White River Fish Kill was Caused by Algae Bloom

INDIANAPOLIS, IN - A fish kill in the White River near Rocky Ripple in Marion County noticed by members of the public late last week appears to be the result of an excessive algae bloom.

Both DNR and IDEM dispatched investigators on July 24, after several reports from concerned citizens. Neither agency found evidence of a spill, but instead found brownish water and scummy algae on the water's surface.

Lenore Tedesco, director of IUPUI's Center for Earth and Environmental Science, collected water samples in the area on July 24 and 27, and documented a diatom algae bloom.

According to Tedesco, such algae blooms can cause fish kills.

"When the algae are in very high concentrations, like they are right now in the White River, they make oxygen during the day, but rob oxygen from the water at night," she said. "Without enough oxygen, fish will basically suffocate."

Tedesco said that while algae are natural in streams and lakes, excessive growth like this is not natural.
 
"Right now we are seeing algal blooms in many of our (local) freshwater systems," Tedesco said. "This is typical in middle to late summer and suggests excessive nutrients in the water."