Lake Erie. That’s how big this year’s dead zone—the largest ever—in the Gulf of Mexico is likely to be, according to National Ocean and Atmospheric Administration predictions.
Dead zones (aka hypoxic zones) are low-oxygen aquatic areas that can no longer support life. They form when algal blooms, fed by nutrient pollution, eat up all available oxygen. Much of this pollution enters the water far upstream in the form of nutrient run-off from farm fields. For the Gulf of Mexico, it’s the corn and soybean fields of the Upper Mississippi River Basin that are the primary nutrient contributors.
There are lots of elements that contribute to dead zone formation, but this year’s record-breaker is the result of three primary factors:
- Climate change, which is making “freak” weather events like flooding and droughts the norm
- Monoculture industrial agriculture systems that rely heavily on synthetic nutrients and don’t hold on to them very well
- An overly engineered river system made up of locks and dams (in place to manage navigation, not flooding) that has isolated the river from its floodplains and limited its natural resiliency and ability to self-regulate
Dead zones are a huge problem with huge costs; estimates put the damage to the U.S. economy at about $82 million annually from algal blooms, affecting everything from the gulf’s fishing industry to public health. Add in the dollars that flow off the farm in the form of nutrient run-off (as fossil fuel prices rise, so do fertilizer costs) and you have one very expensive problem.
Fortunately, the solutions come relatively cheap.
In the short term, farmers need to improve nutrient management on the farm to make sure they apply the right amounts at the right times to minimize run-off. In the medium term, we need to help farmers transition to better farming systems based on perennials and crop diversity, systems that require fewer nutrient inputs and that can hold on much better to those they do need. There are many farmers already moving in these directions, and they need as much support as we can give them.
Second, we need to restore our river systems to make the Mississippi and its tributaries more resilient to flooding. The U.S. Army Corps of Engineers would like to see us go the opposite direction by spending billions of dollars to build more locks and dams along the rivers, a request that is not only wasteful and unnecessary, but would further degrade the river environment. As the planet warms, increased resiliency of all our natural systems—waterways and agriculture included—will be paramount.