Nutrient loads can cause problems with water quality. That's why the Missouri Nutrient Reduction Strategy Committee is working to decrease the amount of nutrients that end up in the Mississippi River.
The committee, which is made up of 31 organizations and individuals, formed in 2011 when the Environmental Protection Agency made grants to states in the Mississippi River Basin to develop and implement nutrient reduction strategies.
Before taking steps to reduce the nutrient load, it's important to understand where the nutrients are coming from, said Bob Broz, a University of Missouri Extension assistant professor and member of the committee.
"We're looking at non-point source pollution such as fertilizer use, and we're looking at point source pollution that is produced under different permitting processes," Broz said.
Non-point source pollution comes sources that generally can't be determined precisely, such as runoff from farms, parks and lawns. Broz says non-point source accounts for about 90% of the nutrient load.
The Mississippi River Basin is the third-largest drainage area in the world. Water from parts of 37 states drains into the Mississippi River and ends up in the Gulf of Mexico. If the water has too many nutrients in it, it creates a hypoxia zone, with oxygen levels too low to support most life. Because of this, the hypoxia zone in the gulf has been nicknamed the "dead zone."
Nutrients going into the ocean promote excessive algae growth. When that algae starts dying off, decomposition of all that plant matter removes oxygen from the water, Broz said. "So there is an area where the oxygen is at less than 2 milligrams per liter, which will not support life in most cases."