NOAA's Response and Restoration Blog

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

Leave a comment

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

As Ocean Conservancy’s Elizabeth Fetherston put it:

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

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

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

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

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

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

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

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

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

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

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

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

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

Leave a comment

Remembering the Veterans That Served America and the Historic Shipwrecks They Left Behind

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

Did you know that over 20,000 shipwrecks rest on the ocean floor off our coasts? The past century of commerce and warfare has left us with this legacy of sunken vessels dotting the seafloor around the United States.

While some of these are naval vessels, a large proportion are merchant vessels destroyed during war time. These wrecks are skewed heavily to World War II casualties such as those fallen during the “Battle of the Atlantic.” Some wrecks, such as the Civil War casualty, the USS Monitor, have been listed as National Historic Landmarks or on the National Register of Historic Places. Many of them, such as the USS Arizona at Pearl Harbor, Hawaii, are either civilian or military grave sites.

Beyond their military and historic significance, these wrecks also represent an enormous human toll. Today—on Veterans Day in the United States, Armistice Day or Remembrance Day in other nations—we honor the men and women who have served in the armed forces of all nations, as well as those serving in the Merchant Marine, and commemorate those who gave their lives in that service.

The Terrible Cost of the Battle of the Atlantic

During World War II’s Battle of the Atlantic, which lasted from September 1939 until the defeat of Germany in 1945, German U-boats and warships (and later Italian submarines) were pitted against Allied convoys transporting military equipment and supplies across the Atlantic to Great Britain and the Soviet Union. This battle to control Atlantic shipping lanes involved thousands of ships and stretched across thousands of square miles of ocean.

A Coast Guard ship's crew watches an explosion in the water ahead.

On April 17, 1943, Coast Guardsmen on the deck of the U.S. Coast Guard Cutter Spencer watch the explosion of a depth charge that blasted a Nazi U-boat’s hope of breaking into the center of a large convoy of ships. World War II left thousands of Allied and Axis ships — and soldiers — on the bottom of the ocean. (U.S. Coast Guard)

The losses in the battle were staggering. Between January and June 1942 alone, this battle resulted in the sinking of almost 500 ships. Historians estimate that more than 100 convoy battles took place during the war, costing Britain’s Merchant Navy more than 30,000 men and around 3,000 ships. The terrible cost for the Germans was 783 U-boats and 28,000 sailors, about 75% of the U-boat force. Although casualty statistics vary, we know that the U.S. Merchant Mariners suffered the highest rate of marine casualties of any service in World War II.

While many of these sunken vessels in U.S. waters rest in the Atlantic Ocean or Gulf of Mexico, numerous wrecks, such as the S/S Montebello, can be found in the Pacific. And of course, the wartime toll was spread across the world’s oceans, touching nearly all parts of the globe.

NOAA’s Role with Undersea Wrecks

NOAA is involved with shipwrecks in a number of ways. The agency’s role ranges from offering scientific guidance to the U.S. Coast Guard during pollution responses, to stewarding the diverse natural and cultural resources including shipwrecks in national marine sanctuaries, to creating navigational charts that show the precise locations of wrecks that could hinder maritime traffic. Most of the 20,000 wrecks resting off our coasts are old and did not carry oil as fuel or hazardous cargo; however, some of the more recent wrecks have the potential to contain—and sometimes leak—oil.

In 2002, for example, the decaying wreck of the S/S Jacob Luckenbach (carrying supplies to support the Korean War) was identified as the source of mysterious, recurring oil spills that had killed thousands of seabirds and other marine life along California’s coast. Our office joined with the U.S. Coast Guard and other agencies to remove the approximately 100,000 gallons of oil remaining in the wreck, protect the resources of the Great Farallones National Marine Sanctuary, and restore critical seabird breeding habitat in the U.S. and Canada to make up for the harm caused by the oil releases.

Two divers and a shark swim next to a large shipwreck.

Knowing how shipwreck sites formed helps explain why sunken vessels, like the Dixie Arrow which initially carried approximately 86,136 barrels of crude oil, but was demolished during World War II, no longer remain intact and are no longer potentially polluting shipwrecks. (NOAA)

Leaking wrecks like the Jacob Luckenbach are one reason NOAA maintains a large database of shipwrecks, dumpsites, navigational obstructions, underwater archaeological sites, and other underwater cultural resources, known as the Resources and Undersea Threats (RUST) database.

