Dead Zones in Oceans
Table of contents for National Ocean Week
- Dead Zones in Oceans
- Dolphin Rescues Whales
There are zones in the Ocean that are dead due to lack of oxygen. These spots are due to a condition called Hypoxia. Hypoxia or Anoxic areas of the ocean mean that there are very low or non existent oxygen levels on the Ocean Floor. Because of this life cannot live and the area or zone is considered dead.
Is this something to be worried about? The answer is not that clear.
Anoxic areas occur very naturally throughout the world. The one most prevalent in the United states is off the coast of New Jersey and in the Gulf at the mouth of the Mississippi river. The naturally occurring zones occur due to nutrient rich warm river waters that flow over deeper colder Ocean waters. This causes algal and micro bacteria growth on the upper levels. The growth blocks sunlight and reduces oxygen levels on the bottom layer. Living organisms either escape or die out causing decay. The bacteria from the decay use up the oxygen and give off a lot of carbon monoxide. It is actually a very simple process.
So why the concern over a naturally occurring thing? These areas are beginning to grow and shift. The growth may be due to nutrients that are not natural.
A big concern is with farmers pesticides and fertilizers. The excess runs off into watersheds and eventually rivers (see Your Effects on the Ocean ). This extra supply of non-natural material can grow a dead zone and even shift a dead zone.
Since these dead zones occur near shorelines a small shift can begin to effect coal reefs. Coral reefs are known as the oceans nurseries. These are the breeding grounds for many ocean animals and they also feed much of the ocean population. They are very important to the health of our planet.
So what can you do? You can support organic farms and farmers. You do this by buying their goods. The more in demand organic food is, the more farmers will farm without the use of pesticides and extra fertilizer. There have been recent studies that show that pesticides and fertilizer is becoming less effective as the plants and pests have become nearly immune to the effects (more on this at a later date).
Sources for more information
Creeping Dead Zones (http://daac.gsfc.nasa.gov/oceancolor/scifocus/oceanColor/dead_zones.shtml)
Hypoxia in the Gulf of Mexico (http://toxics.usgs.gov/hypoxia/hypoxic_zone.html)
What is Hypoxia (great graphic here) (http://www.epa.gov/msbasin/taskforce/hypoxia.htm)
