The Lincoln Memorial Reflecting Pool in Washington, D.C., has turned green with algae just weeks after its bottom was repainted American flag blue and refilled under the Trump administration.
The shallow pool on the National Mall developed the bloom in recent days, turning a verdant hue. Experts attribute the growth to New Pond Syndrome, a common issue after renovations in sunny, stagnant water. Rosalina Stancheva Christova of George Mason University identified the algae as Desmodesmus, which is not toxic.
The Trump administration has responded with hydrogen peroxide and nanobubble ozone technology. As of Thursday morning, workers used vacuums to remove dead algae, though much of the pool remained bright green. An Interior Department spokesperson said the treatments are mild and safe for the environment.
The project cost rose from an initial $2 million estimate to at least $14 million. The pool has faced similar algae issues after past renovations, including in 2012 and 2019.
