Environment & Energy
Related: About this forumThat "Missing" Ocean Plastic? How About In Fish - That Is To Say, In Us, Eventually
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To figure out how much refuse is floating in those garbage patches, four ships of the Malaspina expedition, a global research project studying the oceans, fished for plastic across all five major ocean gyres in 2010 and 2011. After months of trailing fine mesh nets around the world, the vessels came up lightby a lot. Instead of the millions of tons scientists had expected, the researchers calculated the global load of ocean plastic to be about only 40,000 tons at the most, the researchers report online today in the Proceedings of the National Academy of Sciences. We cant account for 99% of the plastic that we have in the ocean, says Duarte, the teams leader.
He suspects that a lot of the missing plastic has been eaten by marine animals. When plastic is floating out on the open ocean, waves and radiation from the sun can fragment it into smaller and smaller particles, until it gets so small it begins to look like fish foodespecially to small lanternfish, a widespread small marine fish known to ingest plastic. Yes, animals are eating it, says oceanographer Peter Davison of the Farallon Institute for Advanced Ecosystem Research in Petaluma, California, who was not involved in the study. That much is indisputable. But, he says, its hard to know at this time what the biological consequences are. Toxic ocean pollutants like DDT, PCBs, or mercury cling to the surface of plastics, causing them to suck up all the pollutants in the water and concentrate them. When animals eat the plastic, that poison could be going into the fish and traveling up the food chain to market species like tuna or swordfish. Or, Davison says, toxins in the fish may dissolve back into the water
or for all we know theyre puking [the plastic] or pooping it out, and theres no long-term damage. We dont know.
Its impossible to know how much the animals are eating, says Kara Law, a physical oceanographer at the Sea Education Association in Woods Hole, Massachusetts, who was not involved in the work. The estimated amount of plastic entering the ocean that the study uses is almost half a century old, and were desperately in need of a better estimate of how much plastic is entering the ocean annually.
Whats more, both Davison and Law say there are a number of other potential places the plastic could be ending up. It could be washing ashore, and a lot of it could be degrading into pieces too small to be detected. Another possibility is that organisms sticking to and growing on the plastic are dragging the junk beneath the oceans surface, either suspending it in the water column or sinking it all the way to the sea floor. Microbes may even be eating the stuff.
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http://news.sciencemag.org/environment/2014/06/ninety-nine-percent-oceans-plastic-missing
defacto7
(13,485 posts)It's there.