An underwater photograph of a rock, taken in bright sunlight, covered in a purple-brown mat of Cyanobacteria that is itself covered in oxygen bubbles from photosynthesizing. Some bright green algae occur over the Cyanobacteria. The rock is reflected in the water.

More #cyanobacteria. This time an underwater shot of a cyanobacterial mat with oxygen bubbles of, most likely, #Phormidium sp. #Ulva sp. also present.