How the melting Arctic could spread invasive species far and wide
http://grist.org/news/how-the-melting-arctic-could-spread-invasive-species-far-and-wide/
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After 300 years of fruitless (and sometimes deadly) attempts to find the fabled Northwest Passage, a sea route to connect the Atlantic and Pacific oceans via the Arctic, global warmings shown up all those hard-man sailors by suddenly making the journey easy. In 2007, higher temperatures had melted enough of that pesky Arctic ice to open the passage up to non-icebreaking vessels for the very first time, and since then the ice has only continued to melt meaning more and more shippers will be using this efficient trade route.
But whats good news for shippers is not necessarily good news for the rest of us: More vessels taking the northern course is also projected to spread harmful invasive species.
Whats happening now is that ships move between oceans by going through the Panama or Suez [canals], but that means ships from higher latitudes have to divert south into tropical and subtropical waters, says Whitman Miller, who recently wrote about the issue in a commentary in the journal Nature Climate Change. [S]o if you are a cold water species youre not likely to do well in those warm waters. And, since freshwater flows through the Panama Canal, critters that cling on to hulls often die from osmotic shock as they go from saltwater to freshwater and back again.
But as more ships take a northerly route, the barnacles, mussels and crabs that hitch along for the journey wont be exposed to those shocks, and so will be more likely to survive the ride.
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The Northwest Passage