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| Earth on Sep 13, 2010

Kara Lavender Law: Ocean garbage patch in Atlantic, too

Scientists have discovered another ocean region swirling with plastic debris – like the notorious North Pacific Garbage Patch. But this one’s in the Atlantic.

Scientists have discovered another ocean region swirling with plastic debris – like the notorious North Pacific Garbage Patch – but this one’s in the Atlantic. Oceanographer Kara Lavender Law of the Sea Education Association is lead author of the August 2010 report. She said high concentrations of tiny, broken-down pieces of plastic have accumulated in a region of mixing ocean currents.

Kara Lavender Law: The vast majority of the debris is very, very small. But you certainly see recognizable items from the deck of the ship. You see bottles, toothbrushes, fishing gear. It’s fairly shocking to see these common household items floating thousands of miles from shore.

The ocean region stretches about from the latitude of Cuba up to the latitude of Virginia. But, she said, the true extent of the Atlantic garbage patch is still unknown.

Kara Lavender Law: In most parts of the ocean, you see very little to zero plastic floating. These regions are special because of the currents that carry the floating plastic debris and other debris to those particular regions.

Law said that, back in the 1970’s, research ships towing the ocean surface for plankton began to pull up tiny fragments of plastic in their nets. She said that scientists can’t figure out why there isn’t more plastic in the ocean today. She said that the levels of plastic they’ve found over the past two decades are pretty consistent, while the amount of plastic produced and disposed of has increased.

Kara Lavender Law: We looked at how the amount of plastic in that accumulation zone changes over time. Surprisingly, we found that the concentration of plastic seems to remain steady in the region, and at this point it’s not exactly clear what is happening to the plastic.

She said because it’s likely impossible to measure how much plastic is going into the oceans, it’s hard to be exact about how much plastic “should” be in the Atlantic.

Kara Lavender Law: We looked at records of global plastic production as well disposal in the waste stream of the U.S., and both of those trends are strongly increasing over our study period. So we infer that the input of trash in ocean has also increased. If you assume that and then see that we’re not observing an increase that’s quite surprising, and raises a lot of questions about where this trash that presumably enters the oceans is going.

Law explained a number of theories.

Kara Lavender Law: One, we know that are only measuring plastic larger than a third of a millimeter in size – that’s the size of the mesh we use to collect them. It’s entirely possible that plastics, over time, are breaking down into pieces small enough that they pass through the net.

She said marine organisms could be eating the plastic, or biological growth on plastic could make the pieces heavy enough to sink beyond the range of the net tows. The plastic could also be washing up on beaches. Law said that the only way to truly decrease the amount of plastic in the Atlantic is to stop it from entering the ocean in the first place – by recycling it properly.