Diving in the halocline.
The halocline is the zone where fresh water meets salt water. Left undisturbed, it looks like the less dense fresh water is floating on the denser and heavier salt water. However, swimming through the halocline creates some wicked visuals as the two mix and swirl together.
Filmed with the Gopro H3B in 1080p/30fps (Protune off) w/ 2 UTD Vision video lights.