Mongabay: If carbon dioxide levels continue to rise as expected, marine dead zones in the tropics are expected to increase by 50 percent in just over four decades, according to a new study from the Leibniz Institute of Marine Sciences in Germany. The expansion of marine dead zones in tropical seas could have devastating impacts on ocean ecosystems and fisheries. Hundreds of meters below the surface tropical oceans contain low amounts of oxygen, resulting in what scientists call ‘dead zones’ due …