The Dead Zone 


Areas of depleting oxygen levels in our Oceans.

Dead Zone Lesson Plan (requires adobe reader)

Assignment Earth: Dead Zone (video clip)

Dead Zones? 

Dead Zones are hypoxic areas in the world's ocean or possibly other large bodies of water. In March 2004, it was reported in the GEO Year Book 2003 that there were 146 known dead zones in the world's oceans that could not support marine life because of depleted oxygen levels. The largest known dead zone covered 70,000 square kilometers.

Dead Zone Causes?

Dead Zones can be caused by eutrophication, which eventually leads to hypoxia or oxygen depletion. In this cause, oxygen depletion is due to excessive plant growth.  Hypoxia is the most common cause for the dead zone.  Hypoxia or oxygen depletion can be caused by a number of factors including natural ones, but it is most commonly caused by pollution.

Dead Zone Solutions?

To combat Hypoxia, we need to decrease the amount of land-derived nutrients from reaching rivers.  This can be done by improving the sewage system and by reducing the amount of fertilizers leaching into the rivers.

 

Useful Vocabulary

Hypoxia: a  phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point detrimental to aquatic organisms living in the system

Eutrophication: an increase in chemical nutrients in an ecosystem.