Download Bioluminescence

Bioluminescence
Jack Prehatny
Abstract
Adaptations and uses in animals
Red tide events
Bioluminescence and human use
Bioluminescence is the production of light by a living organism. Both
terrestrial and marine animals exhibit bioluminescence, but it is found
more commonly in marine animals. Bioluminescence can be observed in
several different phyla of marine organisms, many of which exist in the
pelagic and benthic zones of the ocean. The light these organisms produce
is synthesized rather than just a reflection or absorption of natural light,
and serves many functions. Bioluminescence and its causes have been
shrouded in mystery throughout history, with many accounts being linked
to paranormal activity. Today, scientists have a greater understanding of the
function, and it is even used in some medical tools and procedures today. It
is likely that bioluminescence will continue to be used by humans in
several practices in the future.
The phenomena of Bioluminescence in marine organisms is an adaptation
that serves many purposes. Common functions of these mechanisms
include predation, elusion, and attracting a mate. Certain adaptations allow
for different organisms to serve a function more efficiently. An example of
a defensive adaptation would be that of a squid, which uses its flashing
lights to disorient predators while it makes its escape. Another defensive
tactic that many fish use is called counter illumination. Many pelagic fish
fall victim to predators who hunt from below their prey, but with counter
illumination, many of these fish are actually safe. Bioluminescent organs
are positioned downwards, and mimic the light levels that strike the
topside of these fish, thus creating a transparent effect that helps
camouflage them in these pelagic zones. Another method used mainly by
starfish is a diversion tactic in which the starfish will detach a glowing
limb to draw predators away to make an escape. Sea cucumbers also use
the diversion tactic by attempting to attach their glowing particles and
detachable parts to nearby fish which act as a lure for predators.
A red tide event is a phenomena where large quantities of marine
microorganisms (Dinoflagellates) accumulate, forming what’s known as
an algal bloom, which is a reddish-brown in color. The rapid accumulation
of these Dinoflagellates result in heavy surface water coloration and
toxification of the surrounding ecosystem. These events are associated
with the term “Harmful Algae Bloom” since they pose a threat to marine
organism, the marine ecology, and humans. Densely packed, these groups
of microorganisms also deoxygenize the affected water, resulting in
oxygen levels so low that fish and other marine life die. Red tides occur
most frequently between the months of April and August in warmer water
where there is plenty of sunlight. Although there are many harmful effects
of these algal blooms, there are also benefits for marine ecology. These
organisms contribute to a high level of productivity in the Carbon-DioxideOxygen cycle. Carbon-Dioxide from the atmosphere diffuses into the
water where it is converted into oxygen by these microorganism, which
then diffuses back out into the atmosphere.
Humans have discovered several uses for bioluminescence in manmade
machines, tools, and medical procedures. One such example would be the
implementation of bioluminescence as a means of medical imaging. This
process, called “Bioluminescent imaging” permits noninvasive imaging
of internal biological functions, which may be used to gather a greater
understanding of diseases as well as the effect of treatments for these
diseases on these biological functions.
Chemistry
The light in Bioluminescence is created through a chemical reaction that
utilizes the light producing organic molecule luciferin, and the catalyst
luciferase. Fish, bacteria, and dinoflagellates use luciferase to catalyze the
oxidation of luciferin. Oxygen reacts with the luciferin to create
“oxyluciferin” which emits light energy. Luciferin is mainly introduced
into the system via diet, or is produced via internal synthesis.
Fig.8, GFP is used to “tag” cancer cells in an MRI.
Fig.3, Bioluminescent smoke being used as a defense mechanism.
Fig.1, Luciferase catalyzes the oxidation of Luciferin
Other marine animals, such as shrimp, cnidarians, and ctenophores use a
similar process that is slightly altered. Instead of catalyzing the oxidation
of luciferin, luciferase is bound to both oxygen as well as luciferin,
forming a “photoprotein”. Chemical ions such as calcium and potassium
are then added to the bond, creating a chemical reaction which emits light.
Other species have flashing lights that are exhausted after the luciferin
completes the oxidization process.
Although Bioluminescence is commonly mistaken for Phosphorescence or
Fluorescence, they are entirely different processes. Fluorescent light is
created by absorbing and converting light into different photons, whereas
bioluminescence is a chemiluminescent process in which a chemical
reaction takes place to synthesize it’s own light source. Phosphorescence is
similar to Fluorescence in that it absorbs light photons, but excites
electrons in the surrounding outer shell, producing a different light effect.
