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.
As nouns the difference between justification and rationale. is that justification is a reason, explanation, or excuse which provides convincing, morally acceptable support for behavior or for a belief or occurrence while rationale is an explanation of the basis or fundamental reasons for something.