Dead Zones In The Gulf Of Mexico

By Nate and Ryan

What is a Dead Zone and what causes them?

A dead zone is caused by excessive nutrient pollution from human activities along with with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water. Also a temperature increase which creates more nutrient rich waters causing more phytoplankton in the area will cause a dead zone. Lastly some causes of these harmful processes are agriculture and the runoff into rivers from the fertilizer also untreated sewage from factories and industries.

Figure 1 to the right shows the overall Dead Zone in the Gulf

Location Description

There are more than half a dozen rivers that empty into the Gulf. The Arkansas, Missouri, and Ohio rivers all feed into the Mississippi River which ends and subsequently filters out in the Gulf of Mexico. Because these four rivers flow though states with a dense farming population and economies that rely on agriculture, a large amount of fertilizers and animal waste are used to protect and create healthy crops. Unfortunately, these then seep into the rivers, collecting more and more of these harmful chemicals as it flows through the country. The end result is that all of the excess fertilizer and waste is pumped into the northern part of the Gulf of Mexico.

Economic Impacts

Due to the dead zone, a massive decrease in the shrimp population as well as shrimp fisherman has been noticed. A local statistic has said that already 25% of the shrimp population is gone already due to the hypoxic state. An estimate total loss of over $650 million in the fishing industry has also contributed to the crippled economy. On the Eastern side of the dead zone a drop in tourists and job opportunities has become a result to the damages in the Everglades.

What can happen to reduce the damage?

Out of the 550 dead zones globally, the Gulf of Mexico is home to the second largest one. Reducing its size and improving living conditions for marine life is crucial to seeing any positive difference in the years to come. One thing that can be done is measuring the amount of fertilizers being used as well as monitoring the time of year which they are used to limit runoff containing high levels of nutrients. Another contributor to this growing problem is human and animal waste, limiting as much as possible from reaching the four major rivers is one of the keys to reversing the damage. Finally, reducing the amount of chemicals at manufacturing facilities within close range of large bodies of water. The key to reducing the size of this dead zone is for a population to make the smart, and conscientious decision when it comes to helping restore the Gulf of Mexico.

Ecological impacts and species impacted by Dead zones

There are many species that can be impacted by dead zones and most of the species are small. Plankton cause the dead zones from dying and using up oxygen then small animals like clams, crabs, lobsters and small fish are affected because they cant swim out of the area; unlike sharks, whales and larger fish that have the power and size to swim away from the area. Some ecological impacts are causing large long lasting areas of the ocean where no animal can survive and ruining habitats.