NOAA's Response and Restoration Blog

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


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Debunking the Myths about Garbage Patches

This week, NOAA’s Office of Response and Restoration is looking at some common myths and misconceptions surrounding oil spills, chemical releases, and marine debris.

Garbage floating on water as seen from underneath.

You may have envisioned the garbage patches looking something like this, but that’s pretty far from the truth. (NOAA)

Although most of us have heard the term “garbage patch” before, many may not have a full understanding of what the term really means. In recent years, there has been a lot of misinformation spread about garbage patches and so now, we are here to try to clear up some of these myths.

First, what are garbage patches? Well, garbage patches are areas of increased concentration of marine debris that are formed from rotating ocean currents called gyres and although they may not be as famous as the “Great Pacific Garbage Patch,” there are actually several garbage patches around the world! So let’s address some of the most common questions and misconceptions about garbage patches:

Are garbage patches really islands of trash that you can actually walk on?

Nope! Although garbage patches have higher amounts of marine debris, they’re not “islands of trash” and you definitely can’t walk on them. The debris in the garbage patches is constantly mixing and moving due to winds and ocean currents. This means that the debris is not settled in a layer at the surface of the water, but can be found from the surface, throughout the water column, and all the way to the bottom of the ocean.

Ocean with horizon.

It possible to sail through a garbage patch without even realizing it! (NOAA)

Not only that, the debris within the garbage patches is primarily microplastics, tiny plastic pieces less than five millimeters in size. Many of these microplastics are the result of larger plastic debris that has broken into small pieces from exposure to the sun, salt, wind, and waves. Others, such as microbeads from products like facewashes or microfibers from synthetic clothing, are already small in size when they enter the water. With such small debris items making up the majority of the garbage patches and the constant movement of this debris, it’s possible to sail through a garbage patch without even realizing it.

 

The Great Pacific Garbage Patch is the size of Texas and you can see it from space!

Not so much. Since the garbage patches are constantly moving and mixing with winds and ocean currents, their size continuously changes. They can be very large, but since they’re made up primarily of microplastic debris, they definitely can’t be seen from space.

Why don’t we just clean them up?

Unfortunately, cleaning up the garbage patches is complicated. Since the debris making them up is not only constantly mixing and moving, but also extremely small in size, removing this debris is very difficult. We generally focus removal efforts on our shorelines and coastal areas, before debris has the chance to make it to the open ocean and before they have broken into microplastic pieces, which are inherently difficult to remove from the environment.

Hand holding small white plastic ball.

Since the garbage patches are primarily made up of very small microplastic debris that is constantly mixing throughout the water column, they definitely can’t be seen from space. (NOAA)

It possible to sail through a garbage patch without even realizing it! (NOAA)

However, preventing marine debris is the key to solving the problem. If you think about an overflowing sink, it’s obvious that the first step before cleaning up the water on the floor is to turn the faucet off—that’s prevention. By working to prevent marine debris through education and outreach, and each doing our part to reduce our contribution, we can stop this problem from growing.

Want to learn more about the garbage patches? Check out this blog post or visit the NOAA Marine Debris Program website where you can find more information as well as our Trash Talk video on the Great Pacific Garbage Patch.


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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.


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How Beach Cleanups Help Keep Microplastics out of the Garbage Patches

Basket full of faded, old plastic bottles on a beach.

Cleaning up a few plastic bottles on a beach can make a big difference when it comes to keeping microplastics from entering the ocean. (NOAA)

These days plastic seems to be everywhere; unfortunately, that includes many parts of the ocean, from the garbage patches to Arctic sea ice. With this pollution increasingly in the form of tiny plastic bits, picking up a few bottles left on the beach can feel far removed from the massive problem of miniscule plastics floating out at sea.

However, these two issues are more closely connected than you may think.

But how do we get from a large plastic water bottle, blown out of an overfilled trash can on a beach, to innumerable plastic pieces no bigger than a sesame seed—and known as microplastics—suspended a few inches below the ocean surface thousands of miles from land?

The answer starts with the sun and an understanding of how plastic deteriorates in the environment.

The Science of Creating Microplastics

Plastic starts breaking down, or degrading, when exposed to light and high temperatures from the sun. Ultraviolet B radiation (UVB), the same part of the light spectrum that can cause sunburns and skin cancer, starts this process for plastics.

