine pollution

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In Florida, Rallying Citizen Scientists to Place an Ocean-Sized Problem Under the Microscope

This week, we’re exploring the problem of plastics in our ocean and the solutions that are making a difference. To learn more about #OceanPlastics this week, keep your eye on Facebook, Twitter, Instagram, NOAA’s Marine Debris Blog, and, of course, here.

Young woman filling a one liter bottle with water along a marshy beach.

Florida Sea Grant has been teaching volunteers how to sample and examine Florida’s coastal waters for microplastics and educating the public on reducing their contribution to microplastic pollution. (Credit: Tyler Jones, University of Florida, Institute of Food and Agricultural Sciences)

Have you ever looked under a microscope at what’s in a sample of ocean water? What do you think you would find?

These days, chances are you would spot tiny bits of plastic known as microplastics, which are less than 5 millimeters long (about the size of a sesame seed).

The Florida Microplastic Awareness Project is giving people the opportunity to glimpse into Florida’s waters and see a microscopic world of plastic pollution up close. This project integrates citizen science—when volunteers contribute to scientific research—with education about microplastics.

I recently spoke with Dr. Maia McGuire of Florida Sea Grant. She’s leading the Florida Microplastic Awareness Project, which is funded by a grant from the NOAA Marine Debris Program. NOAA’s Office of Response and Restoration, of which the Marine Debris Program is a part, has a long history of collaborating with Sea Grant programs across the nation on a range of issues, including marine debris.

The NOAA Marine Debris Program has funded more than a dozen marine debris removal and prevention projects involving Sea Grant, and has participated in other collaborations with regional Sea Grant offices on planning, outreach, education, and training efforts. Many of these efforts, including the Florida Microplastic Awareness Project, center on preventing marine debris by increasing people’s awareness of what contributes to this problem.

Combining Science with Action

Blue and white plastic fibers viewed under a microscope.

Volunteers record an average of eight pieces of microplastic per liter of water, with seven of those eight identified as plastic fibers (viewed here under a microscope). (Credit: Maia McGuire, University of Florida, Institute of Food and Agricultural Sciences)

This latest effort, the Florida Microplastic Awareness Project, involves building a network of volunteers and training them to collect one liter water samples from around coastal Florida, to examine those samples under the microscope, and then to assess and record how many and what kinds of microplastics they find.

“Everything is microscopic-sized,” explains McGuire. “We’re educating people about sources of these plastics. A lot of it is single-use plastic items, like bags, coffee cups, and drinking straws. But we’re finding a large number are fibers, which come from laundering synthetic clothes or from ropes and tarps.”

Volunteers (and everyone else McGuire’s team talks to) also choose from a list of eight actions to reduce their contribution to plastic pollution and make pledges that range from saying no to plastic drinking straws to bringing washable to-go containers to restaurants for leftovers. For those who opt-in, the project coordinators follow up every three months to find out which actions the pledgers have actually taken.

“It’s been encouraging,” McGuire says, “because with the pledge and follow up, what we’ve found is that they pledge to take 3.5 actions on average and actually take 3.5 actions when you follow up.”

She adds a caveat, “It’s all self-reported, so take that for what it’s worth. But people are coming up to me and saying, ‘I checked my face scrub and it had those microbeads.’ It’s definitely resonating with people.”

Microplastics Under the Microscope

The project has trained 16 regional coordinators, who are based all around coastal Florida. They in turn train the volunteer citizen scientists, who, as of June 1, 2016, have collected 459 water samples from 185 different locations, such as boat ramps, private docks, and county parks along the coast.

“Some folks are going out monthly to the same spot to sample,” McGuire says, “some are going out to one place once, and others are going out occasionally.”

After volunteers collect their one liter sample of water, they bring it into the nearest partner facility with filtration equipment, which are often offices or university laboratories close to the beach. In each lab, volunteers then filter the water sample, using a vacuum filter pump, through a funnel lined with filter paper. “The filter paper has grid lines printed on it so you’re not double counting or missing any pieces,” McGuire adds.

Once the entire sample has been filtered, volunteers place the filter paper with the sample’s contents into a petri dish under a microscope at 40 times magnification. “Because we’re collecting one liter water samples, everything we’re getting is teeny-tiny,” McGuire says. “Nothing really is visible with the naked eye.”

