Estuaries

Monitoring Estuaries

temperature | depth | salinity | dissolved oxygen | turbidity | pH | nutrients | chlorophyll

This is a YSI 6000 UPG Multi-Parameter Water Quality Monitor. This particular model measures dissolved oxygen, salinity, temperature, pH, depth, and turbidity. Click on image for more details. (Photo: North Carolina NERRS site)

The National Estuarine Research Reserve System or NERRS is a partnership program between NOAA and U.S. coastal states that protects more than one million acres of estuarine land and water. These estuarine reserves provide essential habitat for wildlife; offer educational opportunities for students, teachers and the public; and serve as living laboratories for scientists.

The health of every reserve is continuously monitored by the NERRS System-wide Monitoring Program or SWMP (pronounced “swamp”). SWMP measures changes in estuarine waters to record how human activities and natural events affect coastal habitats.

The NERRS SWMP uses automated data loggers to monitor the temperature, depth, salinity, dissolved oxygen, turbidity, and pH of each estuary’s water. These variables are recorded every 30 minutes at four stations in each of the 26 NERRS sites. They are key indicators of water quality and environmental conditions for the plants and animals that live in or use the estuary. The reserves also sample the water for nutrients (nitrogen and phosphorus) and chlorophyll on a monthly basis.

Weather can have a major impact on water quality in estuaries. For example, rainfall can increase sediment runoff, which, in turn, influences dissolved oxygen, turbidity, pH and temperature. As part of SWMP, every reserve has a weather station that collects data every 15 minutes on temperature, relative humidity, atmospheric pressure, rainfall, wind speed and direction. Several reserves are able to send real-time data as they are collected directly to Web sites on the Internet.

These data have already helped scientists gain a better understanding of how environmental conditions fluctuate in estuaries. The SWMP data have been used to detect conditions related to oyster diseases, measure the recovery of estuaries after hurricanes, and evaluate restoration projects in estuaries.

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