Recently researchers have uncovered a gene in corals that responds to day/night cycles, which provides some tantalizing clues into how symbiotic corals work together with their plankton partners.
WHAT ARE CORALS?
Corals are fascinating animals in term that they form the largest biological constructions in the world. They exist as small sea anemone-like polyps, typically in colonies of many identical individuals. The group includes the important reef builders that are found in tropical oceans, which secrete calcium carbonate to form a hard skeleton.
Interesting fact about this is, that sprawling coral reefs cover less than 0.2 % of the seafloor yet provide habitats for more than 30% of marine life. In shallow waters that don't have abundant food, corals have developed a close relationship with small photosynthetic critters called dinoflagellates.
DINOFLAGELLATES
The Dinoflagellates are Photosynthetic Creatures that use sunlight to produce energy for the coral, which in turn use that energy to construct mineralized skeletons for protection. This mineral production is known as Coral Calcification. This is closely tied with the day/night cycle and molecular mechanism behind this synchronization is mysterious till date.
AURELIE MOYA: THE MIND BEHIND RESEARCH
Aurelie Moya and colleagues during their research have succeeded in finding the mystery behind this synchronization of Dinoflagellates. They have characterized the first coral gene that responds to the light cycle They named this gene as STPCA.
This gene makes an enzyme that converts Carbon Dioxide to Bicarbonate (baking soda) and is twice as active at night compared to daytime.
WHAT THEY HAVE FOUND?
The researchers have found that this enzyme concentrates in the watery layer right under the calcified skeleton. Moya and colleagues determined that STPCA becomes more active at night to cope with acid buildup.
The calcification process requires many hydrogen atoms, which during the day can be removed by photosynthesis. But at night, however, hydrogen accumulates which increases the acidity of the coral and to cope up with this increased acidity STPCA creates extra bicarbonate as a buffer to prevent acid damage.
