2005-11-11 / Columnists

Drawing On Science


by Stephen Yaeger

The article about our local ocean waters exhibiting some kind of glowing effect in The Wave’s October 28 edition caught my interest. The first thing that came, laughingly, to mind was TV’s new series “Invasion” about glowing something-or-others that reside in local waters…they take over or replace, it seems, the locals.

Could our glowing waters be the result of such things?

Unknown creatures from the deep?

Perhaps aliens?

A government conspiracy?

Godzilla?

Nah! I knew what it was: bioluminescence. The word comes from the Greek bios (= living) and the Latin lumen (= light) and means “living light.” It is the chemical production and release of light energy by a living organism and is primarily a marine phenomenon. The reaction involves a substrate called luciferin and an enzyme, luciferase . When oxygen and ATP, an energy storage molecule, is added energy is released.

Almost 100% of this energy is light.

There is, for the most part, no heat energy released.

Because of this bioluminescent light is known as “cold light.” An ordinary light bulb produces only 10% of its energy as light…the rest of the energy, 90%, is heat energy.

Marine bioluminescent organisms can be found on the surface as well as in the dark ocean depths.

The most common organisms exhibiting this light producing ability are the dinoflagellates, which are members of floating organisms known as photoplankton.

They may gather by the hundreds of thousands to produce the well-known red tides.

This is quite a feat since the largest dinoflagellate is about the size of the period at the end of this sentence. Typical dinoflagellates are shown in the diagram.

Bioluminescent phytoplankton is often stimulated into emitting light. This is a common sight among mariners when the bow wave (or wake) of their ships glow from the stimulated cells.

Breaking waves may also glow with a blue light giving an eerie appearance to the water. It is this glow that was obviously observed by those who saw the phenomenon.

I had an interesting experience with bioluminescence. It was many years ago when I was a pioneering/science counselor for a sleep-away camp. I had just finished telling the kids a scary story (really shook them up) about forest creatures called Woodins.

(My book, Ian and the Woodins was sort of based on them and, coincidently, bioluminescence plays a major role in the book.)

We were out in the woods and everyone was tucked away in their sleeping bags. Not long after we turned in, a number of the boys came over to me. They were obviously frightened. They told me that there was some animal staring at them. I got up and, sure enough, there were two glowing eyes, low to the ground, looking right at us! I slowly picked up my trusty flashlight, pointed it at the “animal” and flicked it on. Nothing, nada, not even an insect was there. When I flicked the light off there were the same glowing eyes staring at us again. After the third round of flicking on and off I walked over to the spot where the “eyes” were and there they were: two mushrooms that exhibited bioluminescence! I learned that “Jack O’ Lantern” and Honey mushrooms are among many organisms that have the ability. Fireflies, come centipedes, Anglerfish, and many jellyfish also produce cold light.

Actually all cells have the ability to produce some form of bioluminescence within the electromagnetic spectrum. Most of this light is neither visible nor apparent to our unaided eyes. Organisms that produce light by bioluminescence do so within a given wavelength of the spectrum. Also the duration, regularity and timing of the process is dependent on the organism producing the light.

There are basically three types of “cold light.” Internal luminescence is light produced by specialized cells within an organism known as photophores . External luminescence is produced by excretions (squids have this ability). Bacterial luminescence produced by bacteria just below or on the surface covering of organisms. Regardless of the source the chemical reaction is the same.

Why bioluminescence? Scientists believe there may be four explanations for organisms possessing this ability.

1. Camouflage: deep ocean creatures are often silhouetted against the surface light so they may use it to make themselves “invisible” to hunting eyes. The Bobtail squid and marine hatchetfish do this.

2. Attraction: using it as a lure to attract delicious prey. The anglerfish has a dangling, glowing appendage extending from its head to lure unsuspecting prey. Fireflies attract mates by flicking their light on and off.

3. Repulsion: some squids release bioluminescent mixtures to repel predators. Dinoglagellates flash for the same reason.

4. Communication: bioluminescence may play a role in communication between bacteria for colony formations.

So the next time you see a glow in the ocean waters it may be just phytoplankton, jellyfish, scared squid or………?

Questions/comments? E-mail

Steve:Drawingonscience@aol.com

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