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.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 184.108.40.206.0