This process, known as photo-oxidation, is a chemical reaction that uses oxygen to break the links in the molecular chains that make up plastic. It also happens much faster on land than in the comparatively cool waters of the ocean.

For example, a hot day at the beach can heat the sandy surface—and plastic trash sitting on it—up to 104 degrees Fahrenheit. The ocean, on the other hand, gets darker and colder the deeper you go, and the average temperatures at its surface in July can range from 45 degrees Fahrenheit near Adak Island, Alaska, to 89 degrees in Cannon Bay, Florida.

Back on that sunny, warm beach, a plastic water bottle starts to show the effects of photo-oxidation. Its surface becomes brittle and tiny cracks start forming. Those larger shards of plastic break apart into smaller and smaller pieces, but they keep roughly the same molecular structure, locked into hydrogen and carbon chains. A brisk wind or child playing on the beach may cause this brittle outer layer of plastic to crumble. The tide washes these now tiny plastics into the ocean.

Once in the ocean, the process of degrading slows down for the remains of this plastic bottle. It can sink below the water surface, where less light and heat penetrate and less oxygen is available. In addition, plastics can quickly become covered in a thin film of marine life, which further blocks light from reaching the plastic and breaking it down.

An Incredible Journey

Lots of tiny pieces of plastic covering rocks.

Microplastics, tiny bits of plastic measuring 5 millimeters or less, are often the result of larger pieces of plastic breaking down on land before making it into the ocean. They can also come from cosmetics and fleece clothing. (NOAA)

In general, plastic breaks down much, much more slowly in the ocean than on land. That means plastic objects that reach the ocean either directly from a boat (say trash or nets from a fishing vessel) or washed into the sea before much degradation has happened are much less likely to break into smaller pieces that become microplastics. This also applies to plastics that sink below the ocean surface into the water column or seafloor.

Instead, plastic that has spent time heating up and breaking down on land is most likely to produce the microplastics eventually accumulating in ocean gyres or garbage patches, a conclusion supported by the research of North Carolina State University professor Anthony Andrady and others.

Of course, microplastics in the form of “microbeads” in face wash and other cosmetics or microfibers in fleece clothing also can reach the ocean by slipping through waste water treatment systems.

However, regularly patrolling your favorite beach or waterway and cleaning up any plastic or other marine debris can go a long way to keeping millions of tiny microplastics—some so tiny they can only be seen with a microscope—from reaching the garbage patches and other areas of the ocean.

The great thing is anyone can do this and you don’t have to wait for the International Coastal Cleanup each September to get started.

Find more tips and resources to help you on your way:


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Taking a Closer Look at Marine Debris in Your Backyard

Here's hoping your backyard doesn't look like this: debris scattered on the ocean floor near the Pacific Islands. (NOAA)

Here’s hoping your backyard doesn’t look like this: debris scattered on the ocean floor near the Pacific Islands. (NOAA)

Check out NOAA’s Marine Debris Blog for their ongoing series, Marine Debris in Your Backyard, which examines the unique challenges of marine debris and its impacts on various parts of the United States.

Join them as they “journey across the nation, looking at the nine different regions the NOAA Marine Debris Program spans and the most common types of debris found in them, and how it may have ended up there.”

So far, they have visited the following places:

  • Alaska, where remote beaches, rough seas, and limited fair weather mean volunteers have only a few months each year to remove anywhere from one to 25 tons of debris per mile of shoreline.
  • Great Lakes, where 21 percent of the world’s surface fresh water resides, discarded fishing lines often entangle wildlife, and rumors of a plastic-filled “garbage patch” are beginning to appear.
  • Pacific Islands, where Hawaii, Guam, American Samoa, the Commonwealth of the Northern Mariana Islands, and a whole lot of open ocean make up the largest region NOAA supports, but where there is so little space for landfills that NOAA helped establish a public-private partnership in Hawaii to turn abandoned fishing gear into a local electricity source.
  • California, where its 1,100 miles of shoreline vary from coastal mountains in the north to well-populated, sandy beaches in the south, and where the nation’s first “Trash Policy” will attempt to control the flow of garbage in California’s waterways.

Stay tuned as they continue working their way around the shores of the United States, and ask yourself, what does marine debris look like where you live? How do you help keep it out of the ocean?

