For years, Iran’s Lake Urmia has been vanishing, thanks to droughts, rising temperatures, and poor water management. Now, NASA’s Aqua satellite has fingered another source of the saltwater lake’s woes: algae and bacterial blooms. National Geographic reports that recent satellite images of the lake have shown it turning from a dark green color to a dark red, indicative of a microalgae called Dunaliella salina. As the lake reduces in size, it also grows saltier, making it a great breeding ground for the algae, which turns the water blood-red. Usually, rain and melting snow in the spring return freshwater to Lake Urmia, stabilizing the salinity. But as a drought and agricultural use continues in the region, it is likely that such algal blooms may become more common.