Swirling bubbles of white foam float slowly on the surface a Scottish river in a hypnotic, constantly changing pattern of organic shapes as a fast river current flows through a green, mossy gorge

river esk north esk stream gorge flowing fresh water river froth moss whitewater ripple swirling dissolved organic carbon water turbulent flow fishing shifting surface float floating cliff surge salmon foam carbon spiral movement foamy swirl foaming contrast pollution circulate bubbles slow patterns twist reflection hypnotic bubble change drift organic fast current spume eddy white