Marine “Dead Zones” Will Increase, Scientists Predict
So-called “dead zones”–patches of ocean lacking aerobic (oxygen breathing) life–will most likely increase due to a rise in carbon dioxide (CO2) concentrations.
Because of CO2 build up in the atmosphere, its level of concentration in the oceans also increases. There, some of the CO2 converts to a simple acid called carbonic acid. (H2CO3).
What is becoming a much-studied phenomenon in recent years, these dead zones of depleted oxygen (02) - typically found at depths between 300 and 600 meters–are the result of several factors working separately and in combination: lower sea surface 02 levels, less heat exchanging (”ventilation”) with mid-level ocean depths due to over-all warming, and “euthrophication events” (an over-growth of a species due to excess nutrients).
It looks like ethanol subsidies may impede efforts to reduce the size of the Dead Zone in the Gulf of Mexico. A draft report from the EPA Science Advisory Board says that ethanol subsidies could lead to a dramatic increase in nutrient loading in the Mississippi river basin, due to diverting cropland to corn production.
