for the very lovely and talented artist jemimalovesbigted

In the summer of 2000, sudden summer storms washed large amounts of nutrients into Port Phillip Bay. These nutrients caused blooms of microscopic algae called dinoflagellates. The increased nutrients and warm water meant that these planktonic organisms may be present in sufficient numbers to colour the water. This happened late in November and the eastern shores of Port Phillip Bay were stained red by an algal bloom.
Although the dinoflagellates were apparently not toxic, they were able to glow in the dark. During this phenomenon, many locals would arrive on the beach shores at night, pick up a hand full of sand and throw it into the sea to see it glow in the dark.

Bioluminescence is simply light produced by a chemical reaction which originates in an organism.
Bioluminescence is a primarily marine phenomenon. It is the predominant source of light in the largest fraction of the habitable volume of the earth, the deep ocean.
Bioluminescent bacteria occur nearly everywhere, and probably most spectacularly as the rare “milky sea” phenomenon, particularly in the Indian Ocean where mariners report steaming for hours through a sea glowing with a soft white light as far as the eye can see.