Scientists alarmed by ocean dead-zone growth Dead zones where fish and most marine life can no longer survive are spreading across the continental shelves of the world's oceans at an alarming rate as oxygen vanishes from coastal waters, scientists reported Thursday. The scientists place the problem on runoff of chemical fertilizers in rivers and fallout from burning fossil fuels, and they estimate there are now more than 400 dead zones along 95,000 square miles of the seas - an area more than half the size of California. The number of those areas has nearly doubled every decade since the 1960s, said Robert J. Diaz, a biological oceanographer at the Virginia Institute of Marine Science. "Dead zones were once rare, but now they're commonplace, and there are more of them in more places," he said....