"I really wish I could get my corals to fluoresce"
There is a statement I hear on a regular basis. However I
think most people really mean to say "I wish I could see my
corals fluorescing". Many corals we keep in the aquarium hobby
are capable of fluorescing. In fact many corals in your aquarium
are fluorescing right now. In order to see this phenomenon,
we must first understand how it works.
Fluorescence Overview
Fluorescence is a process whereby a matter of energy is absorbed
by a substance, and then released by that substance with less
energy. In this case a light source of high energy (lets say
blue light) is absorbed by a substance (a coral) and then released
with less energy (i.e. green light or red light). In general
four pigments are observed in coral fluorescence (Mazel 1997).
Dr. Charles Mazel the world authority in coral fluorescence
simply states that "fluorescence is magic". To the scientist,
that just may be the case.
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Purpose
The purpose of this study was not to explain why some corals
fluoresce, or how many, or how often. What we are exploring
here is the process of fluorescence and showing examples of
this amazing process. This is the first step in a series of
projects comparing captive coral fluorescence with the fluorescent
properties of natural coral reef systems. Natural coral reef
systems contain corals and coral skeletons which fluoresce.
These coral tend to have more fluorescent pigments closer to
mainland and is also directly related to the amount of nutrients
in the water (Scoffin et al, 1989)
Seeing Fluorescence
In order to see fluorescence (with any item, not just marine
life) it requires a few important items. First of all you need
to have a high energy source to react with the substance. In
this case a very high intensity blue light (actinic light)
is shown. This high energy source is called the "exciter" which
is the source for "excitation light". The second item you need
is a filtering system that blocks the excess light, allowing
you to only see the fluorescent light. This filter is a "barrier
filter" which allows you to see the "emission light" from the
fluorescent substance. The third item you need is the actual
fluorescent item. Here we are looking at corals, but all sorts
of items in your house will fluoresce, including plastic toys,
honey, refrigerator magnets, peanut butter, etc. Why any of
these items fluoresce is truly a mystery.
Corals That Will Fluoresce
The following are but a few examples of corals that will
fluoresce in the aquarium.
Now by increasing the amount of high energy light the corals
receive, we can increase the amount of light they release through
fluorescence.
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With the help of a filter system, we can remove the excess
high energy light, and be left seeing (and thankfully photographing)
the fluorescent light emitted from the corals.
Conclusion
While very little is known regarding coral fluorescence, one
thing is for sure, many corals will and do fluoresce. Whether
fluorescing is related to coral health, spawning cycle, defensive
ploys, or aggressive ploys, is completely unknown. From a hobbyist
perspective the attractiveness of many corals is directly related
to the coloration of the corals. For this example, corals can
have their color greatly enhanced by fluorescent effects….
even if you don't see it.
Acknowledgements
I would like to thank Dr. Charles Mazel for his incredible
contributions to the fluorescent marine life field. His research
and presentations are cutting edge, and bring new science directly
to the hobbyists. This project is also indebted to the financial
support of The Aquatic & Terrestrial Research Team, Shane
Silcox, and a generous grant from PADI Project Aware. Project
Aware has demonstrated a commitment to coral reef studies with
their sponsorship of this venture. On a personal note the photographic
experience and generous friendship of Shane Silcox proved to
be instrumental in the completion of this project.
Author Information
Adam Blundell M.S. works in Marine Ecology, and in Pathology
for the University of Utah. While not in the lab he is the
president of one of the Nation's largest hobbyist clubs, the
Wasatch Marine Aquarium Society (www.utahreefs.com). He is also Director of The
Aquatic & Terrestrial Research Team, a group which utilizes
research projects to bring together hobbyists and scientists.
His vision is to see this type of collaboration lead to further
advancements in aquarium husbandry. Adam has earned a BS in
Marine Biology and an MS in the Natural Resource and Health
fields. Adam can be found at adamblundell@hotmail.com.
References
Mazel, C.H., (1997), "Coral fluorescence characteristics:
excitation/emission spectra, fluorescence efficiencies, and
contribution to apparent reflectance", International
Society for Optical Engineering, Massachusetts, USA.
Scoffin, T.P., Brown, B.E., Tudhope, A.W., (1989), "Fluorescent
and Skeletal Density Branding in Porites-Lutea from Papua
New Guinea and Indonesia", Coral Reefs 7(4): 169-178,
Edinburgh, Scotland.
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