Coastal Dead Zones
By admin - July 29, 2010
More and more dead zones are plaguing the World. Although, these dead zones are not horrendous. These zones are such areas of coastal water bodies that are deprived of oxygen. Hence, most of the aquatic life has ceased to exist in such areas. Read on to know more about these coastal dead zones.
A prime example is the Gulf of Mexico which experiences a dead zone every summer. At this time, this area is bereft of any aquatic life including fishes. This dead zone is expanding over the years and now spans nearly 21,000 square kilometers. Another example is the Chesapeake bay. From the 70s, a formation of dead zone is an yearly event. This effects nearly 40% of the bay on some occasions.
Locations of Coastal Dead Zones
Around the World, around 146 dead zones are present. These are the such areas which has a low dissolved oxygen to sustain the aquatic life. Every decade, the dead zones have doubled. Most of them are seasonal but a few are present through out the year.
The dead zones can range from a small section of estuaries and coastal bays to large ocean beds. These can span nearly 70, 000 square kilometers. Several of these dead zones occur in the temperate waters, which are located in the seas of Europe and off the east coast of the U.S. A few of the dead zones have been found off the coasts of New Zealand, Australia, Brazil, Japan, and China.
The world’s largest dead zone is present in the Baltic Sea. This is due to the over-fertilization of the sea by several factors such as human waste discharge, nitrogen deposition from burning fossil fuels and agricultural runoff.
Coastal Dead Zones in the U.S.
43% of the known dead zones of the world are present in the US coastal regions. The world’s 2nd largest dead zone is the Gulf of Mexico. This severely disrupts the productivity of fishery which provides nearly 18% of the annual US catch.
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