In some oceans when the night is dark enough, you can see the waves glow as the water stirs. This is caused by phytoplankton called dinoflagellates. They give off a soft blue glow when disturbed. The chemicals they use are similar to the ones causing lightning bugs to glow.
When a person swims through the algae, the motion gives off a glow all around them, looking like angel's wings. Boats and wave action can also cause ripples of light to cascade in their wake. This video was taken at a dock in Australia where this algae is plentiful. People throw water on it to cause it to glow in amazing patterns.