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Scientists have claimed that this year’s oceanic ‘dead zone’ in the Gulf of Mexico will be one of the largest ever to be recorded in history. This oxygen-starved and virtually lifeless zone is expected to grow to over 8,000 sq. miles. Scientists predict it will severely harm to marine habitat, impacting fish harvests.

About Dead zone

• It is also called as Hypoxic zones. It is basically area in the ocean having low oxygen concentration, resulting in suffocation and death of marine animal life.
• In this area, oxygen concentration usually falls to such low levels that most marine life cannot survive. Hypoxic zone is reversible i.e. it can be eliminated if their causes are reduced or stopped.
• Occurrence: It can occur naturally. However, manmade activities causing nutrient pollution from sources such as agriculture and sewage also can lead to creation of dead zone.
• Rising sea temperatures: It also exacerbates regional oxygen depletion (as for each degree of ocean warming, oxygen concentration goes down by 2%). It causes layers of ocean water to stratify so more oxygen-rich surface waters are less able to mix with oxygen-poor waters from the deeper ocean.

Gulf of Mexico dead Zone

• It is the world's second largest dead zone (world's largest dead zone is in the Baltic Sea.).. It forms in the Gulf of Mexico every spring.
• Reasons: Each spring as farmers fertilize their lands preparing for crop season, rain washes fertilizer off land and into streams and rivers.
• The mighty Mississippi River which drains into Gulf of Mexico is responsible for collecting and depositing tons of nutrients from agricultural and urban runoff from cities through its course in Gulf of Mexico.