Case Study on a National Level

CASE STUDY 2 - National: HYPOXIA, A National Level Erosion Problem

The following case study demonstrates the regional effects of soil erosion and land management on surface water bodies. The case demonstrates how sediments and nutrients associated with sediments make their way to major receiving water bodies, affecting quality of water, survival of aquatic animals and impacting the economy of the fishing and tourism industries.

In the Gulf of Mexico, approximately five thousand square miles of coastal waters are characterized by low levels of oxygen (less than 2 milligrams per liter). This zone has excessive nutrients, primarily nitrogen, carried to the Gulf by the Mississippi and Atchafalaya Rivers. Nutrients and sediments loaded into these rivers are partly contributed from soil erosion induced by different land management practices, including agricultural production and urban development. The overabundance of these nutrients has triggered excessive algal growth (or eutrophication) which results in reduced sunlight penetration, a decrease in oxygen in the water, and death of aquatic animals such as fish. This has also negatively impacted the economy of the fishing industry and tourism. Gulf fisheries provide an estimated $2.8 billion each year to the nation’s economy, while Gulf tourism accounts for approximately $20 billion annually.

Mississippi River Basin erosion contributes to hypoxia in the Gulf of Mexico. Image by the EPA Office of Water

NASA Satellite image of hypoxia in the Gulf of Mexico. Image by NASA

Thinking Question:

With such a large area of the US bread basket draining into the Mississippi River, how will it be possible to create balance between food production and environmental protection?