NOAA's Response and Restoration Blog

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


10 Comments

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).


1 Comment

Japan Confirms Dock on Washington Coast Is Tsunami Marine Debris

A worker uses a 30% bleach spray to decontaminate the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012.

January 3, 2013 — A worker uses a 30% bleach spray to decontaminate and reduce the spread of possible marine invasive species on the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012. (Washington Department of Fish and Wildlife/Allen Pleus)

The Japanese Consulate has confirmed that a 65-foot, concrete-and-foam dock that washed ashore in Washington’s Olympic National Park in late December 2012 is in fact one of three* docks from the fishing port of Misawa, Japan. These docks were swept out to sea during the earthquake and tsunami off of Japan in March 2011, and this is the second dock to be located. The first dock appeared on Agate Beach near Newport, Ore., in June 2012.

Using our trajectory forecast model, NOAA’s Office of Response and Restoration helped predict the approximate location of the dock after an initial sighting reported it to be floating somewhere off of Washington’s Olympic Peninsula. When the dock finally came aground, it ended up both inside the bounds of NOAA’s Olympic Coast National Marine Sanctuary and a designated wilderness portion of Olympic National Park.

Japanese tsunami dock located on beach within Olympic National Park and National Marine Sanctuary.

In order to minimize damage to the coastline and marine habitat, federal agencies are moving forward with plans to remove the dock. In addition to being located within a designated wilderness portion of Olympic National Park, the dock is also within NOAA’s Olympic Coast National Marine Sanctuary and adjacent to the Washington Islands National Wildlife Refuge Complex. (National Park Service)

According to the Washington State Department of Ecology, representatives from Olympic National Park, Washington State Department of Fish and Wildlife, and Washington Sea Grant Program have ventured out to the dock by land several times to examine, take samples, and clean the large structure.

Initial results from laboratory testing have identified 30-50 plant and animal species on the dock that are native to Japan but not the United States, including species of algae, seaweed, mussels, and barnacles.

In addition to scraping more than 400 pounds of organic material from the dock, the team washed its heavy side bumpers and the entire exterior structure with a diluted bleach solution to further decontaminate it, a method approved by the National Park Service and Olympic Coast National Marine Sanctuary.

Government representatives are examining possible options for removing the 185-ton dock from this remote and ecologically diverse coastal area.

Look for more information and updates on Japan tsunami marine debris at http://marinedebris.noaa.gov/tsunamidebris/.

*[UPDATE 4/5/2013: This story originally stated that four docks were missing from Misawa, Japan and that “the first dock was recovered shortly afterward on a nearby Japanese island.” We now know only three docks were swept from Misawa in the 2011 tsunami and none of them were found on a Japanese island. This dock has now been removed from the Washington coast.]