Letting the filter paper dry often makes identifying microplastics easier because microscopic plastic fibers spring up when dry. And they are finding a lot of plastic fibers. On average, volunteers record eight pieces of microplastic per liter of water, and of those, seven are fibers. They are discovering at least one piece of plastic in nearly all of the water samples.

“If they have questions about if something is plastic, we have a sewing needle they heat in a flame,” McGuire says, “and put it under the microscope next to the fiber, and if it’s plastic, it changes shape in response to the heat.”

Next, volunteers record their data, categorizing everything into four different types of plastic: plastic wrap and bags, fibers, beads, or fragments. They use online forms to send in their data and log their volunteer information. McGuire is the recipient of all that data, which she sorts and then uploads to an online map, where anyone can view the project’s progress.

A Learning Process

Tiny white and purple beads piled next to a dime.

These purple and white microbeads are what microplastics extracted from facial scrub looks like next to a dime. Microbeads are being phased out of personal care products thanks to federal law. (Credit: Dave Graff)

“When I first wrote the grant proposal—a year and a half ago or more—I was expecting to find a lot more of the microbeads, because we were starting to hear more in the news about toothpaste and facial scrubs and the quantity of microbeads,” McGuire relates. “It was a little surprising at first to find so many [plastic] fibers. We have some sites near effluent outfalls from water treatment plants.”

However, McGuire points out that what they’re finding is comparable to what other researchers are turning up in the ocean and Great Lakes, except for one important point. Many of those researchers take water samples using nets with a 0.3 millimeter mesh size. By filtering through paper rather than a net, McGuire’s volunteers are able to detect much smaller microplastics, like the fibers, which otherwise would pass through a net.

“I think one big take-home message is there’s still so much we don’t know,” McGuire says. “We don’t have a lot of knowledge or research about what the impacts [of microplastics] actually are. We need a lot more research on this topic.”

Learn more about what you can do to reduce your contribution to plastic pollution, take the pledge with the Florida Microplastic Awareness Project, and dive into the research projects supported by the NOAA Marine Debris Program, which are exploring:

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For the First Time in Decades, Scientists Examine How Oil Spills Might Affect Baleen Whales

A North Atlantic right whale's mouth is visible at the ocean surface.

NOAA scientists and partners recently collaborated to examine how oil and dispersants might affect the function of baleen in humpback, bowhead, and right whales (pictured). Hundreds of baleen plates hang from these whales’ top jaws and allow them to filter food from the water. (Credit: Georgia Department of Natural Resources, Permit 15488)

Several days of unseasonably warm weather in late September had Gary Shigenaka starting to wonder how much longer he and his colleagues would be welcome at Ohmsett, a national oil spill research facility in New Jersey.

They were working with whale baleen, and although the gum tissue anchoring their baleen samples had been preserved with formalin, the balmy fall weather was taking a toll. As a result, things were starting to smell a little rank.

Fortunately, cooler weather rounded out that first week of experiments, and the group, of course, was invited back again. Over the course of three week-long trials in September, December, and January, they were trying to tease out the potential impacts of oil and dispersants on whale baleen.

As a marine biologist with NOAA’s Office of Response and Restoration, Shigenaka’s job is to consider how oil spills might threaten marine life and advise the U.S. Coast Guard on this issue during a spill response.

But the last time scientists had examined how oil might affect whale baleen was in a handful of studies back in the 1980s. This research took place before the 1989 Exxon Valdez and 2010 Deepwater Horizon oil spills and predated numerous advances in scientific technique, technology, and understanding.

Thanks to a recent opportunity provided by the U.S. Bureau of Safety and Environmental Enforcement, which runs the Ohmsett facility, Shigenaka and a team of scientists, engineers, and oil spill experts have been able to revisit this question in the facility’s 2.6 million gallon saltwater tank.

The diverse team that made this study possible hails not just from NOAA but also Alaska’s North Slope Borough Department of Wildlife Management (Dr. Todd Sformo), Woods Hole Oceanographic Institution (Dr. Michael Moore and Tom Lanagan), Hampden-Sydney College (Dr. Alexander Werth), and Oil Spill Response Limited (Paul Schuler). In addition, NOAA’s Marine Mammal Health and Stranding Response Program provided substantial support for the project, including funding and regulatory expertise, and was coordinated by Dr. Teri Rowles.

Getting a Mouthful

To understand why this group is focused on baleen and how an oil spill might affect this particular part of a whale, you first need to understand what baleen is and how a whale uses it. Similar to fingernails and hooves, baleen is composed of the protein keratin, along with a few calcium salts, giving it a tough but pliable character.

