Due to copyright restrictions from the photographer, I am restricted to images no greater than 40 pixels so I hope you have a magnifying glass handy !.This information resulted from a May weekend paddle in 1999 at Ardgartan campsite, during which the weather was unseasonally hot and sunny with no wind at all. A chance stoneskiff at dusk decided myself and Alan Fletcher should do a midnight paddle to get the most from what we thought might be "phosphorescence".
The effect was staggering, in zero light conditions where Alan was nigh on invisible, the radiance from the paddle blades as the water spilled from them was dazzling. The bright light green glow from his hull as the friction against the water upset the algy showed his position from several hundred feet as he paddled along.
The next night Morag and Pamela (our respective spouses) took to the water amid "gosh" "Waow" and other such squeaks, thoroughly enjoying the experience. These conditions were absolutely ideal for this phenomenon what with scorching sunlight and NO wind. The location of the campsite, hidden from Arrochar and Ardgarten by a spit of land, meant total darkness. Fully charged algae and ideal conditions for viewing their partypiece. A sight and a site, we shall always remember.
Bioluminescence is simply light produced by a chemical reaction which originates in an organism.
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Bioluminescence, where a light-producing chemical reaction occurs inside an organism (Dinoflagellates), is a form of chemiluminescence.
Dinoflagellates are microscopic, (usually) unicellular, flagellated, often photosynthetic protists, "algae" to you and I.
The luminescence of a single dinoflagellate is readily visible to the dark adapted human eye. Most dinoflagellates emit about 6 x 108 photons in a flash lasting only about 0.1 second. Much larger organisms such as jellyfish emit about 2 x 1011 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, i.e. The brighter the sunlight, the brighter the flash.
The effect can be expected anytime and in any region or depth in the sea. They (Dinoflagellates) are mechanically excited to produce light by a ship's passage or even by the movement of porpoises and smaller fish. It's most common occurrence to the sailor is in the often brilliantly luminescent bow wave or wake of a surface ship. In these instances the causal organisms are almost always dinoflagellates, single-cell algae, often numbering many hundreds per liter.
Bioluminescence is a primarily marine phenomenon. It is the only source of light in the largest fraction of the habitable volume of the earth, the deep ocean. 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.
Bioluminescent bacteria occur nearly everywhere, and probably most spectacularly as the rare "milky sea" phenomenon, particularly in the Indian Ocean where mariners report steaming for hours through a sea glowing with a soft white light as far as the eye can see.
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- MYTH :
- Bioluminescence is mostly caused by bacteria.
- FACT :
- Bacteria can be luminous, and some organisms like fish and squid do have bacteria in their light organs. However, by far the majority of animals are able to produce light with chemicals that they have stored in their bodies.
- MYTH :
- Bioluminescence is the same as "fluorescence" (or "phosphorescence", or "chemiluminescence").
- FACT :
- All of the terms apply to the production of light from chemicals, but bioluminescence is only similar to chemiluminescence.
Phosphorescence is similar to fluorescence except that the excited product is more stable, so that the time until the energy is released is much longer, resulting in a glow after the light has been removed. This is the basis behind glow-in-the-dark stickers or watch faces.
Some organisms emit light continuously, but most emit flashes of durations ranging from about 0.1s to 10s. Some dinoflagellates can respond repetitively to excitation over a short period. In single cell organisms like dinoflagellates or radiolarians luminescence is triggered by deformation of the cell surface by minute forces (Shaking your hand in the water). Mechanical deformation causes an action potential sweeping over the vacuole membrane and this is thought to induce light emission by admitting protons from the acidic vacuole into contact with the cellular elements that contain the light emission chemistry. (In other words, there are two linings within the outer cell wall which, when touching together by being pressed together, allow the light emitting chemistry to occur)
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They form a significant part of primary planktonic production in both oceans and lakes. Most dinoflagellates go through moderately complex life cycles involving several steps, both sexual and asexual.
Besides being important primary producers, and therefore an important part of the food chain, dinoflagellates are also known for producing nasty toxins, particularly when they occur in large numbers, called "red tides" because the cells are so abundant they make the water change colour.
Besides being bad for a large range of marine life, red tides can also introduce non-fatal or fatal amounts of toxins into animals (particularly shellfish) that may be eaten by humans, who are also affected by the toxins. (Hence the scare about eating shellfish from the Forth estuary a couple of years ago) Many of these toxins are quite potent, and if not fatal, can still cause neurological and all sorts of other nasty effects. Add this to the rather ominous suspicion that red tides may be more common thanks to human inputs of phosphates and warmer global temperatures, and you can probably see why we have a vested interest in finding out more about them - both medical and economic.
They need to provide themselves with an appropriate amount of light on a regular basis because the only way they can grow is by producing their own food using a process called photosynthesis, just like plants do. They can grow in sunlight or artificial light as long as it's fairly bright but not too hot. As far as temperature, they need to be kept in an area that doesn't get too hot or too cold
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Dinoflagellates have a circadian rhythm which controls their bioluminescence and photosynthesis on a 24-hour basis, i.e. they only photosynthesize when they "think" it's day and they only produce bioluminescence or flash when they "think" it's night. So, they grow on a strict light schedule, otherwise their natural rhythms can't synchronize with the light cycle and they won't know when to flash and when not to flash.
Ideally, they should get 12 hours of light and 12 hours of darkness every 24 hours and at the same time every day. If this happens, the dinos will be brightly luminescent whenever they are in their "night phase" and they will be pretty much non-luminescent when they are in their "day phase". (This is why the effect was so pronounced during our stay - Brilliant sunlight by day and clear dark skies coupled with prolonged calm seas to minimise the cell wall deformation by the action of waves)
If you are doing experiments with these organisms remember that these rhythms will determine when you should perform the experiments. You should test their bioluminescence at the same time every night so you know that the organism is at the same point in its natural rhythm each time.
In a similar fashion to the way we perceive being touched, this is the type of stimulation that causes a dinoflagellate to produce a flash of light. Dinos are highly sensitive to anything that pushes on their cell wall, even the seawater they live in can cause them to flash if it becomes very rough and stirred up, the water becoming very turbulent and pushing on their cell walls causing them to flash.
Currently, scientists are using the bioluminescence a dinoflagellate produces as an assay for detrimental effects caused by pollution in various marine environments. The bioluminescence that a dinoflagellate can produce reflects how healthy it is.
I hope you found this information interesting and I apologise for the rather technical nature of some of it. I found the information for this page amid scientific information web sites for reading by scientists who do rather like to attach jargon to all their work. It doesn't help Joe Public unless a dictionary is to hand. !
This page cannot end properly without a special thanks and SORRY to the other campers who had to tolerate two canoeists falling over a perimeter fence at later than 1am in their struggle to get 2 sea kayaks back to the cars in total darkness. Thanks for not using barbed wire on the fences !
There is certainly more info out there on this subject but hopefully this will whet your appetite about a fascinating subject right on your doorstep (at midnight !)
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Due to copyright restrictions from the photographer, I am restricted to images no greater than 40 pixels so I hope you have a magnifying glass handy !.
To see the spectacular photography of these bugs in better detail, and with more accurate explanations, Click Here to go to the "Bioluminescence Web Page"