Bioluminescence BY : ASFIYA KHAN

Ocean Zones

The Electromagnetic Radiation Spectrum Light penetration in the ocean The Electromagnetic Radiation Spectrum Only green and blue wavelengths pass through water a great distance.

Light Penetration in the Ocean

Ocean Zones What color/wavelength of light will animals use?

Light Types of light production: incandescence – light bulb 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.

Bioluminescence Chemical Reaction luciferase Luciferin + O2 oxyluciferin + light

Types of Bioluminescence Bacterial Intrinsic Photobacterium

Photophore (bacterial) Light emitting organ

Cephalopod Photophore Cephalopods possess a great variety of light-producing organs (photophores). Some are very small and complex like the drawing below of a section through a photophore of Abralia trigonura which is less than 0.2 mm in diameter and as complex as the eyes of some animals. Some other photophores are very large such the arm tip organs of Taningia which can be nearly 5 cm in length and 2-3 cm wide. Cephalopod photophores have a wide range in structure from a simple group of photogenic cells to organs with photogenic cells surrounded by reflectors, lenses, light guides, color filters and muscles. The latter complex photophores are often able to actively adjust the color, intensity and angular distribution of the light they produce. Photophores of most oceanic cephalopods have intrinsic luminescence with the light coming from their own specialized cells, the photocytes. Photophores of most neritic cephalopods, in contrast, have extrinsic luminescence with the light produced by bacteria that are cultured in specialized light organs of the host cephalopod. Chromatophores - Pigment cells that absorb light leaving the photophore in undesirable directions or that shield the reflectors of the photophore, when the photophore is not active, from reflecting external light that could reveal the presence of the cephalopod. Color filters - Structures within a photophore that restrict the color of the light emitted by the photocytes. Filters can either rely on selective absorption of light (pigment filters) or selective transmission/reflection of light (iridophores). Lenses - A variety of structures that apparently affect the directionality of light are called "lenses." Some of these appear to act like typical optical lenses but the mode of action of others (like those in the illustration to the right) are uncertain. Light guides - Structures that control the direction of emitted light through the use of "light pipes" that rely on total internal reflection. These function in the same manner as fiber-obtic light guides. Photocytes - Cells that produce light (i.e., the bioluminescence). Photogenic crystalloids - Some photocytes have crystalline-like inclusions that are thought to be the actual site within the cell where light is produced. Reflectors - The primary reflectors are structures at the back of a photophore that reflect light toward the exterior. These may be broad-band reflectors that reflect all light or narrow-band reflectors that selectively reflect specific colors. Light not reflected by the latter structure passes through it and is absorbed by chromatophores that usually surround the reflector. Secondary reflectors can be found in various regions near the distal parts of the photophore. These generally have a role in controlling the directionality of the emitted light.

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: Widely distributed, ex. Cookie cutter shark Numerous photophores 1000’s Make own luminescence 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

What are the advantages of using bioluminescence?

Function of Bioluminescence Reproductive advantage Countershading Escape and avoid predation Species recognition Feeding In evolution

Countershading

Camouflage The hatchetfish gets its name from the distinct hatchet-like shape of its body. Hatchetfishes live in the deep ocean at depths down to 4500 feet. They are a small fish growing up to only 4 inches in length. They have upward pointing eyes that enable them to search for food falling from the depths above. These fish have light-producing photophores that run along the length of their body. It is believed they use these light organs to signal others of their own kind during mating. Since these photophores point downward, they may also serve to attract prey from below. Hatchetfishes are found in deep waters all over the world. They feed mainly on copepods and the fry of other fishes. Bioluminescence- Countershading, i.e., match downwelling light

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.

Communication squids- looking for mates.

Predation Some predators can lure prey by mimicking signals of prey. Other predators dangle a lure to attract prey.

Burglar Alarm Theory

Defense mid-water squid releases a bioluminescent cloud to startle and confuse predators. Photoblepharon- blink and run method.

Other bioluminescent animals Ctenophore

pterapods

Firefly squid Deep sea squid The firefly squid is a small member of the squid family, growing to a length of only three inches. The tips of their tentacles are equipped with light-producing organs called photophores. The squid uses these lights to attract it prey. By flashing these lights on and off, they can attract small fish and then pounce on the with their powerful tentacles. The firefly squid is also capable of emitting light from its entire body. The squid's body is covered with tiny photophores that can be flashed in unison or alternated in an endless number of hypnotizing patterns. The firefly squid spends its days at depths of about 1200 feet. At night, it comes up  to the surface to search for food. During spawning season, they can even come close to shore. They can be seen gathering every year from March to May in Toyama Bay in Japan. Toyama Bay is a V-shaped canyon in which the sea floor drops away very suddenly. The flow of the current usually wells up from the bottom so that the squid are pushed up to the top by the water. The area where the squid gather has been designated as special natural treasure. The average life span of a firefly squid is about one year. They are found throughout the western Pacific ocean. Deep sea squid

Deep sea gulper Photophores on ventral surface Size: 6 feet long                                                                                          Size: 6 feet long Location: found world wide Depth 3000-6000 ft The gulper eel has a hinged skull, which can rotate upward to swallow large prey. The gulper eel is particularly well-known for its impossibly large mouth - big enough to get its mouth around (and swallow!) creatures much bigger than itself. The eel's mouth is loosely-hinged, and can be opened wide enough to swallow an animal much larger than itself. The hapless fish is then deposited into a pouch-like lower jaw, which resembles that of a pelican. In fact, it is sometimes referred to as the pelican eel. The gulper's stomach can also stretch to accommodate its large meals. This giant mouth gives the eel its other common name of umbrellamouth gulper. The eel also has a very long, whip-like tail. Specimens that have been brought to the surface in fishing nets have been known to have their long tails tied into several knots. Photophores on ventral surface Deep sea gulper

Deep sea viper fish Location Mesopelagic - most waters of the world Depth: found at up to 5000 ft; day- 5000ft, night 2000 ft Size: 12-24 inches These fangs are so large in fact that they do not fit inside its mouth. Instead, they curve back very close to the fish's eyes. The viper is thought to use these sharp teeth to impale its victims by swimming at them at high speeds. The first vertebra, right behind the head, actually acts as a shock absorber. This fearsome looking creature has a long dorsal spine that is tipped with a photophore, a light-producing organ. The viperfish uses this light organ to attract its prey. By flashing it on and off, it can be used like a fishing lure to attract smaller fish. They have been known to hang motionless in the water, waving their lures over their heads to attract their meals. Vipers have a hinged skull which can be rotated up for swallowing large prey. They also have large stomachs that allow them to stock up on food when ever it is plentiful. The viperfish also has photophores all along the sides of its body. These light organs may be used to signal and attract other viperfishes during mating. Like many deep sea creatures, the viperfish is known to migrate vertically throughout the day.

angler fish

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