Coral reef basics - symbiosis

Symbiotic relationships
Symbiosis is a long term relationship between two organisms. There are three types of symbiotic relationship: mutualism (where both organisms benefit), commensalism (where one species benefits, but there is no benefit or harm to the other species), and parasitism (where one organism benefits tot he detriment of the other). There are many examples of symbiosis on coral reefs. 

Corals and zoozanthallae
The relationship between the corals and the zoozanthallae is beneficial to both. Corals provide the zoozanthallae with an environment suitable for survival. It is moist and the coral's waste gives energy to the zoozanthallae. Through the process of photosynthesis the zoozanthallae produce compounds that the coral use for food.

Clownfish and Sea Anemones
The Sea Anemones have tentacles with stinging cells. These stinging cells kill many organisms and it is in this way the anemones get their food. Clownfish hide in amongst the tentacles of the Sea Anemone, but are not harmed by them. In this way the clownfish are protected from other predators. Occasionally the Clownfish will catch food for the Sea Anemone.

Sharks and Remoras
Sharks sometimes get parasites which live on the external surface of the shark. Remoras are cleaner fish, and they attach themselves to the shark and kill the parasites. When the shark feeds the Remora are able to eat the scraps from the feed.

Watch the videos below, and take notes about the following symbiotic relationships:
- Christmas tree worms and porites corals
- Coral shrimps and corals
- Goby shrimp and Hawaiian Shrimp Goby
- Cleaner Wrasse and cleaning stations