Why do these 2 oceans meet but don't mix?

[e.s.]

https://twitter.com/TheMindBlowing/statu...1249519617

[Ron]

Water bodies, like air bodies, that have drastically different properties don't mix easily. They are mixing, but slowly. The boundary of mixing between them is called a front, or mixing zone.

[Jared]

Density and salinity (how salty is is). The denser water sinks below the lighter before they have a chance to mix

[Ricardo]

Failed any science class you may have taken I see.

[Supersonic.]

It's because other one is stronger.