above: this is an actual photograph of a dinoflagellete that has been enhanced to add the color and glow, the actual light burst would be considerably bigger than this in relationship to the dinoflagellate.

What makes a Biobay?

The Bioluminescent Bay in Vieques is, perhaps, the brightest in the world! with over 750,000 tiny dinoflagellates per gallon of water that light up when they are touched! Imagine a lake full of Tinkerbells fairy dust! Pure magic, the experience is actually indescribable.

The bioluminescent dinoflagellates Pyrodinium bahamense are a photosynthesis using plankton. They are one celled and measure about 1/500 th of an inch. The tiny burst of light it gives off is a hundred times bigger than itself. ( Above is merely an artists depiction of the glow) Each dinoflagellete bursts into light when it feels pressure against its cell wall. The light is given off in an instantaneous process; when you add the light bursts of 750,000 dinoflagellates per cubic foot of water together the effect is spectacular!

Almost all marine bioluminescence is (greenish) blue in color, for two related reasons. First, blue-green light (wavelength around 470 nm) transmits furthest in water. The reason that underwater photos usually look blue is because red light is quickly absorbed as you descend. The second reason for bioluminescence to be blue is that most organisms are sensitive only to blue light.

The luminescence of a single dinoflagellate is readily visible to the dark adapted human eye. Most dinoflagellates emit about 6e8 photons in a flash lasting only about 0.1 second. Much larger organisms such as jellyfish emit about 2e11 photons per second for sometimes tens of seconds. The intensity of luminescence by photosynthetic dinoflagellates is strongly influenced by the intensity of sunlight the previous day. The brighter the sunlight the brighter the flash.

Columbia Encyclopedia: Bioluminescence is production of light by living organisms. Organisms that are bioluminescent include certain fungi and bacteria that emit light continuously. The dinoflagellates, a group of marine algae, produce light only when disturbed. Bioluminescent animals include such organisms as ctenophores, annelid worms, mollusks, insects such as fireflies, and fish. The production of light in bioluminescent organisms results from the conversion of chemical energy to light energy. In fireflies, one type of a group of substances known collectively as luciferin combines with oxygen to form an oxyluciferin in an excited state, which quickly decays, emitting light as it does. The reaction is mediated by an enzyme, luciferase, which is normally bound to ATP (see adenosine triphosphate) in an inactive form. When the signal for the specialized bioluminescent cells to flash is received, the luciferase is liberated from the ATP, causes the luciferin to oxidize, and then somehow recombines with ATP. Different organisms produce different bioluminescent substances. Bioluminescent fish are common in ocean depths; the light probably aids in species recognition in the darkness. Other animals seem to use luminescence in courtship and mating and to divert predators or attract prey.

The chemical reaction responsible for the production of light bursts begins with a luciferin, a light emitter. This chemical is either acquired through the food chain or synthesized within the organism itself. Different types of organisms use different luciferins for their reactions. There are believed to be about six different types of luciferin molecules. The luciferin reacts with another chemical, called the luciferase, salt and oxygen resulting in a burst of light and water.

Luciferin + Luciferase + Oxygen + Salt ----> Light + Water

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 .

In contrast, bioluminescence is essentially absent (with a few exceptions) in fresh water, even in Lake Baikal. On land it is most commonly seen in the few families of luminous insects.

Bioluminescence has evolved many times in the sea as evidenced by the several distinct chemical mechanisms by which light is emitted and the large number of only distantly related taxonomic groups that have many bioluminescent members.

More complete Vieques Biobay info on my Golden Heron Ecotours website

For unique, actual photographs of the bio bay. ( Which, ironically, don't really show what it is like... as they are time exposures by necessity) go to the National Geographic article about the biobay. Here is a website with good information about Bioluminescence • Problems with light pollution• The Vieques Conservation and Historical Trust works to study and protect the biobay. They also have aquariums with many fish and various sea creatures to see.