How does the Gulf of Mexico dead zone affect food webs in the area?
The most well-known area of low dissolved oxygen and related problems occurs in the northern Gulf of Mexico and is commonly known as the “dead zone.” Hypoxia in this zone strongly impacts pelagic food webs and fish production through several pathways, likely leading to changes in production potential (both positive and …
What is the deadzone in the Gulf of Mexico?
The hypoxic zone in the northern Gulf of Mexico is an area along the Louisiana-Texas coast, where water near the bottom of the Gulf contains less than two parts per million of dissolved oxygen, causing a condition referred to as hypoxia. Each summer, the size of the hypoxic zone is measured.
How are nutrients in the Gulf of Mexico contributing to dead zones?
When the excess nutrients reach the Gulf, they stimulate an overgrowth of algae, which eventually die and decompose, depleting oxygen as they sink to the bottom. The resulting low oxygen levels near the bottom of the Gulf cannot support most marine life.
Why is the Northern Gulf of Mexico described as a dead zone?
An expansive portion of the northern Gulf of Mexico, stretching from Texas to Florida, has very low oxygen levels. Those levels sink even further every summer, creating a hypoxic or “dead” zone, so named because the lack of oxygen makes the area inhospitable to fish and marine life.
Why are dead zones a problem?
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.
How can we fix the dead zone in the Gulf of Mexico?
Solutions include:
- Using fewer fertilizers and adjusting the timing of fertilizer applications to limit runoff of excess nutrients from farmland.
- Control of animal wastes so that they are not allowed to enter into waterways.
How long does a dead zone last?
Among the 27 OMZ signals identified – indicated by ‘laminated’ layers in the core, reflecting undisturbed sediment laid down in the absence of living creatures – some of the dead zone intervals lasted for less than a thousand years, while in others the hypoxic conditions persisted for close to 40 millennia.
Can a dead zone be reversed?
Fortunately, dead zones are reversible if their causes are reduced or eliminated. For example, a huge dead zone in the Black Sea largely disappeared in the 1990s following the fall of the Soviet Union, after which there was a huge spike in the cost of chemical fertilizers throughout the region.
How does the Gulf of Mexico dead zone affect humans?
The National Oceanic and Atmospheric Administration, or NOAA, estimates that the dead zone costs U.S. seafood and tourism industries $82 million a year. The impact could be devastating to the Gulf’s seafood industry, which accounts for more than 40 percent of the nation’s seafood.
How do dead zones affect humans?
Elevated nutrient levels and algal blooms can also cause problems in drinking water in communities nearby and upstream from dead zones. Harmful algal blooms release toxins that contaminate drinking water, causing illnesses for animals and humans.
What are the three main causes of the dead zone?
Nitrogen and phosphorous from agricultural runoff are the primary culprits, but sewage, vehicular and industrial emissions and even natural factors also play a role in the development of dead zones.
What is the largest dead zone in the world?
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.