Swirling bubbles of white foam floats on the surface of dark, black water in a Scottish river in a hypnotic, constantly changing pattern as a shallow depth of field highlights the centre of the frame

flowing north esk ripple swirling river whitewater stream fresh water dissolved organic carbon water turbulent froth flow float foam swirl carbon floating movement shifting surface bubbles fishing surge shallow depth of field spiral nature foamy circulate salmon shallow twist reflection hypnotic bubble patterns foaming fast drift slow black dark contrast change pure organic eddy current white