Restoring oxygen-depleted areas to the thriving ecosystems they once were by tackling root causes such as agricultural runoff is not only possible but also imperative. In some areas of water, however, agricultural chemicals have built up over time and caused so much damage that the recovery process may take decades.
A new study has found that even if runoff of nitrogen, a fertilizer chemical, was fully stemmed, the Gulf would take about 30 years to recover.
Types of Dead Zones
Permanent dead zones occur in very deep water. Oxygen concentrations rarely exceed 2 milligrams per liter. Temporary dead zones are hypoxic regions that last for hours or days. Seasonal dead zones occur every year during the warm months.
The best way we can reduce algal blooms and dead zones is to implement the Blueprint by putting in place best management practices that control pollution from urban and agricultural lands, as well as wastewater treatment plants and septic systems.
Because most organisms need oxygen to live, few organisms can survive in hypoxic conditions. That is why these areas are called dead zones. Dead zones occur because of a process called eutrophication, which happens when a body of water gets too many nutrients, such as phosphorus and nitrogen.
The largest dead zone in the world lies in the Arabian Sea, covering almost the entire 63,700-square mile Gulf of Oman. The second largest sits in the Gulf of Mexico in the United States, averaging almost 6,000 square miles in size.
To get a cell signal in a dead zone, it's pretty simple. All you need to do is to invest a cell phone signal booster.
Dead zones are areas of water bodies where aquatic life cannot survive because of low oxygen levels. Dead zones are generally caused by significant nutrient pollution, and are primarily a problem for bays, lakes and coastal waters since they receive excess nutrients from upstream sources.
What types of dead zones (hypoxia) exist? Different water bodies can experience hypoxia for long or short periods. Scientists classify water bodies in four broad categories: Permanent, temporary, seasonal, and diel cycling.
Dead zones are the most severe result of eutrophication. This dramatic increase in previously limited nutrients causes massive algal blooms. These "red tides" or Harmful Algal Blooms can cause fish kills, human illness through shellfish poisoning, and death of marine mammals and shore birds.
Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning.
The dead zone doesn't directly affect humans perse, since we don't rely on getting oxygen from the water. BUT, high levels of polluted runoff are a concern. For one, other pollutants like harmful bacteria are also washed into our waterways during rain events.
Hypoxic zones can occur naturally, but scientists are concerned about the areas created or enhanced by human activity. There are many physical, chemical, and biological factors that combine to create dead zones, but nutrient pollution is the primary cause of those zones created by humans.
Then the dead zone dissipates in the fall and winter when the flow of nutrients slow down and temperature and other conditions are more favorable for the water in the Gulf to more readily mix together. Then it starts all over again during the next spring.
The majority of the world's dead zones are along the eastern coast of the US, and the coastlines of the Baltic States, Japan and the Korean Peninsula. Notable examples include the Gulf of Mexico and the Baltic Sea. The Gulf of Mexico has a seasonal hypoxic zone that forms every year in late summer.
The key to reducing the size and number of low-oxygen dead zones in coastal waters is to reduce the input of nutrients into estuaries and the coastal ocean. Nutrient-reduction strategies are a key part of efforts to restore the health of Chesapeake Bay.
Scientists have determined this year's Gulf of Mexico “dead zone,” an area of low oxygen that can kill fish and marine life, is 8,776 square miles, an area about the size of New Jersey. It is the largest measured since dead zone mapping began there in 1985.
How does a dead zone form? Each spring, our coast is dominated by winds that blow from the north to the south. This wind is the engine behind ocean currents that move cold water up from the deep ocean to the coast. The upwelled water is naturally low in oxygen.
There are at least 700 known dead zones, and even if all of them were the size of the one in the Arabian Sea—over 60,000 square miles—that would account for about one percent of the world's total ocean area.
Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold.
What Causes the Dead Zone? Heavy rains and melting snows washed massive amounts of nutrients—particularly nitrogen and phosphorus—from lawns, sewage treatment plants, farm land and other sources along the Mississippi River into the Gulf of Mexico.
Dead zones occur anywhere and everywhere. They exist in rural areas, cities, deserts, roadsides, and even between buildings and indoors. The easiest way to know if you've crossed into a dead zone is to check your cell phone signal strength. Or just look at the bars on your phone.
The Dead Zone is a science fiction thriller novel by Stephen King published in 1979. The story follows Johnny Smith, who awakens from a coma of nearly five years and, apparently as a result of brain damage, now experiences clairvoyant and precognitive visions triggered by touch.
This lack of oxygen creates the Dead Zone in bottom waters on the Texas-Louisiana shelf throughout warm summer months. This occurs when there are fewer storms and strong winds to mix the warm, oxygenated surface waters and the cooler, deeper waters.
Today, NOAA-supported scientists announced that this year's Gulf of Mexico “dead zone”— an area of low to no oxygen that can kill fish and marine life — is approximately 3,275 square miles.