
Living "outside" for thousands of years (evolution) causes the skin of a person to produce melanin, a pigment that colors people's skin and protects from the sun's ultraviolet rays.

I think her skin is darker because the Atlantian people live outside (in their bubble), not sheltered as much under buildings who shield pale persons. I just thought since she is dark-skinned, she would be consider Black, but she's not considered Disney's first Black princess.
