Researchers at University of Waterloo published a study in Science in late March of 2018 giving new insight into the fact that restoring the water quality in the Gulf of Mexico is harder than originally thought. The Gulf of Mexico contains a hypoxic or dead zone, an area found in bodies of water that have extremely low levels of oxygen due to excessive nutrient pollution from human activities. Recently, attempts have been made to reduce the size of the Gulf’s dead zone, but despite these investments of large amounts of money, researchers have concluded that the legacy of nitrogen is so intense that these goals are unrealistic.
This dead zone is due to large quantities of nitrogen being carried through rivers and streams across the North American corn belt to the Gulf. Massive algal blooms sparked by the concentration of nitrogen leads to oxygen depletion, making it more difficult for marine life to survive. Due to its continual expansion, this area is approximately the size of New Jersey, and will continue to grow unless drastic measures are taken. Major changes in agricultural and river management practices must be made in order to see any type of improvement of water quality.
Researchers compiled and analyzed more than two centuries of agricultural data, showing that nitrogen has been accumulating in soil and groundwater due to intensive agricultural production. The water quality of the Gulf of Mexico has been declining since the 1950’s. It’s hypoxic zone is mainly caused by use of fertilizer and intensive livestock production. Manure and fertilizer are both rich in nitrogen, and can easily enter watersheds through runoff.
After this analysis, researchers modeled the results and concluded that even under best-case scenarios where effective conservation measures are implemented instantly, it would take over 30 years to restore the Gulf of Mexico through depletion of excess nitrogen. They continue their analysis to phosphorus, which is a major instigator of algal blooms in inland waters
The need for intensive agricultural production is only increasing, nitrogen quantities will continue to rise do to this, creating a massive problem for marine life around the globe. Effective policy must be implemented to curb the growth of this massive dead zone in the Gulf of Mexico, which imposes a great risk on marine ecosystems all over the region.
K. J. Van Meter, P. Van Cappellen, N. B. Basu. Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico. Science, 2018; eaar4462 DOI: 10.1126/science.aar4462