Reviving Dead Zones
by Laurence Mee Nov. 2006
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Source: Scientific American
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Notes-
- In the 1970s and 1980s, incidents of dead sea life have wash ashore in beach resorts in Ukraine and Romania.
- Dead Zones- Areas starved of oxygen and of marine animal life.
- Ocean Researchers believe that "Eutrophication" causes most of the dead zones.
- Eutrophication- The overichment of the sea by nutrients (principally compounds containing nitrogen and phosphorus) that promote plant growth.
- Certain of these fertilizers are involved with the health of phytoplankton and also for the well-being of the sea grass and algae (mostly are found in shallow areas).
- But too much nutrients in illuminated waters can accelerate the plant growth, leading to disruptive algal blooms and other disasters.
- Nitrogen and phosphorus increase the amount of phytoplankton in the water.
- In order to restore the original envorinment, nutrient levels need to decrease to less than what they were.
In the 1970s and 1980s, there were incidents of dead marine life washing up ashore in beach resorts of Ukraine and Romania. By 1990, a dead zone, located in the Southwestern part of the sea near Danube River, extended over an area as the size of Switzerland. Dead zones are areas that have a lack of oxygen or where marine life starve of oxygen, because of river-borne plant nutrients from land that kills the marine life in shallow seas. Also, fertilizing chemicals causes small, macroscopic plants, that float near the surface, to overgrow. This leads to these plants blocking the sunlight for other marine plants, oxygen enters plants through photosynthesis or physical diffusion of air. Without sunlight reaching the plants that are on the bottom of the ocean, organisms die from the lack of oxygen. So the bacteria that feed off these dead organisms use up the oxygen that is left in them. If we cutback the sewage runoff and control overfishing we can restore the damage of theses ecosystems.
Reflection:
While reading this article it made me think that dead zones are a big problem, because it affects marine life by absorbing the oxygen in the water making many organisms to starve for oxygen. One thing I didn't know is that dead zones have been happening around the early 70s and throughout time they are spreading around and getting worse. When macroscopic plants are fertilized by chemicals they overgrow. So, they cover other aquatic plants from recieving sunlight. Without sunlight, plants can't produce photosynthesis or they can't release oxygen in the water for the organisms who need the oxygen. Fish tend to gasp for air, because they need oxygen! Even though, they don't have lungs they tend to breath with their gills, We need to decrease the amount of chemicals we put into the atmosphere that end up going to the waters/ocean, if we want to restore it's ecosystem.