It has become quite common to say that we are living through a mass extinction—a period in which human activity has multiplied the rate at which species are disappearing from the earth by a factor perhaps as large as a thousand. It is probably also fair to call this an era marked by what is called ocean anoxification. Over the past fifty years, the amount of ocean water with no oxygen at all has quadrupled globally, giving us a total of more than four hundred “dead zones”; oxygen-deprived zones have grown by several million square kilometers, roughly the size of all of Europe; and hundreds of
...more