A hand holds a ruler next to oiled baleen hanging from a clamp next to a man.

Made of the flexible substance keratin, baleen plates have tangles of “fringe hair” that act as nets to strain marine life from mouthfuls of ocean water. This study examined how oil and dispersants might affect the performance of baleen. (NOAA)

Twelve species of whales, including humpback and bowhead, have hundreds of long plates of baleen hanging from the top jaw, lined up like the teeth on a comb, which they use to filter feed. A whale’s tongue rubs against its baleen plates, fraying their inner edges and creating tangles of “fringe hair” that act like nets to catch tiny sea creatures as the whale strains massive gulps of ocean water back out through the baleen plates.

Baleen does vary somewhat between species of whales. Some might have longer or shorter baleen plates, for example, depending on what the whale eats. Bowhead whales, which are Arctic plankton-eaters, can have plates up to 13 feet long.

This study was, at least in part, inspired by scientists wondering what would happen to a bowhead whale if a mouthful of water brought not just lunch but also crude oil from an ill-fated tanker traversing its Arctic waters.

Would oil pass through a whale’s hundreds of baleen plates and coat their mats of fringe hairs? Would that oil make it more difficult for the whale to push huge volumes of water through the oily baleen, causing the whale to use more energy as it tried? Does that result change whether the oil is freshly spilled, or weathered with age, or dispersed with chemicals? Would dispersant make it easier for oil to reach a whale’s gut?

Using more energy to get food would mean the whales then would need to eat even more food to make up for the energy difference, creating a tiring cycle that could tax these gargantuan marine mammals.

Testing this hypothesis has been the objective of Shigenaka’s team. While it might sound simple, almost nothing about the project has been straightforward.

Challenges as Big as a Whale

One of the first challenges was tackled by the engineers at Woods Hole Oceanographic Institution. They were tasked with turning the mechanical features of Ohmsett’s giant saltwater tank into, essentially, a baleen whale’s mouth.

Woods Hole fabricated a special clamp and then worked with the Ohmsett engineering staff to attach it to a corresponding mount on the mechanical bridges that move back and forth over the giant tank. The clamp gripped the sections of baleen and allowed them to be held at different angles as they moved through the water. In addition, this custom clamp had a load cell, which was connected to a computer on the bridge. As the bridge moved the clamp and baleen at different speeds and angles through the water, the team could measure change in drag on the baleen via the load cell.

With the mechanical portion set up, the Ohmsett staff released oil into the test tank on the surface of the water, and the team watched expectantly how the bridges moved the baleen through the thin oil slick. It turned out to be a pretty inefficient way to get oil on baleen. “How might a whale deal with oil on the surface of the water?” asked Shigenaka. “If it’s feeding, it might scoop up a mouthful of water and oil and run it through the baleen.” But how could they simulate that experience?

They tried using paintbrushes to apply crude oil to the baleen, but that seemed to alter the character of the baleen too much, matting down the fringe hairs. After discussions with the Ohmsett engineering staff, the research team finally settled on dipping the baleen into a pool of floating oil that was contained by a floating ring. This set-up allowed a relatively heavy amount of oil to contact baleen in the water and would help the scientists calibrate their expectations about potential impacts.

Testing the Waters

Four black plumes of dispersed oil are released underwater onto long plates of baleen moving behind the applicator.

After mixing chemical dispersant with oil, the research team released plumes of it underwater in Ohmsett’s test tank as baleen samples moved through the water behind the applicator. Researchers also tested the effects of dispersant alone on baleen function. (NOAA)

In all, Shigenaka and his teammates ran 127 different trials across this experiment. They measured the drag values for baleen in a variety of combinations: through saltwater alone, with fresh oil, with weathered oil, with dispersed oil (pre-mixed and released underwater through a custom array designed and built by Ohmsett staff), and with chemical dispersant alone. They tested during temperate weather as well as lower temperature conditions, which clearly thickened the consistency of the oil. They conducted the tests using baleen from three different species of whales: bowhead, humpback, and right whale.

Following all the required regulations and with the proper permits, the bowhead baleen was donated by subsistence whalers from Barrow, Alaska. The baleen from other species came from whales that had stranded on beaches from locations outside of Alaska.