And remember, even if you live hundreds of miles from a beach, a piece of litter such as a cigarette butt (which actually contains plastic) or a plastic bag can still make its way through storm drains and rivers to the ocean. This makes marine debris, no matter where you live, truly everyone’s problem.


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Is There a Garbage Patch in the Great Lakes?

This is a post by Sarah Opfer, NOAA Marine Debris Program Great Lakes Regional Coordinator.

Plastic debris in the form of fragments, bottle caps, food packaging, and smoking products are commonly found on Great Lake beaches. Here, marine debris has washed up at Maumee Bay State Park on the shores of Lake Erie. (NOAA Marine Debris Program)

Plastic debris in the form of fragments, bottle caps, food packaging, and smoking products are commonly found on Great Lake beaches. Here, marine debris has washed up at Maumee Bay State Park on the shores of Lake Erie. (NOAA Marine Debris Program)

The “Great Pacific Garbage Patch“—a purported island of trash twice the size of Texas floating in the Pacific Ocean—receives a lot of media attention. Recent reports suggest that a similar garbage patch may be developing in the Great Lakes as well.

However, based on research we know that the name “garbage patch” is misleading and that there is no island of trash forming in the middle of the ocean. We also know that there is no blanket of marine trash that is visible using current satellite or aerial photography.

Plastic debris is found in Great Lake waters as well. This debris was pulled from a Lake Erie marina during a cleanup. (NOAA Marine Debris Program)

Plastic debris is found in Great Lake waters as well. This debris was pulled from a Lake Erie marina during a cleanup. (NOAA Marine Debris Program)

Yet, there are places in the ocean where currents bring together lots and lots of floatable materials, such as plastics and other trash. While the types of litter gathering in these areas can vary greatly, from derelict fishing nets to balloons, the kind that is capturing the most attention right now are microplastics. These are small bits of plastic often not immediately evident to the naked eye.

While we know about the so-called “garbage patches” in the Pacific Ocean, could there be a similar phenomenon in other parts of the world, including the Great Lakes? Recent research on the distribution of plastics in the Great Lakes has people now asking that very question.

The Great Lakes are no mere group of puddles. They contain nearly 20% of the world’s surface freshwater and have a coastline longer than the East Coast of the United States. Within the Great Lakes system, water flows from Lake Superior and Lake Michigan, the lakes furthest west and highest in elevation, east into Lake Huron. From there, it travels through Lake St. Clair and the Detroit River into Lake Erie. Then, some 6 million cubic feet of water pass over Niagara Falls each minute and into Lake Ontario before flowing through the St. Lawrence River and into the Atlantic Ocean.

Average summer water circulation patterns in the Great Lakes. Beletsky et al. 1999 (NOAA Great Lakes Environmental Research Laboratory)

Average summer water circulation patterns in the Great Lakes. Beletsky et al. 1999 (NOAA Great Lakes Environmental Research Laboratory)

This water flow influences circulation patterns within and between each of the lakes. Currents within the Great Lakes also are powered by wind, waves, energy from the sun, water density differences, the shape of the lakebed, and the shoreline. These circulation currents have the tendency to create aggregations of garbage and debris in certain areas, just like in the oceans. But, just as in the Pacific Ocean, this doesn’t mean the Great Lakes have floating trash islands either.

In an effort to better identify and understand how plastic debris is spread throughout the Great Lakes, researchers at the University of Waterloo in Canada have partnered with COM DEV on an exploratory research project. COM DEV is a designer and manufacturer of space and remote sensing technology. Researchers are working with this industry partner to develop and test the ability of different remote sensors to detect plastics in the Great Lakes.

If they find the task is feasible and the trial runs prove to be effective, this work could be applied beyond the Great Lakes and across the United States. The NOAA Marine Debris Program, part of the Office of Response and Restoration, is engaged with and following the project. We plan to participate in the next steps of this promising effort. You can learn more about the project and a related workshop on plastic pollution in the Great Lakes.

Sarah Opfer

Sarah Opfer

Sarah Opfer received her bachelor’s and master’s degrees in biology from Bowling Green State University and was a Knauss Sea Grant fellow with NOAA in 2009. She is based in Ohio and enjoys having Lake Erie in her back yard! While away from work she enjoys cooking, reading, kayaking, dreaming of places she wants to travel to, and spending time with her family.


