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 depleted oxygen zone in the Gulf of Mexico growing?
The dead zone is caused by nutrient enrichment from the Mississippi River , particularly nitrogen and phosphorous. ... In a natural system, these nutrients aren’t significant factors in algae growth because they are depleted in the soil by plants.
How does oxygen get depleted in the Gulf of Mexico?
Hypoxia is believed to be caused primarily by excess nutrients delivered from the Mississippi River in combination with seasonal stratification of Gulf waters. ... Stratification of fresh and saline waters prevents oxygen replenishment by mixing of oxygen-rich surface water with oxygen-depleted bottom water.
What is the main driver causing the hypoxia zone in the Gulf of Mexico?
The annually recurring Gulf of Mexico hypoxic zone is primarily caused by excess nutrient pollution from human activities , such as urbanization and agriculture, occurring throughout the Mississippi River watershed.
What causes oxygen depleted zones in the ocean?
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. At normal levels, these nutrients feed the growth of an organism called cyanobacteria, or blue-green algae.
Is there a dead zone 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.
Who is responsible for the Gulf of Mexico dead zone?
The primary culprit responsible for the growing size of the dead zone is an increasing supply of nitrogen dumped into the Gulf of Mexico from the Mississippi River .
What can Louisiana citizens do to fix the Gulf of Mexico dead zone problem?
HOW CAN LOUISIANA HELP REDUCE THE DEAD ZONE? ... River diversions are restoration projects designed to build and sustain Louisiana’s coastal wetlands. These wetlands can also help filter and remove nutrients from the river, fueling wetland plant growth while also reducing nutrients that cause the Gulf of Mexico Dead Zone.
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.
How many dead zones are in the ocean?
According to a new study in Science, the rest of the world fares no better—there are now 405 identified dead zones worldwide, up from 49 in the 1960s—and the world’s largest dead zone remains the Baltic Sea, whose bottom waters now lack oxygen year-round.
Is the water in the Gulf of Mexico clean?
Data from the Occupational Health & Safety Administration (OSHA) show that clean-up and repair workers in the Gulf of Mexico near the spill have not been exposed to harmful levels of toxins, said Robert Emery, vice president for safety, health, environment and risk management at the University of Texas Health Science ...
Why can’t fish live in the Gulf of Mexico dead zone?
The 2020 Gulf of Mexico Hypoxic Zone, or Dead Zone, an area of low oxygen that can kill fish and marine life near the bottom of the sea, measures 2,116 square miles. ... This is hypoxia – when oxygen in the water is so low it can no longer sustain marine life in bottom or near bottom waters – literally a dead zone.
What problems does the Gulf of Mexico have?
The Gulf is now more vulnerable than ever. Today, the Gulf continues to face ongoing threats such as invasive species, extreme storms and flooding, and land loss . Future issues like sea level rise and a growing coastal population add further stress to the people and wildlife who call the Gulf home.
How can we fix ocean dead zones?
Conservation tillage : Reducing how often fields are tilled reduces erosion and soil compaction, builds soil organic matter, and reduces runoff. Managing livestock waste: Keeping animals and their waste out of streams, rivers, and lakes keep nitrogen and phosphorus out of the water and restores stream banks.
What are dead zones in the ocean?
Less oxygen dissolved in the water is often referred to as a “dead zone” because most marine life either dies, or, if they are mobile such as fish, leave the area. ... Dead zones occur in coastal areas around the nation and in the Great Lakes — no part of the country or the world is immune.
How do dead zones happen?
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. Excess nitrogen and phosphorus cause an overgrowth of algae in a short period of time, also called algae blooms.