In addition to testing the potential changes in drag on the baleen, the team of researchers used an electric razor to shave off baleen fringe hairs as samples for chemical analysis to determine whether the oil or dispersant had any effects on baleen at the molecular level. They also determined how much oil, dispersed oil, and dispersant were retained on the baleen fringe hairs after the trials.

At this point, the team is analyzing the data from the experimental trials and plans to submit the results for publication in a scientific journal. NOAA is also beginning to create a guidance document on oil and cetaceans (whales and dolphins), which will incorporate the conclusions of this research.

While the scientific community has learned a lot about the apparent effects of oil on dolphins in the wake of the 2010 Deepwater Horizon oil spill, there is very little information on large whales. The body of research on oil’s effects on baleen from the 1980s concluded that there were few and transient effects, but whether that conclusion holds up today remains to be seen.

“This is another piece of the puzzle,” said Shigenaka. “If we can distill response-relevant guidance that helps to mediate spill impacts to whales, then we will have been successful.”

Work was conducted under NOAA’s National Marine Fisheries Service Permits 17350 and 18786.


NOAA Scientist Helps Make Mapping Vital Seagrass Habitat Easier and More Accurate

Shoal grass seagrass on a sandy ocean floor.

Seagrass beds serve as important habitat for a variety of marine life, and understanding their growth patterns better can help fisheries management and restoration efforts. (NOAA)

Amy Uhrin was sensing a challenge ahead of her. As a NOAA scientist working on her PhD, she was studying the way seagrasses grow in different patterns along the coast, and she knew that these underwater plants don’t always create lush, unbroken lawns beneath the water’s surface.

Where she was working, off the North Carolina coast near the Outer Banks, things like the churning motion of waves and the speed of tides can cause seagrass beds to grow in patchy formations. Clusters of bigger patches of seagrass here, some clusters of smaller patches over there. Round patches here, elongated patches over there.

Uhrin wanted to be able to look at aerial images showing large swaths of seagrass habitat and measure how much was actually seagrass, rather than bare sand on the bottom of the estuary. Unfortunately, traditional methods for doing this were tedious and tended to produce rather rough estimates. These involved viewing high-resolution aerial photographs, taken from fixed-wing planes, on a computer monitor and having a person digitally draw lines around the approximate edges of seagrass beds.

While that can be fairly accurate for continuous seagrass beds, it becomes more problematic for areas with lots of small patches of seagrass included inside a single boundary. For the patchy seagrass beds Uhrin was interested in, these visual methods tended to overestimate the actual area of seagrass by 70% to more than 1,500%. There had to be a better way.

Seeing the Light

Patches of seagrass beds of different sizes visible from the air.

Due to local environmental conditions, some coastal areas are more likely to produce patchy patterns in seagrass, rather than large beds with continuous cover. (NOAA)

At the time, Uhrin was taking a class on remote sensing technology, which uses airborne—or, in the case of satellites, space-borne—sensors to gather information about the Earth’s surface (including information about oil spills). She knew that the imagery gathered from satellites (i.e. Landsat) is usually not at a fine enough resolution to view the details of the seagrass beds she was studying. Each pixel on Landsat images is 30 meters by 30 meters, while the aerial photography gathered from low-flying planes often delivered resolution of less than a meter (a little over three feet).

Uhrin wondered if she could apply to the aerial photographs some of the semi-automated classification tools from imagery visualization and analysis programs which are typically used with satellite imagery. She decided to give it a try.

First, she obtained aerial photographs taken of six sites in the shallow coastal waters of North Carolina’s Albemarle-Pamlico Estuary System. Using a GIS program, she drew boundaries (called “polygons”) around groups of seagrass patches to the best of her ability but in the usual fashion, which includes a lot of unvegetated seabed interspersed among seagrass patches.

Six aerial photographs of seagrass habitat off the North Carolina coast, with yellow boundary lines drawn around general areas of seagrass habitat.

Aerial photographs show varying patterns of seagrass growth at six study sites off the North Carolina coast. The yellow line shows the digitally drawn boundaries around seagrass and how much of that area is unvegetated for patchy seagrass habitat. (North Carolina Department of Transportation)

Next, Uhrin isolated those polygons of seagrass beds and deleted everything else in each image except the polygon. This created a smaller, easier-to-scan area for the imagery visualization program to analyze. Then, she “trained” the program to recognize what was seagrass vs. sand, based on spectral information available in the aerial photographs.

