Nitrogen, phosphorus, sunlight, and stagnant water can combine to create the perfect conditions for algal blooms

Public service announcement for anyone planning to visit Washington, D.C., in the immediate term: Steer clear of President Donald Trump’s hot mess of a reflecting pool.

The pool’s unexpected color change sparked a wave of viral memes, with social media users recasting the iconic landmark as everything from a swampy Star Wars set to a Bob Ross landscape.