What are Ocean Dead Zones:
Commonly refered to as hypoxic water, dead zones are areas of water that are lacking of oxygen making it imposible for marine wildlife to servive (10).
Causes:
The main cause of ocean dead zones is cultural eutrophication, which is the increased runoff of nutrients (such as nitrogen and phosphorous) due to human activity, which ends up in the hydrologic cycle. With increased intensive farming methods, relying on large amounts of fertilizers, and large scale animal farming, creating large amounts of manure, nutrient runoff into our water system is largely increasing.
Industrial processes and vehicle emissions also contribute to dead zones by releasing nitrogen into the air which eventually goes into water sources.
Sewage is another contributing factor to the increase of ocean dead zones. Ocean dead zones are also partially caused by natural factors adding nutrients into the water such as volcanic eruptions (10). However, since the industrial and agricultural revolution, nitrogen emissions have doubled and phosphorous emissions tripled. We have seen a similar spike in the number dead zones.
In developed countries the primary causes of ocean dead zones are animal manure, chemical fertilizers, and irrigation caused runoff. In developing countries it is mainly caused by untreated sewage, and industries that have no to little pollutant control (9).
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