Though limited compared to what is available from satellite sensors, aerial photographs contain red, blue, and green wavelengths of light in the visible spectrum. Because plants absorb red and blue light and reflect green light (giving them their characteristic green appearance), Uhrin could train the computer program to classify as seagrass the patches where green light was reflected.

Classify in the Sky

Amy Uhrin stands in shallow water documenting data about seagrass inside a square frame of PVC pipe.

NOAA scientist Amy Uhrin found a more accurate and efficient approach to measuring how much area was actually seagrass, rather than bare sand, in aerial images of coastal North Carolina. (NOAA)

To Uhrin’s excitement, the technique worked well, allowing her to accurately identify and map smaller patches of seagrass and export those maps to another computer program where she could precisely measure the distance between patches and determine the size, number, and orientation of seagrass patches in a given area.

“This now allows you to calculate how much of the polygon is actually seagrass vegetation,” said Uhrin, “which is good for fisheries management.” The young of many commercially important species, such as blue crabs, clams, and flounder, live in seagrass beds and actively use the plants. Young scallops, for example, cling to the blades of seagrass before sliding off and burrowing into the sediment as adults.

In addition, being able to better characterize the patterns of seagrass habitat could come in handy during coastal restoration planning and assessment. Due to local environmental conditions, some areas are more likely to produce patchy patterns in seagrass. As a result, efforts to restore seagrass habitat should aim for restoring not just cover but also the original spatial arrangement of the beds.

And, as Uhrin noted, having this information can “help address seagrass resilience in future climate change scenarios and altered hurricane regimes, as patchy seagrass areas are known to be more susceptible to storms than continuous meadows.”

The results of this study, which was done in concert with a colleague at the University of Wisconsin-Madison, have been published in the journal Estuarine, Coastal and Shelf Science.


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, where you also can view a video summary of his project.

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Births Down and Deaths Up in Gulf Dolphins Affected by Deepwater Horizon Oil Spill

A mother bottlenose dolphin pushes her dead newborn calf at the water's surface.

Dolphin Y01 pushes a dead calf through the waters of Barataria Bay, Louisiana, in March 2013. This behavior is sometimes observed in female dolphins when their newborn calf does not survive. Barataria Bay dolphins have seen a disturbingly low rate of reproductive success in the wake of the Deepwater Horizon oil spill. (Louisiana Department of Wildlife and Fisheries)

In August of 2011, a team of independent and government scientists evaluating the health of bottlenose dolphins in Louisiana’s Barataria Bay gave dolphin Y35 a good health outlook.

Based on the ultrasound, she was in the early stages of pregnancy, but unlike many of the other dolphins examined that summer day, Y35 was in pretty good shape. She wasn’t extremely underweight or suffering from moderate-to-severe lung disease, conditions connected to exposure to Deepwater Horizon oil in the heavily impacted Barataria Bay.

Veterinarians did note, however, that she had alarmingly low levels of important stress hormones responsible for behaviors such as the fight-or-flight response. Normal levels of these hormones help animals cope with stressful situations. This rare condition—known as hypoadrenocorticism—had never been reported before in dolphins, which is why it was not used for Y35 and the other dolphins’ health prognoses.

Less than six months later, researchers spotted Y35 for the last time. It was only 16 days before her expected due date. She and her calf are now both presumed dead, a disturbingly common trend among the bottlenose dolphins that call Barataria Bay their year-round home.

This trend of reproductive failure and death in Gulf dolphins over five years of monitoring after the 2010 Deepwater Horizon oil spill is outlined in a November 2015 study led by NOAA and published in the peer-reviewed journal Proceedings of the Royal Society.

Of the 10 Barataria Bay dolphins confirmed to be pregnant during the 2011 health assessment, only two successfully gave birth to calves that have survived. This unusually low rate of reproductive success—only 20%—stands in contrast to the 83% success rate in the generally healthier dolphins being studied in Florida’s Sarasota Bay, an area not affected by Deepwater Horizon oil.

Baby Bump in Failed Pregnancies

While hypoadrenocorticism had not been documented previously in dolphins, it has been found in humans. In human mothers with this condition, pregnancy and birth—stressful and risky enough conditions on their own—can be life-threatening for both mother and child when the condition is left untreated. Wild dolphins with this condition would be in a similar situation.

Mink exposed to oil in an experiment ended up exhibiting very low levels of stress hormones, while sea otters exposed to the Exxon Valdez oil spill experienced high rates of failed pregnancies and pup death. These cases are akin to what scientists have observed in the dolphins of Barataria Bay after the Deepwater Horizon oil spill.

