A large occurrencee occurrance of the dead zones is natural, the Sargasso Sea was a well known feature long before man regularly crossed the Atlantic. It is now that we are just throwing so much junk into the seas that this is more visible, so visable and so irritating. It is mostly greed, the cheap buck for disposal, like the pigs dumped into the river in China, so 12,000 pigs, really, really disgusting. In my 64 years, greed is the usual motive, follow the money, it has never been moreso, and afterall, the PTB seem to have many among them who do not see themselves living into a future World, so what do they care.