bio

Coral holobiont

The idea that a "coral" is not one organism but a living collective: the cnidarian animal host, the photosynthetic algae inside its cells (zooxanthellae), and an entire associated community of bacteria, fungi and viruses. The whole assembly runs as a single biological unit — trading carbon, nitrogen and signals — and it is this partnership that gives the coral enough energy to secrete the limestone skeleton that builds a reef. Break one link in the holobiont, such as expelling the algae when the water warms, and the whole reef-building machine stalls.