Wednesday, March 10, 2010

Dead Zones: Can You Hear Them Now?

Dead Zones, they are not just the scary cell phone commercials you see on T.V, they are the horrifying threat to our marine ecosystems. Dead zones are located in coastal areas where the oxygen concentrations are too low to sustain marine life. Dead zones are caused by excess nutrients, mainly phosphorous and nitrogen, seeping into the water system. These nutrients then fertilize algae blooms throughout the coast. After plants (microscopic plants) die and sink to the bottom, bacteria are fed. Bacteria consume the oxygen in the water which does not allow for fish and other bottom dwelling organisms to survive. Dead zones can be seasonal, usually appearing in the spring and fall, but can last year round if the nutrient levels stay high.

Throughout the world there are more than 400 dead zones today, compared to the 162 dead zones in the 1980's. The largest of these is the Baltic Sea. In National Gepgraphic's Daily News, the article starts out with the worry in the disappearance of the white-tailed eagle. The white-tailed eagle is a main focus for tourist attraction and is greatly affected by the algae blooms. Another species that is affected by algae blooms is the Baltic cod. The Baltic cod, however, has the effect on the sea's well being. The Baltic cod feeds on an organism that in turn, somewhere down the line eats algae. Overfishing is another problem that lessens the numbers of cod, which in turn increases the amount of algae.

Algae blooms are a huge problem. They affect the diversity and the sustainability of the coastal waters. Mainly, nutrients have the biggest impact on creating rapidly expanding blooms. These nutrients are from fertilizers and sewage, which are mainly human produced. Other factors increasing algae blooms are things like overfishing. Even though algae blooms, dead zones, have a major impact on the coastal marine life, other parts of the environment are affected. Surrounding food chains, such as the white-tailed eagle, are effected. Overall, dead zones are a huge problem that may not be able to be reversed and should be taken seriously since they cause a variety of environmental issues.

Websites and Pictures:

Posted by Amanda Hostetter (7)


  1. Seems like the Baltic has a gloomy-green future. Hopefully something can be done to reverse the process or even stop it from increasing. It doesn't help that it houses both marine and freshwater fish because of its brackish water. The article said that it has 7 out of the 10 larger dead zones, so where are the other three? I think there is one at the mouth of the Mississippi in the Gulf of Mexico but I don't know where the others are. Sadly most of our past efforts here in the US haven't made much progress solving the problem.

    Posted by Daniel Solomon

  2. Hopefully something can be done by the human population to reverse what is happening. However, knowing that organisms have a potential at adapting to their environment, do you think this idea of adaptation could be possible for the the organisms living in the water and being negatively affected by the algae? Maybe it could be possible, but at the same time, the organism being affected may die off too quickly before any adaptation could take place.

    Posted by Kayla Perry

  3. Dan, of the other ones is at the Mississipi River. Those are the two largest. There is actually a picture I tried to put on the blog, but I couldn't. It showed where all of these algae blooms take place and in gives an affect of what density.


    In the article I took it as no adaptation is occuring. Giving that the adaptation would need to require life without oxygen I deem it unlikely. In any case, the future looks dim for the water. They mentioned they do not think there is any turning back.

    Posted by Amanda Hostetter