Oceans, Rivers and Dead Zones

The term dead zone has been tossed around quite a bit in the scientific literature lately, especially to refer to nonviable water bodies, but what exactly is a “dead zone”, what are the causes behind this massive ecosystem loss in our oceans? Dead zones are bodies of water with highly reduced levels of oxygen dissolved in the water. This decrease in oxygen level is caused by the seasonal overgrowth of algal blooms that then decomposes in the water. The decomposition process consumes oxygen and depletes the oxygen supply available to healthy marine life: fishes and other aquatic life forms migrate or die. This phenomenon has been linked to fertilizers run offs from farmlands as well as the dumping of sewage water into oceans and rivers. To date, scientists have identified more than 415 dead zones worldwide and this number has been doubling every decade. These dead zones are affecting our most prized fishing areas: the coastlines. Indeed, dead zones are driving out millions of fishermen and fisherwomen further out to sea to fish which not only increases the fuel used on boats which drives higher oceanic pollution but also drives up the costs of the industry itself, leading to a decease in fishing jobs.


As a society, we need to find innovative and earth friendly methods for a more efficient and effective use of fertilizers on our farmland as well as intervene to promote better soil management on croplands. Next week:an uplifting environmental special news story.

 Photo by Aaron Buren

Photo by Aaron Buren

Anna Chahuneau