Days after the completion of the Lincoln Memorial Reflecting Pool’s renovations, the “American flag blue” pool turned green because of algae. The Trump administration spent more than $14 million on a no-bid contract to have the bottom of the reflecting pool painted and the seams resealed in preparation for the country’s 250th birthday this summer. The algae were visible from the water’s edge a day after the reservoir was filled and workers could be seen clearing algae from the bottom of the pool last week.An Interior Department spokesperson told CNN the algae is residual and a normal part of the early process of restarting operations at the reflecting pool. “What you are seeing is residual algae from the supply lines, which have been sitting dormant for eight weeks while construction has been taking place. It’s part of the normal startup process. We are removing the algae, and the nanobubblers will maintain the pool and keep it algae free,” communications director Kate Martin said in a statement.Scroll below for a photo timeline of the reflecting pool’s renovation.What causes algae bloom?Algae are plant-like organisms that use sunlight, water and carbon dioxide to create their own food. These organisms thrive in places with warm water temperatures, abundant sunlight and stagnant water.The reflecting pool, which is more than 2,000 feet long, was originally built in the 1920s. Its shallow, slow-moving water has long been prone to appearing green in the summer, particularly when heat, sunlight and stagnant conditions combine.

NEW YORK —

Days after the completion of the Lincoln Memorial Reflecting Pool’s renovations, the “American flag blue” pool turned green because of algae.

The Trump administration spent more than $14 million on a no-bid contract to have the bottom of the reflecting pool painted and the seams resealed in preparation for the country’s 250th birthday this summer.

The algae were visible from the water’s edge a day after the reservoir was filled and workers could be seen clearing algae from the bottom of the pool last week.

An Interior Department spokesperson told CNN the algae is residual and a normal part of the early process of restarting operations at the reflecting pool.

“What you are seeing is residual algae from the supply lines, which have been sitting dormant for eight weeks while construction has been taking place. It’s part of the normal startup process. We are removing the algae, and the nanobubblers will maintain the pool and keep it algae free,” communications director Kate Martin said in a statement.

Scroll below for a photo timeline of the reflecting pool’s renovation.

What causes algae bloom?

Algae are plant-like organisms that use sunlight, water and carbon dioxide to create their own food. These organisms thrive in places with warm water temperatures, abundant sunlight and stagnant water.

The reflecting pool, which is more than 2,000 feet long, was originally built in the 1920s. Its shallow, slow-moving water has long been prone to appearing green in the summer, particularly when heat, sunlight and stagnant conditions combine.