There is a place in the Gulf of Alaska where two oceans meet but do not mix. Fresh water glaciers melted and flowed to join the ocean water, but because of the difference in the salinity and densities of these two water bodies, a surface tension developed between them that acts like a thin wall which prevents them from mixing. The boundary between the two is outlined by a thin layer of foam.
According to scientists, given enough time, the differences between
these two bodies will disappear and they will merge together.