The Gulf of Mexico's Connecticut-sized dead zone is proving hard to kill

2014 Gulf of Mexico Dead Zone
Public Domain NOAA

We need to take our efforts up a notch or two

When you buy something from a farm that overuses fertilizer, you might be unknowingly doing your small part to create a low-oxygen 'dead zone' in the ocean thousands of miles away. The extra fertilizer runs off into local streams and rivers, which make their way to the ocean. In a large part of the US, that means via the Mississippi river, which ends up in the Gulf of Mexico. Once there, the high concentrations of fertilizer "stimulate an overgrowth of algae that sinks, decomposes and consumes most of the oxygen needed to support life." Not much life without oxygen, hence the dead zone.

Hypoxia dead zone graphEPA/Public Domain

If you want to learn more about hypoxic zones, aka dead zones, the video below is a great primer:

The Environmental Protection Agency (EPA) has created a plan in 2008 to reduce these agricultural runoffs, with a task force composed of 5 federal agencies, 12 states and the tribes within the Mississippi/Atchafalaya River Basin. The goal is to reduce by 45% nitrogen pollution to reduce the size of the Gulf dead zone to less than 1,930 square miles (5,000 square kilometers).

NOAA reported a 5,052 square miles dead zone in the Gulf last summer... It's better than in 2013 when the dead zone was 5,840 square miles, but still, it's not so great.

A new study found that the current voluntary actions are not enough, but that if they were supplemented with other actions, such as "restoring wetlands in marginal corn and soybean fields and within river and stream paths, [enhancing drainage ditches,] as well as reconnecting rivers with their floodplains," they could be significantly more effective.

"The good news is that adopting soil health and fertilizer efficiency measures across the Corn Belt can get us two-thirds of the way to the tipping point," said the study's lead author and EDF senior scientist, Eileen McLellan, in a news release. "But by strategically placing wetlands on less than 1 percent of the region's croplands, we'll be able to reverse the trend of significant losses in aquatic life, and improve flood resiliency for downstream communities with minimal impact to crop production," she added.

"The results show that we need to start thinking about conservation not just at the scale of an individual farm but also at the watershed scale," said Dale Robertson, research hydrologist at the Geological Survey's Wisconsin Water Science Center and co-author of the paper. "Improving water quality is a community-wide effort that will save money, clean up local streams, and benefit the Gulf."

This isn't just a problem in the Gulf of Mexico, far from it. Below is a map showing the location of major oceanic dead zones around the world:

Dead zonesWikipedia/Public Domain

As the name implies, the low oxygen level in a dead zone is fatal to many creatures. It's not pretty...

dead zone photo

Via Journal of the American Water Resources Association, NOLA

Tags: Agriculture | Water Conservation | Water Crisis

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