Factsheet – Assessment of nutrient sources and usage during harmful algal blooms (HABs) and algae eutrophication events using stable isotopes: Implications for water quality in the Wabash River

Excessive growth of cyanobacteria and algae in Indiana’s waterways is a persistent and growing problem. Rapid proliferation of cyanobacteria, known as harmful algae blooms (HABs), are of concern because toxins released by decaying bacteria can have adverse health effects on humans, pets, and livestock. They can also bioaccumulate in benthic organisms, which can threaten aquatic ecosystem function and health.

Rapid algal growth, generally referred to as eutrophication, can also have negative ecosystem impacts. Decaying organic matter produced during eutrophication consumes dissolved oxygen, depriving higher organisms of adequate oxygen needed to survive. Much of riverine organic matter generated in the Midwest is transported to the Gulf of Mexico and contributes to coastal hypoxia, known as dead zones, threatening valuable recreational and commercial fishing enterprises. Therefore, understanding the nutrient dynamics that leads to HABs and eutrophication and the source of these nutrients is of great interest to Midwestern and Southern stakeholders.

This project will use isotope analysis to expand our understanding of sources of nutrients in the Wabash River and how these nutrients are utilized by algae and bacteria during transport through the Region of the Great Bend of the Wabash River watershed.