Hypoxia (Oceanic Dead Zones)Posted 8 years ago under Uncategorized
All over the world are large areas just off the coast where the ocean is nearly dead.
The waters are hypoxic or devoid of oxygen. Fully oxygenated water has a concentration of ten parts per million of oxygen. Water that contains less than concentrations of oxygen lower than two parts per million are considered hypoxic. Marine animals either leave or die, due to the lack of oxygen. (1)
Rain flushes fertilizer from conventional farmer’s fields to streams and rivers. Ultimately these nitrogen and phosphorous fertilizers combine with a variety of other pollutants-industrial waste, fossil fuel emissions, urban runoff, and sewage combine to add higher amounts of nitrogen and phosphorous to the sea waters off the coast.
Conventional farming utilizes phosphorous and nitrogen chemical fertilizers. When rain and runoff carry these fertilizers into the ocean, marine life is suffocated. The fertilizers trigger overgrowth of marine plankton. Once the masses of plankton die, their death feeds ocean bacteria. The bacteria consume oxygen, and with an unnatural overabundance of plankton, the bacteria consume just about all of the oxygen left in the ocean. Shrimp, fish, and all other forms of marine life either leave the area or die from lack of oxygen. The end result is hypoxia, oceanic dead zones. These areas are devoid of nearly all life other than plankton and bacteria.
Scientists have documented coastal dead zones, areas that are hypoxic in over 400 coastal areas. All over the world, these dead zones are found downstream of conventional farming from Chesapeake Bay to Oregon to Denmark, and to the Black Sea. (2)
The ocean provides us with billions of dollars worth of food annually. Nothing of commercial importance survives a dead zone, fish, shellfish, and shrimp all either leave the area or suffocate in the dead waters. Many of these dead zones are thousands of square miles. The dead zone off of the Gulf of Mexico was once recorded as being an area larger than the state of New Jersey, 22,000 kilometers.
(2) Environment The Science Behind the Stories by Jay Withgott and Scott Brennan