What are nitrogen and phosphorus and where do they come from?
Nitrogen and phosphorus are both nutrients that are essential to living life. When there are high levels of these nutrients in an environment, they become harmful and cause devastating effects on wildlife and the ecosystem.
The most prominent pollutant source is fertilizers, which are used to increase crop yield in agriculture and on lawns by homeowners. Animal waste contains an abundance of nutrients. In the livestock industry, most of the animal waste is improperly stored and ends up in waterways. Leaves that fall from trees are also a pollutant source. Leaves that aren't raked or disposed of properly end up in storm drains and enter the wastewater system. As the leaves decay, they release nitrogen and phosphorus into bodies of water.
How do these nutrients find their way to the Mississippi River?
Two main reasons nitrogen and phosphorus are able to enter waterways is due to agricultural practices and impervious surfaces in suburban and urban areas.
More than 70% of nitrate, a form of nitrogen, comes from cropland. Nutrients from fertilizers leach into groundwater and later enter bodies of water. Tiling, an practice of breaking up and stirring cropland to prevent weed growth and mix in organic matter, allows more nitrate to enter the groundwater because the soil is broken up and unable to take up nutrients as it filtrates through.
Impervious surfaces, like sidewalks and roads, block water filtration through the soil. Instead, water from rain or snow becomes runoff and enters the storm sewer system. As the water travels along the impervious surfaces, it takes along excess fertilizer and soil, which both contain nitrogen and phosphorus,
What effects do the nutrients have on the Mississippi River?
The abundance of nutrients allows algae to grow at significantly higher rates that become too much for the ecosystem to handle, these are called algal blooms. The algae block sunlight and clog fish gills. They may also create toxins that are detrimental to fish and will move up the ecosystem to affect larger animals. When these algae die, bacteria help decompose the algae. This process uses up the available oxygen in the ecosystem. Without oxygen, fish and other wildlife living in these areas are unable to survive and die.
What can you do?
Though it may seem that one person can't contribute to such a large problem, if everyone did something little to help, we can see changes quickly. Here are some little things you can do in your own home and community to contribute to the change:
Pick up after your pet and avoid walking them near waterways
You can walk your pets in parks and grassy areas to decrease the probability of nutrients from animal waste entering waterways
Apply the recommended amounts of fertilizers and only when necessary
Don't apply fertilizers if it will rain or if it is windy
Plant native plants to help filter rainwater as it filtrates through the ground
Help spread the word and educate those around you to raise awareness on the issue
Sources
Nutrient Reduction In Mississippi – MDEQ. 1 May 2010, https://www.mdeq.ms.gov/water/surface-water/nonpoint-source-pollution-program/nutrient-reduction-in-mississippi/.
"Pollution on the Mississippi River." Lake Forest College, https://www.lakeforest.edu/academics/majors-and-minors/environmental-studies/pollution-on-the-mississippi-river.
---. Lake Forest College, https://www.lakeforest.edu/academics/majors-and-minors/environmental-studies/pollution-on-the-mississippi-river.
Slamdot, Inc. "Nitrogen & Phosphorus Pollution | Mississippi River Collaborative." Mississippi River Collaborative | Mississippi River Collaborative, 28 July 2014, https://www.msrivercollab.org/focus-areas/nitrogen-phosphorus-pollution/.
https://www.epa.gov/sites/default/files/2015-03/documents/epa-marb-fact-sheet-112911_508.pdf.