Pacific garbage patch may be 16 times bigger than thought | Science News for Students

Pacific garbage patch may be 16 times bigger than thought

Fishing nets and ropes make up roughly half of the debris
Apr 30, 2018 — 6:45 am EST
beach garbage

Fishing nets and ropes make up nearly half of the mass of plastic in the Pacific Ocean’s notorious garbage patch, a new study suggests.

NOAA Coral Reef Ecosystem Program/Flickr (CC BY 2.0)

We’re going to need a bigger trash can.

There is a pooling of plastic waste that floats in the ocean between California and Hawaii. It’s known as the “great Pacific garbage patch.” This garbage patch spreads over 1.6 million square kilometers (600,000 square miles), a new study finds. And it contains at least 79,000 tons of material. That’s the equivalent to the mass of more than 6,500 school buses. The new numbers mean the hoard is four to 16 times as massive as past estimates had suggested.

Its name might imply a huge floating island of junk. This garbage patch is something else. It’s an area of the ocean where pieces of plastic can be found in high concentration. About 1.8 trillion plastic pieces make up the great Pacific garbage patch, scientists estimate. About 94 percent of the pieces are microplastics. These are particles smaller than half a centimeter (0.2 inch). Because they are so tiny, they make up only 8 percent of the overall mass. Large pieces, 5 to 50 centimeters (2 to 20 inches), account for 25 percent of the mass. Extra-large bits, those bigger than 50 centimeters (20 inches), make up the most of the mass: 53 percent.

Story continues below graph.

garbage graph
In the new study, researchers sorted plastic particles by size and type. These included pieces of hard plastics and thin sheets, nets and ropes and other forms like foam. Based on new estimates, the plastic mass mostly comes from very large particles bigger than 50 centimeters (20 inches). The bulk of those particles are fishing nets and ropes.
L. Lebreton et al/Scientific Reports 2018

Humans’ ocean activities, such as fishing and shipping, shed much of this plastic, the researchers found. Discarded fishing nets, for example, make up almost half of the garbage patch’s mass. A lot of that litter contains especially durable types of plastic. These include polyethylene (PAA-lee-ETH-uh-leen) and polypropylene (PAA-lee-PRO-pu-leen). Such plastics are designed to survive in aquatic environments.

Laurent Lebreton is an oceanographer with Ocean Cleanup. That’s a nonprofit foundation in Delft, the Netherlands. To get the new size and mass estimates, Lebreton and his colleagues collected plastic samples from the ocean surface and took images from above. They also used a computer to model particle pathways based on ocean circulation patterns and what’s known about where the plastic entered the ocean. The team published its findings March 22 in Scientific Reports.

Aerial photos provided the best tallies of the larger plastic pieces, the researchers note. That might explain why the new estimates are so much higher. Those older ones had relied on images taken from boats and data on ocean trawling — in addition to estimates from computer models.

But there’s also another potential explanation: The patch could have grown. It may have received a hue increase of debris from the 2011 tsunami that hit Japan and washed trash out to sea.

Power Words

(for more about Power Words, click here)

aerial     Of or taking place in the air.

colleague     Someone who works with another; a co-worker or team member.

computer     A program that runs on a computer that creates a model, or simulation, of a real-world feature, phenomenon or event.

concentration     (in chemistry) A measurement of how much of one substance has been dissolved into another.

debris     Scattered fragments, typically of trash or of something that has been destroyed. Space debris, for instance, includes the wreckage of defunct satellites and spacecraft.

environment     The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of components in some electronics system or product).

litter     Material that lies around in the open, having been discarded or left to fall where it may.

marine     Having to do with the ocean world or environment.

mass     A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.

microplastic     A small piece of plastic, 5 millimeters (0.2 inch) or smaller in size. Microplastics may have been produced at that small size, or their size may be the result of the breakdown of water bottles, plastic bags or other things that started out larger .

oceanography     (adj. oceanographic ) The branch of science that deals with the physical and biological properties and phenomena of the oceans. People who work in this field are known as oceanographers.

Pacific     The largest of the world’s five oceans. It separates Asia and Australia to the west from North and South America to the east.

particle     A minute amount of something.

plastic     Any of a series of materials that are easily deformable; or synthetic materials that have been made from polymers (long strings of some building-block molecule) that tend to be lightweight, inexpensive and resistant to degradation.

polyethylene     A plastic made from chemicals that have been refined (produced from) crude oil and/or natural gas. The most common plastic in the world, it is flexible and tough. It also can resist radiation.

polypropylene     The second most common plastic in the world. It is tough and durable. Polypropylene is used in packaging, clothing and furniture (such as plastic chairs).

sea     An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.

trillion     A number representing a million million — or 1,000,000,000,000 — of something.

tsunami     One or many long, high sea waves caused by an earthquake, submarine landslide or other disturbance.

waste     Any materials that are left over from biological or other systems that have no value, so they can be disposed of as trash or recycled for some new use.

Citation

Journal:​ ​​ L. Lebreton et al. Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic. Scientific Reports. Vol. 8, March 22, 2018. doi: 10.1038/s41598-018-22939-w.