Dead Zone expanding in Gulf of Mexico

Dead Zone expanding in Gulf of Mexico

Scientists from the National Oceanic and Atmospheric Administration and Louisiana State University have predicted that this spring’s record rainfall would produce one of the largest-ever “dead zones” in the Gulf of Mexico.

What are dead zones?

Un-oxygenated “dead zones” appear in waterways wherever algae are overfed by runoff from human activities such as urbanization and agriculture – a phenomenon called eutrophication.

The dead zone in the Gulf of Mexico, fueled by the nutrient-laden water spilling from the mouth of the Mississippi River, is the second-largest in the world.

It blooms every summer, when warming waters accelerate the metabolisms of microorganisms, and it is expected to get even worse as the climate continues to change.

Eutrophication: Major Reason

The primary culprits in eutrophication appear to be excess nitrogen and phosphorus—from sources including fertilizer runoff and septic system effluent to atmospheric fallout from burning fossil fuels—which enter waterbodies and fuel the overgrowth of algae, which, in turn, reduces water quality and degrades estuarine and coastal ecosystems.

Eutrophication can also produce carbon dioxide, which lowers the PH of seawater (ocean acidification). This slows the growth of fish and shellfish, may prevent shell formation in bivalve mollusks, and reduces the catch of commercial and recreational fisheries, leading to smaller harvests and more expensive seafood.

What can be done?

• Improvement of the purifying performance of waste water treatment plants, installing tertiary treatment systems to reduce nutrient concentrations.
• Implementation of effective filter ecosystems to remove nitrogen and phosphorus present in the run-off water (such as phyto-purification plants).
• Reduction of phosphorous in detergents.
• Rationalisation of agricultural techniques through proper planning of fertilisation and use of slow release fertilisers.
• Use of alternative practices in animal husbandry to limit the production of waste water.