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Where Are the Pacific Garbage Patches Located?

Microplastics in sand.

Microplastics, small plastics less than 5 millimeters long, are an increasingly common type of marine debris found in the water column (including the “garbage patches”) and on shorelines around the world. Based on research to date, most commonly used plastics do not fully degrade in the ocean and instead break down into smaller and smaller pieces. (NOAA Marine Debris Program)

The Pacific Ocean is massive. It’s the world’s largest and deepest ocean, and if you gathered up all of the Earth’s continents, these land masses would fit into the Pacific basin with a space the size of Africa to spare.

While the Pacific Ocean holds more than half of the planet’s free water, it also unfortunately holds a lot of the planet’s garbage (much of it plastic). But that trash isn’t spread evenly across the Pacific Ocean; a great deal of it ends up suspended in what are commonly referred to as “garbage patches.”

A combination of oceanic and atmospheric forces causes trash, free-floating sea life (for example, algae, plankton, and seaweed), and a variety of other things to collect in concentrations in certain parts of the ocean. In the Pacific Ocean, there are actually a few “Pacific garbage patches” of varying sizes as well as other locations where marine debris is known to accumulate.

The Eastern Pacific Garbage Patch (aka “Great Pacific Garbage Patch”)

In most cases when people talk about the “Great Pacific Garbage Patch,” they are referring to the Eastern Pacific garbage patch. This is located in a constantly moving and changing swirl of water roughly midway between Hawaii and California, in an atmospheric area known as the North Pacific Subtropical High.

NOAA National Weather Service meteorologist Ted Buehner describes the North Pacific High as involving “a broad area of sinking air resulting in higher atmospheric pressure, drier warmer temperatures and generally fair weather (as a result of the sinking air).”

This high pressure area remains in a semi-permanent state, affecting the movement of the ocean below. “Winds with high pressure tend to be light(er) and blow clockwise in the northern hemisphere out over the open ocean,” according to Buehner.

As a result, plastic and other debris floating at sea tend to get swept into the calm inner area of the North Pacific High, where the debris becomes trapped by oceanic and atmospheric forces and builds up at higher concentrations than surrounding waters. Over time, this has earned the area the nickname “garbage patch”—although the exact content, size, and location of the associated marine debris accumulations are still difficult to pin down.

Map of ocean currents, features, and areas of marine debris accumulation (including

This map is an oversimplification of ocean currents, features, and areas of marine debris accumulation (including “garbage patches”) in the Pacific Ocean. There are numerous factors that affect the location, size, and strength of all of these features throughout the year, including seasonality and El Nino/La Nina. (NOAA Marine Debris Program)

The Western Pacific Garbage Patch

On the opposite side of the Pacific Ocean, there is another so-called “garbage patch,” or area of marine debris buildup, off the southeast coast of Japan. This is the lesser known and studied, Western Pacific garbage patch. Southeast of the Kuroshio Extension (ocean current), researchers believe that this garbage patch is a small “recirculation gyre,” an area of clockwise-rotating water, much like an ocean eddy (Howell et al., 2012).

North Pacific Subtropical Convergence Zone

While not called a “garbage patch,” the North Pacific Subtropical Convergence Zone is another place in the Pacific Ocean where researchers have documented concentrations of marine debris. A combination of oceanic and atmospheric forces create this convergence zone, which is positioned north of the Hawaiian Islands but moves seasonally and dips even farther south toward Hawaii during El Niño years (Morishige et al., 2007, Pichel et al., 2007). The North Pacific Convergence Zone is an area where many open-water marine species live, feed, or migrate and where debris has been known to accumulate (Young et al. 2009). Hawaii’s islands and atolls end up catching a notable amount of marine debris as a result of this zone dipping southward closer to the archipelago (Donohue et al. 2001, Pichel et al., 2007).

But the Pacific Ocean isn’t the only ocean with marine debris troubles. Trash from humans is found in every ocean, from the Arctic (Bergmann and Klages, 2012) to the Antarctic (Eriksson et al., 2013), and similar oceanic processes form high-concentration areas where debris gathers in the Atlantic Ocean and elsewhere.

You can help keep trash from becoming marine debris by:

Carey Morishige, Pacific Islands regional coordinator for the NOAA Marine Debris Program, also contributed to this post.

