410 likes | 429 Views
Explore the diverse feeding mechanisms in corals, focusing on heterotrophic nutrition and methods like predation, detritus feeding, and absorption. Learn about polyp anatomy, nematocyst discharge, and feeding responses in Fungia corals. Discover the importance of autotrophic nutrition through photosynthesis and zooxanthellae symbiosis in coral health.
E N D
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.
Chemical Recycling Between Zooxanthellae and Their Coral Hosts