Potassium is an alkali metal that occurs naturally bound to other elements in seawater and minerals. Mineral aerosols, such as Saharan dust and sea salt, can be the source of water-soluble potassium. Video courtesy of Chere Petty, University of Maryland, Baltimore County; NSF grant DBI-0722569. Note: Microscope video of potassium particles. Animator: Megan Willy (UMBC). Producer: Maria Frostic (UMBC). Scientist: Michael Mischenko (NASA/GISS). Videographer: Chere Petty (UMBC).