Archive for November 2015

In the Wake of the Deepwater Horizon Oil Spill, Gulf Dolphins Found Sick and Dying in Larger Numbers Than Ever Before | response.restoration.noaa.gov

Gulf Dolphins Found Sick and Dying in Larger Numbers Than Ever Before

Dolphin with oil on its skin swimming.

A dolphin is observed with oil on its skin on August 5, 2010, in Barataria Bay, Louisiana. (Louisiana Department of Wildlife and Fisheries/Mandy Tumlin)

The Deepwater Horizon Oil Spill: Five Years Later

This is the third in a series of stories over the coming weeks looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

APRIL 3, 2015 — Dolphins washing up dead in the northern Gulf of Mexico are not an uncommon phenomenon.

What has been uncommon, however, is how many moredead bottlenose dolphins have been observed in coastal waters affected by the Deepwater Horizon oil spill in the five years since. In addition to these alarmingly high numbers, researchers have found that bottlenose dolphins living in those areas are in poor health, plagued by chronic lung disease and failed pregnancies.

Independent and government scientists have undertaken a number of studies to understand how this oil spill may have affected dolphins, observed swimming through oil and with oil on their skin, living in waters along the Gulf Coast. These ongoing efforts have included examining and analyzing dead dolphins stranded on beaches, using photography to monitor living populations, and performing comprehensive health examinations on live dolphins in areas both affected and unaffected byDeepwater Horizon oil.

The results of these rigorous studies, which recently have been and continue to be published in peer-reviewed scientific journals, show that, in the wake of the 2010 Deepwater Horizon oil spill and in the areas hardest hit, the dolphin populations of the northern Gulf of Mexico have been in crisis.

Troubled Waters

Left, scientists taking a blood sample from one dolphin in the water and right, a team of researchers in the water photographs a dolphin’s dorsal fin against a white square.

Left, in 2011 veterinary scientists took blood samples from bottlenose dolphins in Barataria Bay, Louisiana, as part of an overall health assessment. Right, the same team of researchers photographed dolphins’ dorsal fins as a means of identifying individuals and monitoring populations in the wake of the Deepwater Horizon oil spill. (NOAA)

Due south of New Orleans, Louisiana, and northwest of the Macondo oil well that gushed millions of barrels of oil for 87 days, lies Barataria Bay. Its boundaries are a complex tangle of inlets and islands, part of the marshy delta where the Mississippi River meets the Gulf of Mexico and year-round home to a group of bottlenose dolphins.

During the Deepwater Horizon oil spill, this area was one of the most heavily oiled along the coast. Beginning the summer after the spill, record numbers of dolphins started stranding, or coming ashore, often dead, in Barataria Bay (Venn-Watson et al. 2015). One period of extremely high numbers of dolphin deaths in Barataria Bay, part of the ongoing, largest and longest-lasting dolphin die-off recorded in the Gulf of Mexico, persisted from August 2010 until December 2011.

In the summer of 2011, researchers also measured the health of dolphins living in Barataria Bay, comparing them with dolphins in Sarasota Bay, Florida, an area untouched by the Deepwater Horizonoil spill.

Differences between the two populations were stark.

Many Barataria Bay dolphins were in very poor health, some of them significantly underweight and five times more likely to have moderate-to-severe lung disease. Notably, the dolphins of Barataria Bay also were suffering from disturbingly low levels of key stress hormones which could prevent their bodies from responding appropriately to stressful situations. (Schwacke et al. 2014)

“The magnitude of the health effects that we saw was surprising,” said NOAA scientist Dr. Lori Schwacke, who helped lead this study. “We’ve done these health assessments in a number of locations across the southeast U.S. coast and we’ve never seen animals that were in this poor of condition.”

The types of illnesses observed in live Barataria Bay dolphins, which had sufficient opportunities to inhale or ingest oil following the 2010 spill, match those found in people and other animals also exposed to oil. In addition, the levels of other pollutants, such as DDT and PCBs, which previously have been linked to adverse health effects in marine mammals, were much lower in Barataria Bay dolphins than those from the west coast of Florida.

Dead in the Water

Based on findings from the 2011 study, the outlook for dolphins living in one of the most heavily oiled areas of the Gulf was grim. Nearly 20 percent of the Barataria Bay dolphins examined that year were not expected to live, and in fact, the carcass of one of them was found dead less than six months later (Schwacke et al. 2014). Scientists have continued to monitor the dolphins of Barataria Bay to document their health, survival, and success giving birth.

Left, dolphin Y12 during a health assessment in August 2011 and right, after his carcass was recovered in January 2012.

