A trashy map of Earth’s oceans Here’s an odd question…where does one ocean end an
A trashy map of Earth’s oceansHere’s an odd question…where does one ocean end and another begin? If you travel East from the Indian Ocean, you’ll eventually reach the Pacific, but when? Can you draw a line on a map? Not exactly the easiest thing is it? Cartographers could probably agree on a line but that’s just a convention.To answer that question, scientists from the University of New South Wales did something interesting. They tracked trash.The Earth’s oceans each have dominant currents that spin in circles around the basins known as gyres. They are driven by a combination of strong winds, upwelling, and weather patterns. Water in one of these gyres, and anything it is carrying, will tend to stay in that gyre for a while.In other words, water in some area is going to technically “be” in one of the oceans, or at least coming on a current directly from one ocean to another. These currents create natural dividing lines in the ocean that can be mapped; where these currents intersect, water on one side will go one way, water on the other side will tend to go the other way.Water isn’t easy to track because one particle of water looks a lot like the one next to it, but solid particles can be tracked. There is so much trash in the world’s oceans that tracking the trash allows for tracking of the water flowing around it.That’s the source of this map. This is a map the boundary of Earth’s oceans defined by water flow patterns. It’s not exactly where you’d put the dividing line between the Pacific and Indian Oceans if you were drawing a line yourself, but that’s how the currents are divided. Water from the South Pacific travels all the way to Africa. Circulation from the Atlantic wraps all the way around both Africa and South America. And finally, at the southern tip of the planet sits a nearly isolated current - the Antarctic circum-polar current.-JBBOriginal paper:http://scitation.aip.org/content/aip/journal/chaos/24/3/10.1063/1.4892530Read more:http://www.scientificamerican.com/podcast/episode/sea-garbage-shows-ocean-boundaries/ -- source link
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