Bioluminescence!

To the naked eye the bioluminescence appeared as a milky glow in the wash of the propellers. At first we thought it was simply the ships lights shining on the cavitation bubbles of the prop wash, but it quickly became clear that there were no lights shining, and that the glow had a biological source instead of an artificial one.

With the aid of long exposure photography, the true color of the emitted light becomes apparent and even more beautiful.

Bioluminescent seas like the ones we experienced are caused by the glow of a type of planktonic algae called a dinoflagellate. These single celled protists live in all types of aquatic environments (even snow and ice!) but the dinoflagellates we observed live near the sea surface where they can photosynthesize during the day. Their bioluminescence is stimulated when they are disturbed which causes them to emit a short flash of light. What we see is the combined effect of millions of dinoflagellates all flashing on and off as they are stirred up by the ship’s thrusters.

Aiding the dinoflagellates in lighting up the seas were the flashing lights of the larger and more illuminate (but much less in number) Water Jelly (Aequorea Victoria). These provided quick bursts of light in the cloudy blue of the dinoflagellate light, like flashes of lightning in distant stormclouds.

Valiadi M, Iglesias-Rodriguez D. Understanding Bioluminescence in Dinoflagellates-How Far Have We Come? Microorganisms. 2013 Sep 5;1(1):3-25. doi: 10.3390/microorganisms1010003. PMID: 27694761; PMCID: PMC5029497.