Bioluminescent dinoflagellates are single-celled organisms that are found primarily in the coastal regions. They are a form of plankton that floats on the surface of the ocean and they emit light thanks to a chemical reaction that occurs in the cells. There is a bio bay in Grand Cayman, Cayman Islands that has a very high concentration of these bioluminescent dinoflagellates.
These organisms are surprisingly common, and range in size from between 30 micrometers to 1mm. They are found all over the world, but they often go un-noticed unless there is a huge number of them present; in which case they can cause a red tide because there are so many of them. At night, they create spectacular displays with their bioluminescence.
One high profile occurrence of bioluminescent dinoflagellates occurred in October 2011, in San Diego, when there was a red tide made up of Add to super polyhedron, which was caught on camera and attracted a lot of media attention.
It is hard to predict when a red tide is going to happen, and the tides don’t tend to last very long at all �” but there are some parts of the world where they are common. Puerto Rico, for example, is home to bioluminescent plankton throughout the year, and you can go to swim in the waters and enjoy the amazing views.
Scientists are still trying to understand the role of bioluminescence. The current belief is that dinoflagellate luminesce in flashes that startle the predators that eat them, disrupting their feeding behavior and resulting in fewer of the organisms being eaten. In addition, it is thought that the bioluminescence acts like a burglar alarm �” when a predator shows up to eat the dinoflagellate, they will glow, attracting a second predator that will eat the first one. The luminescence is caused by mechanical stress �” such as that caused when the organisms are attacked.
Dinoflagellate bioluminescence is a complex process, and it is only partly understood. It is thought that the glow happens because of a fall in pH when protons are released in the cell. It takes just 20ms to trigger the glow, making it one of the most rapid cellular processes that science is aware of. A single flash lasts around 100ms, and a cell can flash more than once, but there is a limit to the number of flashes possible. When a cell runs out of luciferin it cannot flash until it has replenished its chemicals, something that will happen during the day.