字幕表 動画を再生する 英語字幕をプリント So in today's consumer society, the production of plastics has sky-rocketed and although most of it gets into landfills or it gets recycled, still a lot of it gets into the ocean accidentally, flowing from beaches or rivers or ships, and that plastic will stay in the ocean for quite a long time. It's hard to measure in really weight how much plastics there is. What we do know is that in some regions of the north pacific, there's more weight in plastic than what there is in life. There's more if you go out fishing, you find more plastics in your nets than you do fish or even plankton. We've been trying to investigate how long the plastic will be in the ocean and how it gets from the coast actually into what we call, "The Great Ocean Garbage Patches". So what we used is surface drifter buoys. Surface drifter buoys are in the ocean and they behave just like plastic, they float around. But unlike the plastics, they have a GPS sensor so we know at all times where they are and we use the paths of these surface drifter buoys to get a statistical feeling for how garbage moves around in the ocean. Using these statistics, we could project the paths of all the plastics in all of the ocean for the next thousand years. The garbage starts, it goes around the ocean and where the people live and within a few months the currents move them into the open ocean and there they form the great garbage patches which are kind of like vaccuum cleaners of the ocean. There are six of them. There's five in each of the subtropical oceans between the continents, and then there's a sixth all the way up in the Arctic in the Bering Sea. There are patches that go away a little bit with time due to the seasonal shifts of the winds but in general, these patches stay there for a very long time. Within garbage patches, it's not beach balls or rubber duckies or big things floating around there. Some of it is, but most of it is actually really small, millimetre-sized plastic pellets. The sun degrades the plastics over time and the plastic just disintegrates into smaller and smaller pellets that just float in the upper ocean and makes this kind of soup structure. Plankton grow on the pellets, birds eat them, fish eat them, and because these pellets and the plastic can contain quite a lot of toxins, that becomes part of the food chain. What exact effect the plastic has on the ecosystem we don't really know yet. Even if we prevent and stop tomorrow, these plastic patches are not going away. The garbage patches will stay there for at least the next thousand years. There's really no solution for getting the plastics out of the ocean. It's too small, it's too diverse, it's too thin, the soup, to get out there with a ship and pick it up. Of course, the way to go then would be to make plastics that do break down, plastics that even if they get into the ocean, don't really have the time to accumulate in these garbage patches because they will just disintegrate and will be gone from the food chain. What we found is that the patches are really an international problem. It's not that plastic from one country ends up in one particular patch, quite the contrary, all of the patch…all of the plastics ends up in all of the patches and the patches are inter-connected in a way that we didn't know before. All of the rubbish in one patch can actually move on timescales of ten years or so into the other patches so if we want to prevent, reduce or clean up the patches, we really need to have an international collaboration on that.