The turquoise lake in the crater of the Kawah Ijen volcano is the world's largest acidic lake. The water in the crater lake has a pH less than 0.3 on a scale of 0 to 14 (7 is neutral). For comparison, lemon juice has a pH of 2; battery acid has a pH of 1. That acidity affects the chemistry of nearby river ecosystems, including the river Banyupahit. Originating at the lake, the Banyupahit delivers acidic water to populated areas downstream. According to a 2005 research paper, the river water that local farmers use to irrigate crops has a pH between 2.5 and 3.5. The normal range for stream water, according to the U.S. Geological Survey, is between about 6 and 8. On August 22, 2013, the Operational Land Imager (OLI) on Landsat 8 captured this view of the lake in East Java, Indonesia. The turquoise color comes from the range of materials dissolved in the water, including hydrochloric and sulfuric acids. The plume drifting west from the crater likely comes from fumaroles, which release hot gases from underground magma.