The Electromagnetic Radiation Spectrum

Only green and blue wavelengths pass through water a great distance.

Light Penetration

in the Ocean

Light Penetration

in the Ocean

What color/wavelength of light will animals use?

Types of light production: 1. incandescence – light bulb2. 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, O2 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 + O2 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 shark2. Numerous photophores 1000’s3. Make own luminescence4. 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 O2 -- O2 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