Photo by Yonas Hassen

D.C.’s recent sweltering heat is partly responsible for the death of hundreds of fish on the National Mall.

The heat wave has created two problems for the fish, Mike Litterst of the National Park Service told DCist. Because the pond is very shallow, the water temperature quickly rises to a level that the fish can’t tolerate “and the dissolved oxygen levels in the water drop,” he says. In addition, the warm weather spawns algae blooms, “which in turn can further rob the water of oxygen needed by the fish when the algae dies off.”

Authorities have found no indication of a hazardous material or pollutant in the water, Litterst adds.

Officials found a mix of dead bluegill, sunfish, and bass at the pond at Constitution Gardens, according to The Washington Post.

This particular body of water has been troubled in the past as well. In 2013, park officials found about 1,000 dead fish floating in the pond.

As the odor drifts through the air, officials are working quickly to collect the remains, Litterst says. And the National Park Service has long-term plans to upgrade the pond to become a “better ecological environment.” according to The Post.