Among the pregnant dolphins being monitored in this study, at least two lost their calves before giving birth. Veterinarians confirmed with ultrasound that one of these dolphins, Y31, was carrying a dead calf in utero during her 2011 exam. Another pregnant dolphin, Y01, did not successfully give birth in 2012, and was then seen pushing a dead newborn calf in 2013. Given that dolphins have a gestation of over 12 months, this means Y01 had two failed pregnancies in a row.

The other five dolphins to lose their calves after the Deepwater Horizon oil spill, excluding Y35, survived pregnancy themselves but were seen again and again in the months after their due dates without any young. Dolphin calves stick close to their mothers’ sides in the first two or three months after birth, indicating that these pregnant dolphins also had calves that did not survive.

At least half of the dolphins with failed pregnancies also suffered from moderate-to-severe lung disease, a symptom associated with exposure to petroleum products. The only two dolphins to give birth to healthy calves had relatively minor lung conditions.

Survival of the Least Oiled

Dolphin Y35 wasn’t the only one of the 32 dolphins being monitored in Barataria Bay to disappear in the months following her 2011 examination. Three others were never sighted again in the 15 straight surveys tracking these dolphins. Or rather, they were never seen again alive. One of them, Y12, was a 16-year-old adult male whose emaciated carcass washed up in Louisiana only a few weeks before the pregnant Y35 was last seen. In fact, the number of dolphins washing up dead in Barataria Bay from August 2010 through 2011 was the highest ever recorded for that area.

Survival rate in this group of dolphins was estimated at only 86%, down from the 95-96% survival seen in dolphin populations not in contact with Deepwater Horizon oil. The marshy maze of Barataria Bay falls squarely inside the footprint of the Deepwater Horizon oil spill, and its dolphins and others along the northern Gulf Coast have repeatedly been found to be sick and dying in historically high numbers. Considering how deadly this oil spill has been for Gulf bottlenose dolphins and their young, researchers expect recovery for these marine mammals to be a long time coming.

Watch an updated video of the researchers as they temporarily catch and give health exams to some of the dolphins in Barataria Bay, Louisiana, in August of 2011 and read a 2013 Q&A with two of the NOAA researchers involved in these studies:

This study was conducted under the Natural Resource Damage Assessment for the Deepwater Horizon oil spill. These results are included in the injury assessment documented in the Draft Programmatic Assessment and Restoration Plan that is currently out for public comment. We will accept comments on the plan through December 4, 2015.

This research was conducted under the authority of Scientific Research Permit nos. 779-1633 and 932-1905/MA-009526 issued by NOAA’s National Marine Fisheries Service pursuant to the U.S. Marine Mammal Protection Act.

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Deepwater Horizon Oil Spill Tied to Further Impacts in Shallower Water Corals, New Study Reports

Sick sea fan with discolored branches and hydroids covering it.

After the Deepwater Horizon oil spill, researchers found significant injuries in at least four species of sea fans along the Gulf’s continental shelf. Damage primarily took the form of overgrowth by hydroids (fuzzy marine invertebrates characteristic of unhealthy corals) and broken or bare branches of coral. (Credit: Ian MacDonald/Florida State University)

In the months and years after the 2010 Deepwater Horizon oil spill, damage and poor health were found in a swath of deep-sea coral reefs and related marine life at the bottom of the Gulf of Mexico.

Within roughly 16 miles of the leaking wellhead, researchers discovered sickened and damaged deep-sea corals, often coated in a clumpy brown material containing petroleum, and the sediments showed evidence of out-of-balance communities of tiny invertebrates inhabiting the seafloor sediments, whose diversity took a nose dive after the spill.

Now, a study published in October 2015 in the journal Coral Reefs reveals that this footprint of damage also extends to coral communities in shallower Gulf waters, up to 67 miles from the wellhead. In this latest study, researchers from NOAA, Florida State University, and JHT Inc. used video and images from remotely operated vehicles (ROV) to compare the health of corals on hard-bottom reefs in the “mesophotic zone” before and after the oil spill.

The mesophotic zone of the ocean receives low levels of light but supports abundant fish, corals, and sponges. The reefs in this study are important sources of habitat, food, and shelter for various marine life. These vibrant reefs also support recreational and commercial fishing for species such as snapper and grouper. Located in a region called the “Pinnacle Trend,” they are at the edge of the continental shelf off Louisiana, Mississippi, and Alabama, roughly 200-300 feet below the surface.

