Assessing the condition of Great Rivers using benthic and planktonic algal indicators

Abstract

The U.S. Environmental Protection Agency Environmental Monitoring and Assessment Program embarked on a comprehensive survey of Great Rivers in order to provide tools the states need to better manage and protect these important national resources. This survey collected indicators intended to measure the health status of the Missouri, Mississippi, and Ohio Rivers. Measured parameters included indicators of water quality, sediments, algae, plants, insects, and fish. The Natural Resources Research Institute developed indicator tools from the algae, collected from hundreds of sites throughout the Great Rivers system. Indicators are now available to track ecological quality using periphytic and phytoplanktonic algal assemblages. These indicator approaches will support future monitoring and paleoecological programs, and be used to identify and verify reference locations in rivers. Algae are well-known to respond to stressors in rivers such as nutrient and salinity loading, siltation, and other factors affecting water clarity. We took a comprehensive approach to develop indicators (metrics and indices) for large river ecosystems using proven methods suitable for large rivers nationwide. A multi-tiered approach integrating landscape, biological communities, and chemical characteristics was applied to characterize sites.