Left, August 2011: Veterinarians collect a urine sample from Y12, a 16-year-old adult male bottlenose dolphin caught near Grand Isle, LA. Y12’s health evaluation determined that he was significantly underweight, anemic, and had indications of liver and lung disease. (NOAA) Right, January 2012: The carcass of Y12 was recovered on Grand Isle Beach. The visible ribs, prominent vertebral processes and depressions along the back are signs of extreme emaciation. (Louisiana Department of Wildlife and Fisheries)

Considering these health conditions, it should come as little surprise that record high numbers of dolphins have been dying along the coasts of Louisiana (especially Barataria Bay), Alabama, and Mississippi. This ongoing, higher-than-usual marine mammal die-off, known as an unusual mortality event, has lasted over four years and claimed more than a thousand marine mammals, mostly bottlenose dolphins. For comparison, the next longest lasting Gulf die-off (in 2005–2006) ended after roughly a year and a half (Litz et al. 2014 [PDF]).

Researchers studying this exceptionally long unusual mortality event, which began in February 2010, identified within it multiple distinct groupings of dolphin deaths. All but one of them occurred after the Deepwater Horizon oil spill, which released oil from April to July 2010, and corresponded with areas exposed heavily to the oil, particularly Barataria Bay (Venn-Watson et al. 2015).

In early 2011, the spring following the oil spill, Mississippi and Alabama saw a marked increase in dead dolphin calves, which either died late in pregnancy or soon after birth, and which would have been exposed to oil as they were developing.

The Gulf coasts of Florida and Texas, which received comparatively little oiling from the Deepwater Horizon spill, did not see the same significant annual increases in dead dolphins as the other Gulf states (Venn-Watson et al. 2015). For example, Louisiana sees an average of 20 dead whales and dolphins wash up each year, but in 2011 alone, this state recorded 163 (Litz et al. 2014 [PDF]).

The one grouping of dolphin deaths starting before the spill, from March to May 2010, took place in Louisiana’s Lake Pontchartrain (a brackish lagoon) and western Mississippi. Researchers observed both low salinity levels in this lake and tell-tale skin lesions thought to be associated with low salinity levels on this group of dolphins. This combined evidence supports that short-term, freshwater exposure in addition to cold weather early in 2010 may have been key contributors to those dolphin deaths prior to the Deepwater Horizon spill.

Legacy of a Spill?

A bottlenose dolphin swims in the shallow waters along a sandy beach with orange oil boom.

A bottlenose dolphin swims in the shallow waters along the beach in Grand Isle, Louisiana, near oil containment boom that was deployed on May 28, 2010. Oil from the Deepwater Horizon oil spill began washing up on beaches here one month after the drilling unit exploded. (U.S. Coast Guard)

In the past, large dolphin die-offs in the Gulf of Mexico could usually be tied to short-lived, discrete events, such as morbillivirus and marine biotoxins (resulting from harmful algal blooms). While studies are ongoing, the current evidence does not support that these past causes are responsible for the current increases in dolphin deaths in the northern Gulf since 2010 (Litz et al. 2014).

However, the Deepwater Horizon oil spill—its timing, location, and nature—offers the strongest evidence for explaining why so many dolphins have been sick and dying in the Gulf since 2010. Ongoing studies are assessing disease among dolphins that have died and potential changes in dolphin health over the years since the spill.

As is the case for deep-sea corals, the full effects of this oil spill on the long-lived and slow-to-mature bottlenose dolphins and other dolphins and whales in the Gulf may not appear for years. Find more information related to dolphin health in the Gulf of Mexico on NOAA’s Unusual Mortality Event andGulf Spill Restoration websites.

By Ashley Braun, NOAA’s Office of Response and Restoration Web Editor.

Source: In the Wake of the Deepwater Horizon Oil Spill, Gulf Dolphins Found Sick and Dying in Larger Numbers Than Ever Before | response.restoration.noaa.gov

Why PADI Divemasters Rock | Sport Diver

PADI Divemasters Rock

 They’re always there when you need them. See who’s giving a shoutout to their favorite PADI Divemaster.

Even for those who didn’t struggle, a Divemaster may have helped render your dives safer by ensuring your gear was donned correctly and buddy checks were properly conducted. For example, PADI Diver Patrick Loerbach wrote to PADI about the Divemaster who assisted him during his PADI Advanced Open Water Diver course at PADI Five Star Career Development Center Couples Resort in St. Ann, Jamaica, last summer.