Beginning in 2010, NOAA’s Office of Response and Restoration and Office of National Marine Sanctuaries systematically analyzed a subset of those wrecks which could pose a substantial threat of leaking oil still on board. This work is part of NOAA’s Remediation of Underwater Legacy Environmental Threats (RULET) project. (Read more about the work conducted and the final report (PDF).) After the report was completed in 2013, the U.S. Coast Guard has worked to incorporate the information and recommendations into their regional contingency plans.

NOAA also has the privilege of protecting shipwrecks and naval battlefields though its National Marine Sanctuaries office. The first NOAA national marine sanctuary was designated in 1975 to protect the U.S. Navy warship USS Monitor, and other sanctuaries have followed in these footsteps of preserving historic wrecks. Today, you can explore fascinating undersea wrecks at Florida Keys National Marine Sanctuary, Thunder Bay National Marine Sanctuary in the Great Lakes, and at other sanctuaries.

Wrecks and Reefs

Sometimes these submerged shipwrecks can serve as artificial reefs. Sunken wrecks are actually the most prevalent type of artificial reef. As artificial reefs, shipwrecks can create both amazing homes for a diversity of marine life and popular attractions for commercial and recreational fishers, divers, and snorkelers.

Occasionally, vessels are even sunk intentionally for this purpose. However, it can be very costly to prepare the vessels to become artificial reefs, which requires removing paints and other hazardous materials in the hull. Another consideration is the stability of the vessel and its danger to living things around it. For example, if the vessel is in shallow water, will it flip over in a storm and crush the new coral growing there? Could people or marine life get caught inside it? These considerations are why artificial reefs are often found in deep water and why establishing an artificial reef requires special review and permitting processes.

Through the study, protection, and promotion of our diverse legacy of undersea wrecks, national marine sanctuaries help us learn more about and celebrate our merchant marine and military history.

Explore Shipwrecks While Staying Dry

You can learn more about NOAA expeditions between 2008 and 2011, which explored the World War II wrecks in the “Graveyard of the Atlantic.”

You also can watch a video of researchers first discovering the long-lost location of the USS Monitor’s wreck in 1973 off the coast of North Carolina:

See what it’s like to dive among the many wrecks at the bottom of Lake Huron in Thunder Bay’s “Shipwreck Alley”:

Take a video tour of the wreck of the USS Arizona, sunk by Japanese planes on December 7, 1941, and pay homage to the members of the U.S. armed forces who gave their lives.

Video frame of a diver exploring a shipwreck.

Donna Roberts

Donna Roberts

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

1 Comment

How Does Oil Get into the Ocean?

Oil rig in the Gulf of Mexico.

Oil rig in the Gulf of Mexico, off the coast of Port Fourchon, Louisiana. A 2003 report from the National Academy of Sciences estimates 3% of the oil entering the ocean each year comes from oil and gas exploration and extraction activities. (NOAA)

When many of us think of oil spills, we might think of an oil tanker running aground and spilling its contents into the ocean, as in the case of the oil tanker Exxon Valdez when the ship ran aground near the coast of Alaska in 1989.

In fact, there are actually several ways crude or refined oil may reach the marine environment. All of those spills add up too. In a 2003 publication, the National Research Council of the National Academy of Sciences reported that roughly 343,200,000 gallons of oil were released into the sea annually, worldwide. Of this amount, the report estimates the origin of that oil as follows:

  • Use or consumption of oil (which includes operational discharges from ships and discharges from land-based sources): 37%
  • Transportation (accidental spills from ships): 12%
  • Extraction: 3%
  • Natural seeps: 46%

Wherever oil is consumed, such as in manufacturing or when loading a ship with fuel, there are opportunities for oil spills. According to the Washington State Department of Ecology [PDF], most spills that occur during ship fueling happen because of inattention, inadequate procedure, procedural error, or poor judgment—in other words, human error.

The typically small-in-size spills that come from consuming oil originate from a variety of activities and actually account for most of the oil spilled by humans into the sea.

When the Exxon Valdez oil spill occurred, on the other hand, crude oil was in transport. Since oil is an international commodity and in constant demand, there are always ships, pipelines, and (increasingly) trains moving it around the world. According to the International Tanker Owners Pollution Federation, occurrences of large spills from tankers and barges (above approximately 2,000 gallons) have decreased dramatically since 1970. This can be attributed at least in part to advances in safety thanks to the Oil Pollution Act of 1990.

While oil extraction is not considered a large source of the overall amount of oil released into the sea each year, spills from offshore oil exploration and drilling can be huge when they do happen. The well blowout that caused Deepwater Horizon spill in the Gulf of Mexico in 2010 is a (very large) example of an oil spill occurring during extraction activities. This type of accident occurs only where oil exploration and drilling operations take place—in the United States, the Gulf of Mexico and waters off the southern California coast are the major areas.

