Coral reefs of Terembu Raya overlooking Pulau Semakau.
Corals, it appears, have sophisticated systems of biological communication that are being stressed by global change.
Corals are only able to survive based on proper function of an intricate symbiotic relationship with algae that live within their bodies. The algae use the energy of the sun to conduct photosynthesis and produce sugars.
"Some of these algae that live within corals are amazingly productive, and in some cases give 95 percent of the sugars they produce to the coral to use for energy," Weis said. "In return the algae gain nitrogen, a limiting nutrient in the ocean, by feeding off the waste from the coral. It's a finely developed symbiotic relationship."
What scientists are learning, however, is that this relationship is also based on a delicate communication process from the algae to the coral, telling it that the algae belong there, and that everything is fine. Otherwise the corals would treat the algae as a parasite or invader and attempt to kill it.
"Even though the coral depends on the algae for much of its food, it may be largely unaware of its presence," Weis said. "We now believe that this is what's happening when the water warms or something else stresses the coral – the communication from the algae to the coral breaks down, the all-is-well message doesn't get through, the algae essentially comes out of hiding and faces an immune response from the coral."
This internal communication process, Weis said, is not unlike some of the biological processes found in humans and other animals.
Understanding this and other aspects of corals may help explain why coral reefs around the world are collapsing and what it will take for them to survive a gauntlet of climate change and ocean acidification.
Full article on the wildsingapore news blog.
