Dead Zones

A dead zone is an area of bottom water that has very little to no concentrations of dissolved oxygen. Very few organisms can survive this lack of oxygen; so dead zones can destroy the effected habitat. Dead zones are caused usually when there is an algae bloom. When the massive increase of algae die, they sink to the bottom to be decomposed. In order to decompose the increased amount of algae, the bacteria in the water must use more oxygen then normally. This process eventually can lead to a loss of oxygen in that area. The animals then have to either leave the area or die. The smaller animals that form the base of the food chain usually leave or dye out. Making it almost impossible for many other animals to live there. In addition, when an area loses all or most of its oxygen, microbes that thrive in oxygen-free environments, takes over, forming vast bacterial mats that produce hydrogen sulfide, a toxic gas. Location wise, dead zones usually occur along the coasts where this is runoff from other sources.

            Dead zones sometimes occur naturally but human activity is making them dangerously more frequent. One of the main causes of this increase is the fertilizer-runoff from fields into rivers and eventually the ocean. Fertilizer contains large amounts of nitrogen that when added to the ocean, fuel algae blooms. Another cause is the burning of fossil fuels, such as using gasoline in a car. This burning of fossil fuels results in “smog-forming nitrogen oxides”. When it rains, the rain takes the nitrogen out of the air and usually brings the nitrogen down into the ocean.

            Dead zones can cause not just environmental problems, but also economical problems. A hypoxia (having small amounts of oxygen) problem, that occurred in a small area of water in New York and New Jersey in 1976, caused the local fisheries about $500 million. Additionally, about 83,000 tons of fish and other animals are lost in the Chesapeake Bay dead zone each year, enough to satisfy half the commercial crab catch per year.

            For the problem of fossil fuels using electric or hydrogen cars would easily fix this problem, but the fertilizer problem is more difficult. On solution is to breed crops with an adaptation that takes more nitrogen out of the soil. This would minimize the amount of nitrogen that runs off into water. Some crops, such as canola and corn, already have this advancement, and these special seeds can be bought by certain companies, like Monsanto Company and DuPont’s Pioneer Hi-Bred International. However, it is still difficult to stop. A lot of Nitrogen that ends up in water gets buried in sediment. Even though we have taken measures over time to lower the amount of Nitrogen run-off, this sediment slowly releases Nitrogen over time which then starts the cycle over. The damage becomes even worse during natural disasters. During floods, the water takes Nitrogen that would normally stay on land and brings it back to the water. These sources then deposit even more nitrogen into the water, making the cycle even worse.

            Dead zones are a major environmental and economical problem. They cause a major loss in marine habitats and cost local fisheries and commercial fishes a lot of money lost. Although it is very difficult, there are ways that people can solve the problems of dead zones, such as using genetically engineered plants to driving hydrogen or electric cars. They are a big problem now, and if nothing is done about it, they will continue to get worse.