There are also many predatory adaptations for bioluminescence,
particularly in benthic fish. One such example exists in Anglerfish, which
have a long rod-like structure on their head, known as a filament. These
fish light up the tips of these filaments which act as a lure for curious and
unsuspecting prey. Other fish have the ability to create different colored
light to give them an advantage while hunting for prey. These fish use red
light, which many fish at the benthic level cannot detect because the
wavelength of red light is the longest, and thus permeates water the least.
Many fish are not adapted to see using red light, which is why these
predatory fish can use red light to seek out prey while remaining
undetected. Is has been suggested that a select few organisms mimic the
bioluminescent pattern “mating call” to lure in prey. What’s more is that
the color of bioluminescence varies among fish and smaller organisms
throughout the marine ecosystem. In defensive and territorial cases, light
frequencies of colors can be mimicked to startle predators or evict other
organisms from a desired location.
At night, the disturbance of these Dinoflagellates and other
microorganisms can cause a Bioluminescent glow. Different types of
luminescence can be linked to different types of microorganisms. In most
cases, Dinoflagellates are accompanied by phytoplankton such as diatoms,
which cause a bright fluorescent glow. Dinoflagellates accompanied by
non-photosynthesizing zooplankton produce a dimmer glow.
Bioluminescent adaptations also act as a means of communication for
mating purposes. Photophores on the sides and bottoms of many pelagic
and benthic fish help serve as a distinction from other bioluminescent
creatures, particularly when there are unique patterns on the head and tail.
These lighting patterns can be used for specified tasks such as mating
“calls” and signals. Furthermore, many of these fish have adapted to detect
certain colors in bioluminescence to distinguish from predators, prey, and
mates. Lanternfish are adapted to view blue-green light, while other
predators have adapted to using red light as a communication distinction.
Green Fluorescent Protein – (GFP), is used in cloning procedures for
conceivable plants and animals in labs everywhere. This protein can be
implemented into organisms to observe the creation and transport of other
proteins. Once the GFP gene is joined with those of other proteins, medical
equipment can be used to find the GDP distinct green luminescence and
track it. Today, it is commonly referred to as a “Biomarker”.
References cited
“Bioluminescence”. National Geographic. Web. 7 December, 2014.
http://education.nationalgeographic.com/education/encyclopedia/biolumin
escence/?ar_a=1
Fig.6, Dinoflagellates emit bioluminescence when stimulated
Fig.4, An anglerfish illuminates its filament to lure in prey.
Fig.2, Bioluminescence is created through chemical excitation whereas
Fluorescence uses excited light energy to absorb and emit photons.
Fig.5, Accumulations of Dinoflagellates form red tides
Special tools have been created that utilize bioluminescence in a plethora
of ways. One particular tool, known as a BioScan, can detect varying
levels of ATP in certain elements, which is essential in the production of
light. The use for this particular tool is to detect contaminations in water,
and ATP is an indicator for bacteria.
Milky seas are a phenomena where thousands of square miles worth of
seawater is filled with bioluminescent bacteria (Vibrio harveyi), resulting
in a bluish glow at night. These eerie events have been recorded
throughout history and have often been associated with paranormal activity
and ghost stories from sailors. From satellite images, milky seas appear
whitish blue in color, with the largest ever recorded being the size of the
state of Connecticut.
Haddock, S.H.D., M.A. Moline, and J.F. Case. “Functions of
Bioluminescence”. Web. 2010. http://biolum.eemb.ucsb.edu/functions.html
http://guides.library.harvard.edu/content.php?pid=419040&sid=3493509
“Bioluminescence at work today”. Harvard University. Web. 14 August,
2014.
Bruckner, Monica. “Red Tide- A Harmful Algal Bloom”. Montana State
University. Web. 7 December, 2014.
http://serc.carleton.edu/microbelife/topics/redtide/index.html
Litteral, Linda. “Bioluminescence in marine animals”. Dive Training
magazine. Magazine. 5 May, 2013.
http://dtmag.com/Stories/Ocean%20Science/01-98-ecoseas.htm
J.W. Hastings. “Chemistry of Bioluminescence”. University of Santa
Barbara. 24 November, 2014. Web. http://biolum.eemb.ucsb.edu/chem/
Fig.7, Satellite photo of a large “Milky Sea”.
“What is Bioluminescence?”. National Ocean and Atmospheric
Administration. 7 August, 2014. Web.
http://oceanservice.noaa.gov/facts/biolum.html