coral and photosynthetic dinoflagellates are one of nature ’s heavy symbiotic achiever stories , combining to make the bedazzle reefs that host the greatest concentration of the world ’s metal money . Yet one crucial vista of their relationship has always been a mystery story – how do they obtain each other ? The answer may save dying reefs .

Although red coral get some energy from catching plankton , most of what they need to go is issue by members of the genusSymbiodinium , which also provide the gorgeous colors that make coral reefs such a joy to human center . When try , coral rout out their dinoflagellates , but they die after too long without nourishment .

For all the inquiry on what causes coral and dinoflagellates to part style , slight thoughtfulness has been given to how they get along together in the first place . How do the single - celled organism tramp across a reef find the coral that will become their home until heat focus do them part?Professor Jun Minagawaof Japan ’s National Institute for Basic Biology investigated a theory that the corals ' glow lights the way home .

Like Portuguese man-of-war and a range of other invertebrates , red coral produce a protein that glows green after picture to shorter wavelength light . With great flair for language , biologists name this " gullible fluorescent protein " ( GFP ) , and turn it into aninvaluable toolfor transmissible research .

Minagawa collected free - livingSymbiodiniumand exposed them to dissimilar colors of light . InProceedings of the National Academy of Sciences , he reports thatSymbiodiniumare attracted to dark-green light and force back by blasphemous and violet wavelengths . When the container were clear up with blue light , causing the live red coral to shine green and   the dead one to shine blue , 10 times as manySymbiodiniumwere detect in the locality of the living coral than around the dead ones .

Convincing as this is , Minagawa conducted a further assay to verify some other factor was not contort the resultant role . A resin phonograph record coated with fluorescent dye that released sparkle with a peak wavelength just 1   nanometer higher than the GFP was also find to attractSymbiodinium . Again this was only when the dye ’s fluorescence was make with inadequate wavelength Christ Within .

The attraction to green wavelength allowsSynbiodiniumto find corals on the reef , and the repulsion from juicy light prevents them being perturb by sun ( which contains both   green and blue light ) , although the writer think it ab initio evolved for other reasons .

The paper also suggests GFP may be necessary for coral that have expelled theirSynbiodiniumto recruit more , if the reference of their stress is removed before they exit . Hopefully , this cognition can be practice for reef restitution .