The Electromagnetic Radiation Spectrum Only green and blue wavelengths pass through water a great distance.
Light Penetration in the Ocean
What color/wavelength of light will animals use?
Types of light production: 1.incandescence – light bulb 2.luminescence- fluorescence bulb What is the difference between these types of light? Bioluminescence: a chemical reaction
What organisms that you know of have bioluminescence? Bioluminescence evolved in several kingdoms. Evolution: In early evolution, O 2 was toxic. Some organisms were able to convert it to a nontoxic substance, which had the tendency to produce photons of light. This may have had a selective advantage to some organisms. Not found in freshwater organisms.
luciferase Luciferin + O 2 oxyluciferin + light
Bacterial Intrinsic Photobacterium
(bacterial) Light emitting organ
Cephalopod Photophore
Examples of Bacterial Photophores: fish, few squid, Pyrosoma (tunicate) How do they get bacteria? organ open to exterior (provide entrance for bacteria to enter) potentially continuous luminescence Pyrosoma
Bacterial photophores- 3 genera Photobacterium (symbiotic relationship) Achromabacteria (2 types of squid use bacteria, the rest (17) have make their own luminescence) Beneckea (not associated with symbiotic relationship) Squid Euprymna- squid hatches w/out bacteria; w/in hours it is infected w/natural populations of bacteria
Tunicate- Pyrosoma- bacterial symbiont (intracellular) Examples of fish that have bacterial photophores: Anglerfish (ceratioids) Pinecone fish (Monocentrids) Lantern eyes/flashlightfish (Anomalopids) Ponyfishes/slipmouths (Leiognathids) Ichthyococcus
Intrinsic photophores: 1.Widely distributed, ex. Cookie cutter shark 2.Numerous photophores 1000’s 3.Make own luminescence 4.Control output of light (on and off)
Control of Bioluminescence: They can control biolum intensity by controlling blood supply to light organ (i.e., control the amt of O 2 -- O 2 decreases light intensity decreases) Light control using a shield Lid Vascular control Rotation of organ
Reproductive advantage Countershading Escape and avoid predation Species recognition Feeding In evolution
Some mesopelagic copepod species are red/black in color. Why?
Malacosteus, possess a cheek photophore that emits a red light, which allows it to detect red animals.
squids- looking for mates.
Some predators can lure prey by mimicking signals of prey. Other predators dangle a lure to attract prey.
mid-water squid releases a bioluminescent cloud to startle and confuse predators. Photoblepharon- blink and run method.
Ctenophore
pterapods
Firefly squid Deep sea squid
Photophores on ventral surface Deep sea gulper
Deep sea viper fish
angler fish