Because salinity (in concert with temperature) affects the density of seawater, it can play a role in its vertical stratification. Essentially, lower salinity water (= lower density) floats on top of higher salinity water (= higher density).
Alternative definition, a choice limited to one of two or more possibilities, as of things, propositions, or courses of action, the selection of which precludes any other possibility: You have the alternative of riding or walking. See more.
Definition of ALTERNATIVE MEDICINE. : any of various systems of healing or treating disease (as chiropractic, homeopathy, or faith healing) not included in the traditional medical curricula of the United States and Britain.