“Divemaster Collin Whyte was always happy, chatty — and busy! He did such a great job of keeping us laughing that it was several dives before I came to see how organized and detailed he was in preparing the equipment, knowing the skills and experience of each diver, and making sure everyone was safe and comfortable. He was a stickler for making sure ascents and descents were done properly, and he had a knack for spotting cool things that we missed. Having Collin there always made for a better dive.”

First-Rate Boat Mates

Going on a boat dive? Don’t forget to bring along your favorite PADI Divemaster.

A Divemaster is often the person on the boat who assists you in getting ready to dive, from helping you set up your gear to making sure your air is on before you take that giant stride into the water. When you were new, it was most likely a Divemaster who helped you with your predive jitters by telling you funny stories. Once underwater, he led you to the best places to see the coolest creatures, helping you forget your nerves. Or, perhaps he trailed the dive group, ready to assist if needed, while ensuring the group stayed together and everyone returned safely back to the boat. Better still, at the end of your dive, it was probably the Divemaster who eased your passage out of the water by taking your fins and any other equipment you may have needed to hand off before climbing the ladder.

Are You Hero Material?

Aside from being heroically helpful, PADI Divemasters get to do some cool stuff — like live the dive life every day. They can travel the world, seeking employment at more than 6,200 PADI Dive Centers and Resorts; leading Discover Local Diving excursions, snorkeling tours and select PADI Adventure Dives; and teaching PADI ReActivate, PADI’s new scuba-refresher program. Divemasters can also apply to become Discover Scuba Diving leaders, Underwater Photographer instructors or Emergency Oxygen Provider instructors.

If you think you’d like to become a PADI Divemaster, visit padi.com for prerequisites for the course. If you meet the requirements, you can start your Divemaster program today with the PADI Divemaster Online course, or by enrolling at your local PADI Dive Center or Resort.

Source: Why PADI Divemasters Rock | Sport Diver

Largest Oil Spills Affecting U.S. Waters Since 1969 | response.restoration.noaa.gov

Oil Spills Affecting U.S. Waters Since 1969

Thousands of oil spills occur in U.S. waters each year, but most are small in size, spilling less than one barrel of oil.

Yet since the iconic 1969 oil well blowout in Santa Barbara, California, there have been at least 44 oil spills over 10,000 barrels (420,000 gallons) affecting U.S. waters. The largest of which was the 2010Deepwater Horizon well blowout in the Gulf of Mexico.

NOAA’s Office of Response and Restoration has created the following graphic listing these spills based on records and information from its Emergency Response Division. While every effort has been made to develop a complete list, there may be additional incidents that NOAA was not involved in responding to and therefore are not represented here.

This graphic also is focused on oil spills on or into U.S. navigable waters, which excludes terrestrial and underground spills. Spill volumes may be inexact due to the causes of some incidents, such as fire, sinking, and hurricanes.

In addition, even relatively small oil spills can cause major environmental and economic harm, depending on location, season, environmental sensitivity, and type of oil. As a result, this graphic also includes examples of major U.S. oil spills less than 10,000 barrels.

Map showing location and relative size of largest oil spills affecting U.S. waters since 1969.

                                                                                Largest oil spills affecting U.S. waters since 1969 (NOAA) Click to enlarge.

 

 

Source: Largest Oil Spills Affecting U.S. Waters Since 1969 | response.restoration.noaa.gov

Posted Sunday, 1 November 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

Attempting to Answer One Question Over and Over Again: Where Will the Oil Go?

 Where Will the Oil Go?

A heavy band of oil is visible on the surface of the Gulf of Mexico.

A heavy band of oil is visible on the surface of the Gulf of Mexico during an overflight of the Deepwater Horizon oil spill on May 12, 2010. Predicting where oil like this will travel depends on variable factors including wind and currents. (NOAA)

 

Overflight surveys from airplanes or helicopters help responders find oil slicks as they move and break up across a potentially wide expanse of water. They give snapshots of where the oil is located and how it is behaving at a specific date and time, which NOAA uses to compare to our oceanographic models. (U.S. Coast Guard)

 

Two people in a helicopter over water.

The Deepwater Horizon Oil Spill: Five Years Later

This is the first in a series of stories over the coming weeks looking at various topics related to the response, the Natural Resource Damage Assessment science, restoration efforts, and the future of the Gulf of Mexico.

MARCH 30, 2015 — Oil spills raise all sorts of scientific questions, andNOAA’s job is to help answer them.

