This is not the title of a sequel to a Stephen King novel. “Dead zones” in this context are areas where the bottom water (the water at the sea floor) is anoxic - meaning that it has very low (or completely zero) concentrations of dissolved oxygen. These dead zones are occurring in many areas along the coasts of major continents, and they are spreading over larger areas of the sea floor. Because very few organisms can tolerate the lack of oxygen in these areas, they can destroy the habitat in which numerous organisms make their home.
[quote]BigRagoo wrote:
There’s been a dead zone in the gulf for some years now that grows and shrinks according to the heat and amount of river wash dumped into it.[/quote]
It’s bad. The only possible solution I have heard of is to start 100% organic farming up the banks of the Mississippi. Apparently it’s all of the fertilizer run-off that causes it.
[quote]beebuddy wrote:
BigRagoo wrote:
There’s been a dead zone in the gulf for some years now that grows and shrinks according to the heat and amount of river wash dumped into it.
It’s bad. The only possible solution I have heard of is to start 100% organic farming up the banks of the Mississippi. Apparently it’s all of the fertilizer run-off that causes it.[/quote]
Correct. The fertilizers are nutrients to the phytoplankton, which then grow and mulitply faster, whose wastes are nutrients to bacteria on the floor which uses the same oxygen that other biota need to survive. These bacteria use the dissolved oxygen at an accelerated rate when the phytoplankton are booming, and thus, create areas of low to no dissolved oxygen.