Have you seen the ocean glow at night?
Have you possibly been on a boat and seen the wake glow as you pass through?
These little creatures that light up the night are improperly identified as Phosphorescents, but they are really Bioluminescent Dinoflagellates, a type of marine plankton.
Plankton are free-floating ocean drifters, which can be plants, animals or bacteria. The Dinoflagellates use sunlight in the same way that land plants photosynthesize, in order to produce food for themselves. Photosynthesis is also a key part in the illumination process of the Dinoflagellate and the term “bioluminescence” means the creation of light by a living organism.
As the waters in our South Carolina summer become warmer, these Dinoflagellates reproduce and increase in number.
This plankton is a very valuable food source for oceanic filter feeders and even other types of plankton. Small fish, aquatic larvae and small crustaceans need these Dinoflagellates to survive. Through the food chain, they are important in nourishing all of the fish, shellfish and mammals in our oceans.
Not only are Dinoflagellates important for our food chain and pretty to look at, they also play a very important role in creating oxygen for our Earth. Since they are plants that photosynthesize, they take water and carbon dioxide to create food for themselves. As a byproduct of their food creation, they release oxygen into the air and into the water.
The Bioluminescent Dinoflagellates use their glow as a form of protection.
They can feel vibrations in the water as predators come near them. As a response, they light up in order to attract larger secondary predators towards the primary creature coming to eat them. The illumination can draw attention to larger predators from a great distance in the water, thus scaring the primary predator away from the Dinoflagellates.
Although we as humans are not predators to the Dinoflagellates, we disturb the water around them, which makes them illuminate. Another common place to see the Dinoflagellates is in the crashing waves at night. As the little plankton are washed ashore, they are definitely being disturbed, which creates the glowing surf.
Their glow is strongest after several hours of darkness. As the sun is setting, you will still be able to see them but they will not be as bright. As the night wears into the early morning, their glow also becomes more dim. They are able to recharge once the sun rises and the new day begins. The light emitted by a Dinoflagellate can last for 0.1 to 0.5 seconds.
There are many different types of bioluminescent creatures in the ocean.
Some examples on our Atlantic coast are bioluminescent comb jellyfish, angler fish and certain types of shrimp. The light emitted by these creatures is created by a chemical reaction. This reaction is energy being released by the organism. Every living cell creates some form of bioluminescence, however, most of these illuminations cannot be seen by the naked eye. Ever hear of a person’s aura? These illuminations can be in many different colors; sea creatures’ bioluminescence is generally within the spectrum of greens, blues and reds.
By Master Naturalist Kathleen McMenamin
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