Reuters: A tidal wave of man-made trash is threatening world oceans, damaging wildlife, tourism and seafood industries and piling additional stress on seas already hit by climate change, conservationists said on Tuesday. A report by U.S.-based Ocean Conservancy detailed what it called a “global snapshot of marine debris” based on itemized records of rubbish collected by nearly 400,000 volunteers in 104 countries and places in a single day in September 2008. Close to 7 million pounds …