National Geographic: The world’s hypoxic zones–swaths of ocean too oxygen-deprived to support fish and other marine organisms–are rapidly expanding as sea temperatures rise, a new study suggests. Researchers have tracked a decline in dissolved oxygen levels since 1960 in the tropical Pacific and Atlantic Oceans, which has extended the size of these undersea deserts and intensified their effects. The oxygen level in these zones "is below the critical oxygen level for fish and other large marine …