Previous oil spill studies focused on deep-sea coral communities 4,000 feet under the ocean, located near the leaking wellhead. While the Pinnacle Trend reefs are shallower and more remote, they were below the surface oil slick that persisted for several weeks.

What Lies Beneath

Three of the largest reefs at Pinnacle Trend—bearing the colorful names Alabama Alps Reef, Roughtongue Reef, and Yellowtail Reef—were located beneath the surface slick of Deepwater Horizon oil for three to five weeks in the summer of 2010. Located between 35 and 67 miles from the leaking well, corals on the reefs were likely to have been exposed to oil and dispersant that sank from the surface down toward the seafloor. These reefs were measured against two other reef sites more than 120 miles beyond the leaking well and below the Deepwater Horizon oil slick less than three days.

Graphic showing a profile of the Gulf of Mexico's seafloor habitats from shore out to the leaking wellhead.

A profile of the Gulf of Mexico seafloor habitats extending from the shore to depths around the Macondo wellhead. The mesophotic coral reefs in this study were located at the edge of the continental shelf. (NOAA/Kate Sweeney)

Because researchers had access to ROV footage of these coral reefs dating back as far as 1989, they could directly measure what level of injury could be considered “normal” for each reef. After all, this area of the Gulf is known to be susceptible to impacts from fishing methods that contact the sea bottom. Researchers suspect that fishing was the cause of injuries observed at the two sites far from the spill because lines were wrapped around many of the coral colonies.

Not a (Sea) Fan of Damaged Corals

The three reefs closer to the wellhead had less evidence of fishing but showed major declines in health after the oil spill in 2010. More than half of the coral colonies at these sites showed signs of damage by 2011, compared with less than 10% before the spill. In comparison, the sites further from the wellhead had no significant change before and after the Deepwater Horizon oil spill.

In addition, injured corals the scientists noted in 2011 continued to deteriorate in the years that followed, “suggesting recovery of injured corals is unlikely,” said lead author Dr. Peter Etnoyer of NOAA. Healthy corals noted after the incident in 2011 remained healthy through the end of the study in 2014, suggesting the injured corals would have been healthy but for the spill.

The researchers in this most recent study noted significant injuries among at least four species of large gorgonian octocorals (sea fans) in the three impacted reefs. Injuries took the form of overgrowth by hydroids (fuzzy marine invertebrates characteristic of unhealthy corals) and broken or bare branches of coral. To a lesser extent, corals also appeared severely discolored, with eroded polyps, had lost limbs, or toppled over entirely.

An earlier study of these mesophotic reefs by some of the same scientists in the journal Deep Sea Research detected low levels of a petroleum compound known as polycyclic aromatic hydrocarbons (PAHs) in coral tissues and nearby seafloor sediments. The levels were low compared to sites near the wellhead, but at this point, no one yet has established what constitutes a toxic level of these compounds to marine life in mesophotic coral communities.

“The corals of the Pinnacle Trend require decades to reach maturity,” said Florida State University scientist Ian MacDonald, who also contributed to the study. “Recovery will require years and it may not be immediately apparent whether the injured colonies are being replaced with new settlements. Our task is to study the process—to learn as much as we can and to ensure that nothing impedes this vital natural process.”

“The results presented here may vastly underestimate the extent of impacts to mesophotic reefs in the northern Gulf of Mexico,”  the researchers commented, since the reefs in this study represent less than 3 percent of the mesophotic reef habitat that was known to occur beneath the oil slick. “The reefs have some prospects for recovery since many healthy colonies remain,” said Etnoyer. NOAA and its partners on this study recommend efforts to protect and restore the Pinnacles Trend reefs in order to conserve the corals and fish along this part of the ocean floor.

Read more: At the Bottom of the Gulf of Mexico, Corals and Diversity Suffered After Deepwater Horizon Oil Spill


What Happens When Oil Spills Meet Massive Islands of Seaweed?

Floating bits of brown seaweed at ocean surface

Floating rafts of sargassum, a large brown seaweed, can stretch for miles across the ocean. (Credit: Sean Nash/Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic license)

The young loggerhead sea turtle, its ridged shell only a few inches across, is perched calmly among the floating islands of large brown seaweed, known as sargassum. Casually, it nibbles on the leaf-like blades of the seaweed, startling a nearby crab. Open ocean stretches for miles around these large free-floating seaweed mats where myriad creatures make their home.