Dark, thick oil seeps out of the ocean floor sediments.

A natural tar seep releases oil offshore from Gaviota, California. When an oil spill occurs in an area with many naturally occurring seeps, responders may have a difficult time telling spilled oil apart from seep oil. (Donna Schroeder/U.S. Geological Survey)

While not technically “oil spills,” oil seeps from the ocean floor naturally release oil from subterranean reservoirs and represent the largest source of oil entering seas both in the United States and around the world. Even though seeps are not without their own impacts on marine life, natural oil seeps release oil slowly over time, allowing ecosystems to adapt. During an oil spill, the amount of oil released in a short time can overwhelm an ecosystem.

Impact, then, is not only determined by how much oil is in the environment, but also the type of oil and how quickly it is released.

The May 2015 oil spill at Refugio State Beach was caused by a pipeline break near Santa Barbara, California, adjacent to Coal Oil Point, a region famous for its natural seeps. Oil from seeps there release an estimated 6,500-7,000 gallons of oil per day (Lorenson et al., 2011) and are among the most active in the world. One of the response challenges during that spill was distinguishing between the oil that flowed directly into the ocean from the pipeline break and that from the ongoing seeps.

For a quick glance at the major causes of oil spills in the ocean, check out our infographic:

Graphic showing buildings and cars using oil, a tanker transporting oil, and a rig drilling for oil in the ocean, with a natural seep leaking oil out of the seafloor. Use of oil: Anywhere crude or refined oil is stored or used, such as for fuel or in manufacturing, there is risk of a spill. Transportation of oil: Crude oil is an international commodity, and as it is moved around the world, it may be spilled from storage tanks, barges, pipelines, and other bulk transport. Extraction of oil: Oil exploration and extraction from the ground or below the ocean surface potentially could release oil into the environment. Natural seeps of oil: Oil seeps are natural leaks of crude oil and gas from subterranean reservoirs through the ocean floor. While not caused by humans, oil from seeps can be confused with oil spills.

There are four primary ways oil can end up in the ocean: natural seeps, consumption, extraction, and transportation of oil. (NOAA)

Leave a comment

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.

Leave a comment

Visualizing How Ocean Currents Help Create the Garbage Patches

Plastic water bottle floating in the ocean.

The “garbage patches” are not giant, floating islands of trash, but rather, ocean gathering places for what are mainly tiny bits of plastic dispersed throughout the water column, with some larger items as well. (NOAA)

The data whizzes at NASA recently decided to turn their attention from the sky to the ocean as they attempted to model how ocean currents help drive the formation of the “garbage patches.” From NASA:

“We start with data from floating, scientific buoys that NOAA has been distributing in the oceans for the last 35 years represented here as white dots … If we let all of the buoys go at the same time, we can observe buoy migration patterns … The buoys migrate to 5 known gyres also called ocean garbage patches.

We can also see this in a computational model of ocean currents called ECCO-2. We release particles evenly around the world and let the modeled currents carry the particles. The particles from the model also migrate to the garbage patches.”

Check out their data visualization here:

As you might gather from the visualization, the gyres, where “garbage patches” are located, represent massive, dynamic areas of the ocean that are constantly moving and changing—and as a result, are also bringing trash and other marine debris with them. Rather than giant, floating islands of trash that you can see from satellites (you can’t), “garbage patches” are ocean gathering places for what are mainly tiny bits of plastic dispersed throughout the water column.

Still fuzzy on what the garbage patches are and are not? Check out this video from the NOAA Marine Debris Program:

And tune in to this National Ocean Service podcast to learn what we know and don’t know about the garbage patches and what we can do about this ocean-sized problem:

You can also read about our own efforts to model where marine debris travels across the ocean.

Leave a comment

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.


Watch Divers Restore Coral Reefs Hit by a Huge Ship in Hawaii

Coral reefs are not to be confused with underwater highways. Unfortunately for the corals, however, navigating huge ships is a tricky business and sometimes reefs do end up on the wrong side of the “road.” (One reason why having up-to-date navigational charts is so important!)

This was the case for corals 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.

NOAA’s Restoration Center and the State of Hawaii worked quickly to implement emergency restoration (using what look like laundry baskets), using special underwater scientific techniques and technologies, and ultimately restoring the reef after getting some help from vacuums, power washers, and even winter storms.

See divers transform these Hawaiian corals from crushed to flush with marine life:

In the end, these efforts are all part of how we work to help make the ocean a better place for corals and the many other types of marine life that rely on them.


Get every new post delivered to your Inbox.

Join 631 other followers