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USGS: Real-time Monitoring Tracks Nitrate Pulse in Mississippi River

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Image source: USGS

Cutting edge optical sensor technology is being used in the Mississippi River basin to more accurately track the nitrate pulse from small streams, large tributaries and ultimately to the Gulf of Mexico.

Excessive springtime nitrate runoff from agricultural land and other sources in the Mississippi drainage eventually flows into the Mississippi River. Downstream, this excess nitrate contributes to the Gulf of Mexico hypoxic zone, an area with low oxygen known commonly as the "dead zone." NOAA-supported researchers reported that the summer 2013 dead zone covered about 5,840 square miles, an area the size of Connecticut.

These optical sensors measure and transmit nitrate data every 15 minutes to 3 hours and are located at the mouth of the Mississippi River near Baton Rouge, LA, and at several large tributaries to the Mississippi River—including the Missouri River at Hermann, MO; Ohio River at Olmsted, IL; Ohio, Illinois River at Florence, IL; and Iowa River at Wapello, IA – to track how nitrate concentrations from different areas of the watershed pulse in response to rainfall and seasons.