Fluorescence of corals commonly found in mesophotic reefs of the Red Sea.
Credit: Jörg Wiedenmann
Glowing corals that display a surprising
array of colours have been discovered in the deep water reefs of the Red
Sea by scientists from the University of Southampton, UK, Tel Aviv
University and the Interuniversity Institute for Marine Sciences (IUI),
Israel, together with an international team of researchers.
The researchers, whose findings have been published online today in research journal PLOS ONE, hope that some of the coral pigments could be developed into new imaging tools for medical applications.
The team studied corals at depths of more than 50 metres and found
that many of them glow brightly with fluorescent colours, ranging from
green over yellow to red. The encounter of such a rainbow of coral
colours in deep waters was unexpected, since their shallow-water
counterparts in the same reef contain only green fluorescent pigments.
Jörg Wiedenmann, Professor of Biological Oceanography and Head of the
University of Southampton's Coral Reef Laboratory, explains: "These
fluorescent pigments are proteins. When they are illuminated with blue
or ultraviolet light, they give back light of longer wavelengths, such
as reds or greens.
"Their optical properties potentially make them important tools for
biomedical imaging applications, as their fluorescent glow can be used
to highlight living cells or cellular structures of interest under the
microscope. They could also be applied to track cancer cells or as tools
to screen for new drugs."
Gal Eyal, PhD candidate at the IUI, says: "Corals from these
so-called mesophotic reefs are less well studied since they are beyond
the depth limits of standard Scuba diving techniques. Advances in
technical diving have enabled us to explore coral communities from these
deeper waters.
"Since only the blue parts of the sunlight penetrate to depths
greater than 50 metres, we were not expecting to see any red coloration
around. To our surprise, we found a number of corals showing an intense
green or orange glow. This could only be due to the presence of
fluorescent pigments."
Such pigments are often found in shallow water corals, where they can
act as sunscreens for the corals and their symbiotic algae. Finding
them in depths where corals are struggling to collect enough light to
sustain the photosynthesis of their algal symbionts (a vital energy
source for the corals) is therefore unexpected.
Dr Cecilia D'Angelo, Senior Research Fellow at Southampton, has
studied corals commonly found in mesophotic depths in the experimental
aquarium of the University's Coral Reef Laboratory: "In many shallow
water corals, the production of the pigments is tightly controlled by
the amount and colour of the incidental light. In the majority of our
deep water species, the pigment production is essentially independent
from the light exposure of the coral animals.
"We found, however, that some of the pigments of these corals require
violet light to switch from their nascent green colour to the red hue
of the mature pigment. This is a particularly interesting property to
develop markers for advanced microscopic imaging applications."
The team now are now exploring which other biological functions these fluorescent pigments may fulfil.
Substantial parts of the research were conducted during the
International Mesophotic Workshop 2014 held at the IUI in Eilat. Dr
Yossi Loya, Professor of Zoology at Tel Aviv University and organiser of
the workshop, concludes: "This study clearly shows the potential of
interdisciplinary and international collaborations. We are delighted
that the workshop has opened up such exiting new research avenues."
Story Source:
The above post is reprinted from
materials provided by
University of Southampton.
Note: Materials may be edited for content and length.