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.
Alternative payments refers to payment methods that are used as an alternative to credit card payments. Most alternative payment methods address a domestic economy or have been specifically developed for electronic commerce and the payment systems are generally supported and operated by local banks.