Brandt (1883) Brown “inclusions” are plant-like organisms that live within the cells Brown “inclusions” are plant-like organisms that live within.

Brandt (1883)Brandt (1883)

Brown “inclusions” are plant-like organisms that Brown “inclusions” are plant-like organisms that live within the cells live within the cells

of the coral!of the coral!

The life cycleThe life cycleof the zooxanthellaof the zooxanthella(Freudenthal 1962). (Freudenthal 1962).

Host “wastes”Host “wastes”

PhotosyntheticPhotosyntheticproductsproducts

Corals and zooxanthellae: mutualist symbiosesCorals and zooxanthellae: mutualist symbioses

Coral cell

SunlightSunlight

Low external resourcesLow external resources(ie NH(ie NH33 and PO and PO44

2-2-))

HostHost ZooxanthellaeZooxanthellae

Amino acidsAmino acids

NHNH44++

Productivity of open ocean~ 0.01 g C m-2 d-1

Productivity within coral reefsAlgal turfs: 280 g C m-2 d-1 Corals: 40 g C m-2 d-1 Benthic microalgae: 363 g C m-2 d-1

(reviewed by Hatcher 1988).

Productivity of open ocean~ 0.01 g C m-2 d-1

Productivity within coral reefsAlgal turfs: 280 g C m-2 d-1 Corals: 40 g C m-2 d-1 Benthic microalgae: 363 g C m-2 d-1

(reviewed by Hatcher 1988).