Compiled by BioPhotonics staff
AUSTIN, Texas – The color that young staghorn coral fluoresce – red or green – seems to predict
whether they will swim away from their reef of origin, or stay and settle, biologists
The Acropora millepora coral that fluoresce redder are less likely
to remain and develop into coral polyps than their greener peers, according to biologists
at the University of Texas. These findings may help scientists monitor how corals
adapt to global warming as they shift to cooler latitudes.
At left and below right: Example of fluorescence in the adult Acropora millepora coral.
The biologists crossed different color morphs of A. millepora
coral, exposing the offspring larvae to a settlement cue: ground-up calcareous red
algae. They found that the larvae that inherited a redder fluorescent color from
their parents were less likely than the green larvae to stay and metamorphose into
At left: Fluorescent photograph of two full-sibling young corals, three days after settlement and metamorphosis.
Images courtesy of Mikhail Matz and Joerg Wiedenmann, University of Texas at Austin.
Under the influence of global warming, this particular life history
trait of the larvae is expected to undergo a significant amount of evolution, said
Mikhail “Misha” Matz, assistant professor of biology at the university.
He says researchers expect to see the long-range dispersers, or redder coral, starting
to predominate as they shift to cooler latitudes.
At right: Fluorescence of Acropora millepora larvae, one of the greener
It is not clear whether the coral’s fluorescence and response
to settlement cues, which are both under genetic control, are functionally linked
in coral, or whether there’s simply a correlation. It’s possible that
fluorescence is related genetically to the capacity of larvae to sense the proximity
of a coral reef, and thus might have a direct correlation.
An example of color contrast between families. The top two panels depict larvae, while the bottom two panels show young
polyps just after metamorphosis.
Although the researchers do not yet understand the purpose of
fluorescence in coral, they believe their discovery has brought scientists a step
closer to determining its function in this sea creature.
The research is reported in Proceedings of the Royal Society B,
published online Jan. 26, 2011 (doi: 10.1098/rspb.2010. 2344).