Literature Cited

Bergmann, M. and M. Klages. 2012. Increase of litter at the Arctic deep-sea observatory HAUSGARTEN. Marine Pollution Bulletin, 64: 2734-2741.

Donohue, M.J., R.C. Boland, C.M. Sramek, and G.A Antonelis. 2001. Derelict fishing gear in the Northwestern Hawaiian Islands: diving surveys and debris removal in 1999 confirm threat to coral reef ecosystems. Marine Pollution Bulletin, 42 (12): 1301-1312.

Eriksson, C., H. Burton, S. Fitch, M. Schulz, and J. van den Hoff. 2013. Daily accumulation rates of marine debris on sub-Antarctic island beaches. Marine Pollution Bulletin, 66: 199-208.

Howell, E., S. Bograd, C. Morishige, M. Seki, and J. Polovina. 2012. On North Pacific circulation and associated marine debris concentration. Marine Pollution Bulletin, 65: 16-22.

Morishige, C., M. Donohue, E. Flint, C. Swenson, and C. Woolaway. 2007. Factors affecting marine debris deposition at French Frigate Shoals, Northwestern Hawaiian Islands Marine National Monument, 1990-2002. Marine Pollution Bulletin, 54: 1162-1169.

Pichel, W.G., J.H. Churnside, T.S. Veenstra, D.G. Foley, K.S. Friedman, R.E. Brainard, J.B. Nicoll, Q. Zheng and P. Clement-Colon. 2007. Marine debris collects within the North Pacific Subtropical Convergence Zone [PDF]. Marine Pollution Bulletin, 54: 1207-1211.

Young L. C., C. Vanderlip, D. C. Duffy, V. Afanasyev, and S. A. Shaffer. 2009. Bringing home the trash: do colony-based differences in foraging distribution lead to increased plastic ingestion in Laysan albatrosses? PLoS ONE 4 (10).


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How Much Would it Cost to Clean up the Pacific Garbage Patches?

This is a post by Carey Morishige, Pacific Islands Regional Coordinator for the NOAA Marine Debris Program.

Over the last several years, the infamous “Great Pacific Garbage Patch” has gained popularity. Whether described as an island of trash or a soup of plastic, it has haunted the dreams of ocean conservationists. As I described in my last post, there are a lot of misconceptions about the so-called garbage patch, among them the size and amount of marine debris entrained in this area.

To understand the many unknowns about the “garbage patch,” you must first understand what the area really is. In a nutshell, it is a large area of marine debris concentration caused by the clockwise movement of the surface of the ocean. Sailors and fishermen have known of this area for decades—to them it is the North Pacific Subtropical High, a high pressure zone typically avoided by sailors.

One of the common questions we receive is: Why can’t we go out and clean this area up? Sounds easy and simple—if only it was! There are many factors that must be taken into account, such as the fact that these areas of concentrated marine debris move and change throughout the year and many of these areas also have abundant sea life, much of which is microscopic.

Let’s crunch some quick and dirty numbers on the cost of a cleanup:

Suppose we were to attempt to clean up less than 1% of the North Pacific Ocean (a 3-degree swath between 30° and 35°N and 150° to 180°W), which would be approximately 1,000,000 km2. Assume we hired a boat with an 18 ft (5.5 m) beam and surveyed the area within 100 m off of each side of the ship.  If the ship traveled at 11 knots (20 km/hour), and surveyed during daylight hours (approximately 10 hours a day), it would take 67 ships one year to cover that area! At a cost of $5,000-20,000/day, it would cost between $122M and $489M for the year.  That’s a lot of money—and that’s only for boat time. It doesn’t include equipment or labor costs (keep in mind that not all debris items can be scooped up with a net).

Derelict fishing net floating in the open ocean.

Derelict fishing nets are frequently encountered marine debris items and cannot easily be scooped up with net. Credit: NOAA Fisheries Observer Program

The ultimate solution to the global problem of marine debris is not in clean up and removal (we can do that every day for the rest of our lives). The solution lies in prevention—stopping marine debris at the source; preventing trash from getting into our oceans and waterways in the first place!

For more information on the garbage patch and ways that you can help prevent marine debris, check out the NOAA Marine Debris Program website.

This originally was posted on the NOAA Marine Debris Blog.