Challenge #2: Reduced Water Quality


Challenge #2: Reduced Water Quality

Nutrients such as nitrogen and phosphorus, and suspended soil sediments have greatly diminished water quality (USEPA, 2017a). Polluted water with unusually high concentrations of dissolved or suspended materials, or small amounts of highly toxic materials can be detrimental and sometimes even deadly to living things. Civilization has many uses for and is dependent on high-quality water (Troeh et al., 2004).

Major agricultural contributions to reduced water quality include:

  • Nutrient loading in water systems from nitrogen and phosphorus
  • Increased suspended sediment from soil erosion.

“Midwest land under heavy agricultural production has been identified as a major contributor to nitrogen and phosphorus losses to downstream water systems and to hypoxia in the Gulf of Mexico” (Helmers, 2014).

Large amounts of agricultural fertilizers, specifically nitrogen and phosphorus, are lost from agricultural fields each year. Nitrogen and phosphorus nutrient loss occurs via soil erosion, surface runoff, and leaching into groundwater. Nutrient loss from agricultural fields negatively impacts downstream water systems.


Hypoxia zone in the Gulf of Mexico - One major problem caused from nutrient loss.

“America's treasured Gulf of Mexico ecosystems are composed of a mosaic of coral reefs, wetlands, marshes and sea grass meadows. Private agriculture and forestlands account for 90 percent of the landscape in the five Gulf states, Alabama, Florida, Louisiana, Mississippi and Texas. Consequently, the management of private lands significantly influences the health of the region's economies, tourism and the natural resources, which keep the Gulf of Mexico thriving.

But the health of the Gulf of Mexico region has deteriorated significantly because of factors such as: the loss of critical wetland habitats, imperiled fisheries, water quality degradation and significant loss of coastal lands. The Gulf Coast region also has endured significant natural and man-made catastrophes in the last decade, including major hurricanes and the 2010 Deepwater Horizon oil spill” (NRCS, 2017g).

Click HERE to learn about the Gulf of Mexico Initiative(GoMI), founded by the NRCS in 2010 as a comprehensive effort to collaborate with federal and state agencies and groups to restore surrounding watersheds and promote voluntary conservation in the region.

Click the picture below to download the PDF article (retrieve from your downloads folder to view):

Article_Keeping Midwestern Soils Out of the Gulf

Hypoxia Basics:

What is Hypoxia?

Hypoxia means low oxygen and hypoxic waters have dissolved oxygen levels of less than 2-3 ppm (USEPA, 2017b).

What causes Hypoxia?

A variety of factors can cause hypoxia such as excess nutrients which includes nitrogen and phosphorus in the water and waterbody stratification (layering) due to saline or temperature gradients (USEPA, 2017b).

Nutrients can come from many sources; the primary sources include:

  1. Fertilizers from agriculture, golf courses, and suburban lawns
  2. Erosion of soil full of nutrients
  3. Discharges from sewage treatment plants
  4. Deposition of atmospheric nitrogen

What are the effects of Hypoxia?

The increase of excess nutrients, including nitrogen and phosphorus cause eutrophication and promote algal growth. Oxygen is consumed when the dead algae decomposes resulting in low levels of oxygen in the water (USEPA, 2017b).

A few specific direct effects of hypoxia:

  • fish kills
  • mussel or crab kills
  • decrease in aquatic life
  • loss of food and habitat


Click the link to learn more about: The Hypoxic Zone: What is Hypoxia?


Iowa’s Role in Reducing Gulf Hypoxia

In 2008, the Hypoxia Task Force, which was established by the US EPA, directed twelve states, including Iowa, to develop “comprehensive nitrogen and phosphorus reduction strategies encompassing watersheds with significant contributions of nitrogen and phosphorus to the surface waters of the Mississippi/Atchafalaya River Basin (MARB), and ultimately to the Gulf of Mexico” (USEPA, 2017a).

Specifically, a target goal to reduce total nitrogen and total phosphorus loads by 45% has been established by the Gulf Hypoxia Action Plan.

To help achieve this 45% reduction, Iowa developed a statewide plan called the Iowa Nutrient Reduction Strategy. The volunteer program is designed to help farmers reduce the amounts of nutrients leaving the State. Eleven other Hypoxia Task Force states have also developed nutrient reduction strategies and they can be viewed here:

Hypoxia Task Force Nutrient Reduction Strategies

Click HERE to listen to an Iowa Public Radio program about Iowa's contributions to Gulf Hypoxia, its impact on the Louisiana shrimpers, and what Iowa farmers are doing about it.


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