Bacteria Give Coral an Orange Glow
This story entered on 4th Oct, 2004 05:53:04 AM PST
NURP-sponsored research published in Science
article has contributed to the discovery that cyanobacteria are
responsible for the orange glow emitted from Montastraea cavernosa.
The great star coral M. cavernosa occurs in a diverse array
of colors because it possesses genes that code for cyan, red, and
green fluorescent proteins. However, M. cavernosa can also
emit an orange glow, which does not originate from the coral. The
orange glow is emitted from symbiotic cyanobacteria, a photosynthetic
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The study results suggest that cyanobacteria, which reside in M.
cavernosa's epithelial cells, absorbs light energy and transforms
it to a red-orange hue that fluoresces as an orange glow due to
the weak energy coupling of red and orange pigments within cyanobacteria.
The research, led by Michael Lesser from the University of New Hampshire
and supported by NURP's Caribbean Marine Research Center, also suggests
that cyanobacteria has a symbiotic relationship with its coral host;
the cyanobacteria provides an important service for it's host by
releasing nitrogenase, an enzyme which converts the nitrogen found
in seawater to a form usable by the coral.
Cyanobacteria may also provide a usable form of nitrogen to zooxanthellae,
which provides M. cavernosa with its carbon requirements.
In addition, zooxanthellae may also supply carbon to cyanobacteria,
suggesting a symbiotic relationship between the two organisms. The
presence of cyanobacteria in corals highlights the important role
that symbiotic relationships can potentially play in species diverse
coral reefs and adds another level of complexity to the ecology
and biology of corals.
The study is published in Science (see citation below) and
was featured on MSNBC and the BBC.
Michael P. Lesser, Charles H Mazel, Maxim Y. Gorbunov, Paul G. Falkowski
(2004). Discovery of Symbiotic Nitrogen-Fixing Cyanobacteria in
Corals. Science. Vol. 305, Aug 13, 2004, pp. 997 - 1000.
Name: John Marr
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