Advantage for Brain corals & Co.
A new study has shown that "robust" reef-building corals are the only known organisms in the animal kingdom that produce one of the "essential" amino acids. This makes them less vulnerable to global warming than other corals.
Under the direction of dr. Hua (Emily) Ying of the Australian National University (ANU) and Prof. David Miller of the ARC Center of Excellence for Coral Reef Studies (Coral CoE) at the James Cook University (JCU), a team of researchers using genomic techniques has found that the a "robust" coral group, which includes a number of brain corals, has a distinct physiological advantage compared to "complex" corals, including common, branched corals, such as staghorn corals (Acropora).
"Amino acids are the building blocks of life, they are critical in, for example, the repair of tissue or the formation of new tissue, but the extraction of amino acids is energetically expensive for animals, so they typically produce only 11 out of 20 vital ones.", so the Dr. Emily Ying, lead author of the study, recently published in the journal Genome Biology. "The remaining nine amino acids are called 'essential' amino acids because they have to be fed through the diet, which are tiny animals known as zooplankton for corals."
But this is not the only form of coral nutrition. By having a mutually beneficial relationship with microalgae, with which the corals live in symbiosis, they are supplied with the energy they need to build their skeletons.
"The algae also provide the coral with some of the 'essential' amino acids, making them less dependent on their diet than other animals," adds co-author Prof. David Miller.
For example, when global warming causes coral bleaching, they lose the microalgae they live in symbiosis with and are suddenly completely dependent on their diet to meet their nutritional needs.
"We now know that 'robust' corals can produce at least one of the 'essential' amino acids without relying on the microalgae, suggesting that they might be more resistant to bleaching than 'complex' corals at least in the short term branched antler corals," explained Prof. Miller.
"Our research also suggests that 'robust' corals are less selective about which types of microalgae can colonize coral tissue, and the ability to accommodate a wider range of microalgae species could allow for faster adaptation to higher temperatures," says Prof Miller.