Suddenly, a shadow passes overhead. A hungry seabird?

Taking no chances, the small sea turtle dips beneath the ocean surface. It dives through the yellow-brown sargassum with its tangle of branches and bladders filled with air, keeping everything afloat.

Home Sweet Sargassum

This little turtle isn’t alone in seeking safety and food in these buoyant mazes of seaweed. Perhaps nowhere is this more obvious than a dynamic stretch of the Atlantic Ocean off the East Coast of North America named for this seaweed: the Sargasso Sea. Sargassum is also an important part of the Gulf of Mexico, which contains the second most productive sargassum ecosystem in the world.

Some shrimp, crabs, and fish are specially suited to life in sargassum. Certain species of eel, fish, and shark spawn there. Each year, humpback whales, tuna, and seabirds migrate across these fruitful waters, taking advantage of the gathering of life that occurs where ocean currents converge.

Cutaway graphic of ocean with healthy sargassum seaweed habitat supporting marine life.

Illustration of sargassum and associated marine life, including fish, sea turtles, birds, and marine mammals. Sargassum is a brown algae that forms a unique and highly productive floating ecosystem on the surface of the open ocean. (NOAA) Click to enlarge.

The Wide and Oily Sargasso Sea

However, an abundance of marine life isn’t the only other thing that can accumulate with these large patches of sargassum. Spilled oil, carried by currents, can also end up swirling among the seaweed.

If an oil spill made its way somewhere like the Sargasso Sea, a young sea turtle would encounter a much different scene. As the ocean currents brought the spill into contact with sargassum, oil would coat those same snarled branches and bladders of the seaweed. The turtles and other marine life living within and near the oiled sargassum would come into contact with the oil too, as they dove, swam, and rested among the floating mats.

That oil can be inhaled as vapors, be swallowed or consumed with food, and foul feathers, skin, scales, shell, and fur, which in turn smothers, suffocates, or strips the animal of its ability to stay insulated. The effects can be toxic and deadly.

Cutaway graphic of ocean with potential impacts of oil on sargassum seaweed habitat and marine life.

Illustration of the potential impacts of an oil spill on sargassum and associated marine life in the water column. (NOAA) Click to enlarge.

While sea turtles, for example, as cold-blooded reptiles, may enjoy the relatively warmer waters of sargassum islands, a hot sun beating down on an oiled ocean surface can raise water temperatures to extreme levels. What starts as soothing can soon become stressful.

Depending on how much oil arrived, the sargassum would grow less, or not at all, or even die. These floating seaweed oases begin shrinking. Where will young sea turtles take cover as they cross the unforgiving open ocean?

As life in the sargassum starts to perish, it may drop to the ocean bottom, potentially bringing oil and the toxic effects with it. Microbes in the water may munch on the oil and decompose the dead marine life, but this can lead to ocean oxygen dropping to critical levels and causing further harm in the area.

From Pollution to Protection

Young sea turtles swims through floating seaweed mats.

The floating habitat that sargassum creates provides food, refuge, and breeding grounds for an array of marine species, including sea turtles. (NOAA)

NOAA and the U.S. Fish and Wildlife Service have designated sargassum as a critical habitat for threatened loggerhead sea turtles.

Sargassum has also been designated as Essential Fish Habitat by Gulf of Mexico Fishery Management Council and National Marine Fisheries Service since it also provides nursery habitat for many important fishery species (e.g., dolphinfish, triggerfishes, tripletail, billfishes, tunas, and amberjacks) and for ecologically important forage fish species (e.g., butterfishes and flyingfishes).

Sargassum and its inhabitants are particularly vulnerable to threats such as oil spills and marine debris due to the fact that ocean currents naturally tend to concentrate all of these things together in the same places. In turn, this concentrating effect can lead to marine life being exposed to oil and other pollutants for more extended periods of time and perhaps greater impacts.

However, protecting sargassum habitat isn’t impossible and it isn’t out of reach for most people. Some of the same things you might do to lower your impact on the planet—using less plastic, reducing your demand for oil, properly disposing of trash, discussing these issues with elected officials—can lead to fewer oil spills and less trash turning these magnificent islands of sargassum into floating islands of pollution.

And maybe protect a baby sea turtle or two along the way.