Algae Life style Symbiosis
Less well known are the algal relationships with animals. Reef-building corals are basically social Cnidarian polyps. Corals are dependent on light, because the algae are important partners, and they require light. Corals have evolved structures, often tree-like, which offer the algae maximum access to light. The corals' waste-products provide nutrients for the algae so, as with lichen, both partners gain from the association. The algae are golden-brown flagellate algae, often of the genus 'Symbiodinium'. A curious feature of the partnership is that the coral may eject the algae in hard times, and regain them later.