We have a saying that each oil spill is unique, but there is one question we get after almost every spill: Where will the oil go? One of our primary scientific products during a spill is a trajectory forecast, which often takes the form of a map showing where the oil is likely to travel and which shorelines and other environmentally or culturally sensitive areas might be at risk.

Oil spill responders need to know this information to know which shorelines to protect with containment boom, or where to stage cleanup equipment, or which areas should be closed to fishing or boating during a spill.

To help predict the movement of oil, wedeveloped the computer model GNOME to forecast the complex interactions among currents, winds, and other physical processes affecting oil’s movement in the ocean. We update this model daily with information gathered from field observations, such as those from trained observers tasked with flying over a spill to verify its often-changing location, and new forecasts for ocean currents and winds.

Modeling a Moving Target

One of the biggest challenges we’ve faced in trying to answer this question was, not surprisingly, the 2010 Deepwater Horizon oil spill. Because of the continual release of oil—tens of thousands of barrels of oil each day—over nearly three months, we had to prepare hundreds of forecasts as more oil entered the Gulf of Mexico each day, was moved by ocean currents and winds, and was weathered, or physically, biologically, or chemically changed, by the environment and response efforts.

A typical forecast includes modeling the outlook of the oil’s spread over the next 24, 48, and 72 hours. This task began with the first trajectory our oceanographers issued early in the morning April 21, 2010 after being notified of the accident, and continued for the next 107 days in a row. (You canaccess all of the forecasts from this spill online.)

Once spilled into the marine environment, oil begins to move and spread surprisingly quickly but not necessarily in a straight line. In the open ocean, winds and currents can easily move oil 20 miles or more per day, and in the presence of strong ocean currents such as the Gulf Stream, oil and other drifting materials can travel more than 100 miles per day. Closer to the coast, tidal currents also can move and spread oil across coastal waters.

While the Deepwater Horizon drilling rig and wellhead were located only 50 miles offshore of Louisiana, it took several weeks for the slick to reach shore as shifting winds and meandering currents slowly moved the oil.

A Spill Playing on Loop

Over the duration of a typical spill, we’ll revise and reissue our forecast maps on a daily basis. These maps include our best prediction of where the oil might go and the regions of highest oil coverage, as well as what is known as a “confidence boundary.” This is a line encircling not just our best predictions for oil coverage but also a broader area on the map reflecting the full possible range in our forecasts [PDF].

Our oceanographers include this confidence boundary on the forecast maps to indicate that there is a chance that oil could be located anywhere inside its borders, depending on actual conditions for wind, weather, and currents.

Why is there a range of possible locations in the oil forecasts? Well, the movement of oil is very sensitive to ocean currents and wind, and predictions of oil movement rely on accurate predictions of the currents and wind at the spill site. In addition, sometimes the information we put into the model is based on an incomplete picture of a spill. Much of the time, the immense size of the Deepwater Horizon spill on the ocean surface meant that observations from specialists flying over the spill and even satellites couldn’t capture the full picture of where all the oil was each day.

Left, woman pointing and explaining maps on desk to man. Right, dark brown and red oil on ocean surface with two response ships.

Forecasters attempt to assess all the possible outcomes for a given scenario, estimate the likelihood of the different possibilities, and ultimately communicate risks to the decision makers. Left, NOAA oceanographer Amy MacFadyen explains how NOAA creates oil trajectory maps to then-Department of Commerce Secretary Gary Locke. Photo at right taken on May 27, 2010 near an ocean convergence zone shows dark brown and red emulsified oil from the Deepwater Horizon oil spill. The movement of oil is very sensitive to ocean currents and wind, and the size of this spill further complicated our attempts to model where the oil would go. (NOAA)

Our inevitably inexact knowledge of the many factors informing the trajectory model introduces a certain level of expected variation in its predictions, which is the situation with many models. Forecasters attempt to assess all the possible outcomes for a given scenario, estimate the likelihood of the different possibilities, and ultimately communicate risks to the decision makers.

In the case of the Deepwater Horizon oil spill, we had the added complexity of a spill that spanned many different regions—from the deep Gulf of Mexico, where ocean circulation is dominated by the swift Loop Current, to the continental shelf and nearshore area where ocean circulation is influenced by freshwater flowing from the Mississippi River.  And let’s not forget that several tropical storms andhurricanes crossed the Gulf that summer [PDF].

A big concern was that if oil got into the main loop current, it could be transported to the Florida Keys, Cuba, the Bahamas, or up the eastern coast of the United States. Fortunately (for the Florida Keys) a giant eddy formed in the Gulf of Mexico in June 2010 (nicknamed Eddy Franklin after Benjamin Franklin, who did some of the early research on the Gulf Stream). This “Eddy Franklin” created a giant circular water current that kept the oil largely contained in the Gulf of Mexico.

