The Electromagnetic Radiation Spectrum Only green and blue

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