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1. Distribution of light in the ocean. Sunlight zone. Biozone. E uphotic. Epipelagic. D isphotic. Mesopelagic. Bathypelagic. A photic. Abyssopelagic. Fig 13.9. Hatchet fish. 2. Adaptations to the deep sea Bioluminescence Mating Feeding. Gulper eel. Female angler fish. Fig 15-14.
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1. Distribution of light in the ocean Sunlight zone Biozone Euphotic Epipelagic Disphotic Mesopelagic Bathypelagic Aphotic Abyssopelagic Fig 13.9
Hatchet fish • 2. Adaptations to the deep sea • Bioluminescence • Mating • Feeding Gulper eel Female angler fish Fig 15-14
A. Bioluminescence a) What? Definition: The emission of ecologically functional light by living organisms Light is produced by a chemical reaction within the organism – no ‘input’ of energy Note: phosphorescence – emission of light with input of energy fluorescence – input of energy to excite a molecule giving off light • b) Where? • Marine bacteria • Dinoflagellates • All major phyla
“optimizer” Photon of light enzyme substrate • Core of the reaction • has strong antioxidative properties • detoxifies tissues by taking up oxygen free radicals • usually brought into the system by diet or synthesis internally c) How bioluminescence works d) Likely originated to detoxify oxygen derivatives
Bioluminescence in different organisms http://www.lifesci.ucsb.edu/~biolum/chem/detail1.html
e) Examples of bioluminescent organisms & their molecules: • Coelenterazine: most ‘popular’ of the luciferins (substrate); known in cnidarians, molluscs, chaetognaths, fish. • Can act alone or with another enzyme • Often acts together with aequorin • Chemistry: Imidazolopyrazinone • Found in all tissues of the animal • Highest concentration in digestive gland, liver hepatopancreas, organs with high levels of oxidative reactions
Apoaequorin Ca 2+ O2 photon Apoaequorin (enzyme) Aequorin- Coelenterazine (excitable intermediate) Coelenterazine (substrate) • Bacterial luciferin: most often harnessed by other animals and used for light emission (e.g. fish, squid) • Vibrio: a marine bacterium (free-living) that is an endosymbiont in squid • Luminescence is dependent on cell density Colenteramide And CO2 (reduced riboflavin phosphate FMNH2 ) • Aequorin: a ‘luciferase’ (enzyme) that requires calcium • Aequorin is called a ‘photoprotein’ because it requires calcium to work with a luciferin (such as coelenterazine)
f) When is bioluminescence used? (1) lure Angler Fish
(2) Burglar Alarm: startling predators of your predator Cephalopod predation is facilitated by dinoflagellate luminescence ‘Seizure’ Pre-attack ‘Positioning’ Ghost shrimp squid (Fleisher and Case: Biol. Bull. 1995 189:263-271)
(3) Alarm/warning of other colonies: e.g. Pyrosomes Stops feeding and swimming current http://divefilm.com/dive_films/indexC.html
Bacterial endosymbiont in the squid Euprymna scolopes • E. scolopes burries in the sand during the day and forages at night. • More examples: • Krill – use bioluminescence for attracting mates • Uses the bioluminescence produced by the Vibrio to counter-shade it against the moonlight so that prey won’t see its shadow. • Hatchling squid pick up the bacteria and develop a special pouch for them
B. Adaptations - Mating Parasitic male
C. Adaptations - feeding Chauliodus sloani Large teeth Hinged jaw Chiasmodon niger Vast stomach! Fig 15-15
Chauliodus sloani Gulper eel
Carnivorous tunicate Atrial siphon Oral siphon (mouth)
Carnivorous sponge: Asbestopluma From Barkley Sound
Amphipod crustacean
Asbesopluma hypogea – Carnivorous sponge from the Mediterranean (Marseille, France)