Coral Nutrition Coral polyp eating marine worm
Heterotrophic Nutrition • General feeding modes: • predaceous carnivores capturing live prey • detritus feeding • absorption of dissolved organic matter from surrounding water
Heterotrophic Nutrition • Heterotrophic Feeding Methods: • Tentacles capturing prey • Suspension feeding and trap particles with mucus • Feed by mesentery filaments The majority of hermatypic and ahermatypic corals feed on plankton or DOM
Heterotrophic Nutrition • Active predation: • Tentacles capture prey • Found mostly on those that rely on heterotrophic food sources • Hermatypic corals have smaller tentacles and small polyps • Tentacles usually extend at night and retract during the day
Nematocyst • True nematocysts • Spirocysts • Ptychocytes
Nematocyst Discharge http://www.youtube.com/watch?v=-Tp38DUjUnM
Stimulus for Nematocyst Discharge • Mechanical stimulus. • Chemical stimulus (e.g., amino acids) lowers the threshold for mechanical stimulus.
Feeding Response in Fungia http://reefkeeping.com/issues/2007-05/atj/index.php
Fungiascutaria CiliaryMucoid Feeding
Coral Slime- Mucoid Feeding • zooxanthellae produce lots of carbs • excess is trapped in mucus produced by coral and expelled (DOM) • DOM feed on by other orgs • May be a food source for symbionts or to clean sediment off coral
Sediment Clearing http://www.youtube.com/watch?v=19ytYeqvTBc
Photosynthesis 6H2O + 6CO2 + light C6H12O6 + 6O2
Aerobic Respiration C6H12O6 + 6O2 6H2O + 6CO2 + energy
Transmission of Zooxanthellae into Host Tissues • Maternal (direct) transmission. • Environmental (indirect) transmission.
Hermatypic Coral J. P. Hoover, 1998
Benefits to the Coral Host • Higher rates of calcification (skeleton deposition). • Energy and materials for growth, repair, and reproduction. • Removal of chemical wastes from animal metabolism (nutrient recycling). • Receive chemicals that absorb damaging ultraviolet light.
Benefits to the Algal Symbiont • Chemical wastes from animal metabolism are important inorganic nutrients for plants (nutrient recycling). • Surrounding animal tissues can concentration substantial amounts of ultraviolet light absorbing compounds. • Zooxanthellae, nonmotile single cells, get a place to live in the crowded reef environment.