Some of the NOAA forecast team likened our efforts that spring and summer to the movie Groundhog Day, in which the main character is forced to relive the same day over and over again. For our team, every day involved modeling the same oil spill again and again, but with constantly changing results.

Thinking back on that intense forecasting effort brings back memories packed with emotion—and exhaustion. But mostly, we recall with pride the important role our forecast team in Seattle played in answering the question “where will the oil go?”

By Doug Helton, NOAA’s Office of Response and Restoration Incident Operations Coordinator.

Source: Attempting to Answer One Question Over and Over Again: Where Will the Oil Go? | response.restoration.noaa.gov

Dive Life: Girls Just Wanna Change the World

Our sport was once a male-dominated pursuit, but women are changing the face of the scuba diving. To celebrate PADI is launching Women’s Dive Day.

What was once a male-dominated sport has become a woman’s realm.

While diving once might have been considered a male pursuit, women are changing the face of our sport. Dr. Sylvia Earle was more than just a 2014 Glamour Woman of the Year; she was also deemed the first Hero for the Planet by Time magazine, and designated a Living Legend by the Library of Congress. The member roster of the Women Divers Hall of Fame is filled with similar women who have shaped the world of diving. It’s time to celebrate female divers’ contributions to the sport, so PADI is launching Women’s Dive Day on July 18 to honor them.

Women to Watch

Szilvia Gogh is a well-known underwater stunt woman and founder of Miss Scuba (miss-scuba.com), which was designed to bring together women who share an enthusiasm for diving from all over the world. She was also one of the youngest women ever accepted into the PADI Course Director Training Course and recently held a female-friendly course to develop the next generation of Dive Instructors. “What inspired them to become PADI Professionals, I believe, was that they saw me live out my dreams,”says Gogh. “I get to do what I love and, to me, this means everything.”

For others, like Georgienne Bradley, diving helped marry interests in biology and photography. She was instrumental in helping Cocos Island become a UNESCO World Heritage Site. One of her proudest achievements though has been her involvement in scholar expeditions for young girls. “These trips allow girls to open up, not be intimidated, and come into their own,” says Bradley.

The women of SEDNA Epic Expedition (sednaepic.com) are another great example. Expedition leader Susan R. Eaton is surrounded by a team of female scientists, explorers and photographers who will embark on a 1,864-mile journey, snorkeling from Pond Inlet, Nunavut, to Inuvik, Northwest Territories in Canada. Their goal is to increase awareness of climate change and to inspire action, especially among youth and women.

A Day to Remember

If you’re interested in organizing an event or participating in a local dive for Women’s Dive Day, please send an email to womendive@padi.com or visit padi.com/women-dive.

Source: Dive Life: Girls Just Wanna Change the World | Sport Diver

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

Spike in Gulf of Mexico 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)

Using ultrasound to examine the lungs of live dolphins in Barataria Bay, Louisiana. “These dolphins had some of the most severe lung lesions I have seen in the over 13 years that I have been examining dead dolphin tissues from throughout the United States,” said Dr. Kathleen Colegrove, the study’s lead veterinary pathologist based at the University of Illinois.

MAY 20, 2015 — What has been causing the alarming increase in dead bottlenose dolphins along the northern Gulf of Mexico since theDeepwater Horizon oil spill in the summer of 2010?People taking an ultrasound of a dolphin's lungs.

Independent and government scientists have found even more evidenceconnecting these deaths to the same signs of illness found in animals exposed to petroleum products, as reported in the peer-reviewed online journalPLOS 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 ofNOAA’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

Boats with nets to capture dolphins in the ocean.

An earlier study described health examinations on live dolphins in Barataria Bay, one of the heaviest oiled parts of the Gulf of Mexico, in 2011, which found evidence of poor health, adrenal disease, and lung disease consistent with petroleum product exposure. (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.

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)

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.

Source: Latest NOAA Study Ties Deepwater Horizon Oil Spill to Spike in Gulf Dolphin Deaths | response.restoration.noaa.gov

What Happens When Oil Spills Meet Massive Islands of Seaweed?

Floating rafts of sargassum, a large brown seaweed, can stretch for miles across the ocean.

Floating bits of brown seaweed at ocean surface
                                                            (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.

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.

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.

NOAA and the U.S. Fish and Wildlife Service havedesignated 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.

Source: What Happens When Oil Spills Meet Massive Islands of Seaweed?

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