"Salt of the Earth" is Episode 4 in the six-part series "Tides of Change", exploring amazing NASA ocean science to celebrate Earth Science Week 2009. To find out more visit http://climate.nasa.gov/esw Want more? Subscribe to NASA on iTunes! http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=283424434 Or get tweeted by NASA: http://twitter.com/NASAGoddard Salinity plays a major role in how ocean waters circulate around the globe. Salinity changes can create ocean circulation changes that, in turn, may impact regional and global climates. The extent to which salinity impacts our global ocean circulation is still relatively unknown, but NASA's new Aquarius mission will help advance that understanding by painting a global picture of our planet's salty waters.