In strongly acidified lakes, the primary biological response might be a massive proliferation of thread-like algae. Amongst a lot of ecological ramifications, these algae might act as a diffraction grating for incident sunlight. The phenomenon is plainly visible in this underwater scene with diatomaceous algae and pads of hybrid Yellow Water lily (Nuphar lutea x pumila).
Nikon 1AW1 + AW 10 mm f/2.8