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Ocean Layers. Layers / Zones of the Ocean. Sunlit zone. Twilight Zone. Midnight Zone. Light Zones. PHOTIC/SUNLIGHT ZONE – 200 m Plants thrive; food relatively abundant. DYSPHOTIC/TWILIGHT ZONE – 1000 m
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Sunlit zone Twilight Zone Midnight Zone Light Zones PHOTIC/SUNLIGHT ZONE – 200 m Plants thrive; food relatively abundant DYSPHOTIC/TWILIGHT ZONE – 1000 m Dim light can’t support plants, reduced food; 20% of photic zone production; T= 23 >> 4 degrees C (thermocline) APHOTIC/MIDNIGHT ZONE – below 1000m Perpetual darkness; only 5% of photic zone food production; T= 4 degrees C
1.Epipelagic Zone “The Sunlight Zone” • The surface layer of the ocean. It extends from the surface to 200 meters (656 feet). • It is also known as the sunlight zone because this is where most of the visible light exists. Therefore this is the only zone that supports plant life due to the need for the sun for photosynthesis. • With the light comes heat. This heat is responsible for the wide range of temperatures that occur in this zone • Ideal for 90% of all ocean creatures, such as: • Turtles, Fish, Sharks, Sting Rays, Jellyfish, and a variety of plant life
2. Mesopelagic Zone“The Twilight Zone” • Extending from 200 meters (656 feet) to 1000 meters (3281 feet). • the twilight zone or the midwater zone. The light that penetrates to this depth is extremely faint. • It is in this zone that we begin to see the twinkling lights of bioluminescent creatures. A great diversity of strange and bizarre fishes can be found here. • Creatures: swordfish, cuttlefish, squid, eels
Characteristics of Twilight Zone Fishes • Photophores on ventral surfaces (countershading) • Small in size (food scarce) • Large mouths relative to body size • Unhingeable jaws to swallow large prey • Large teeth • Many are black or red (invisible) • Large eyes (capture available light) • Vertical migrators (up to photic zone at night) - Black or silver - Well-developed swim bladders/muscles/bones • Non-migrators (remain in twilight zone) - No swim bladder/weak bones/flabby muscles
Characteristics of Twilight Zone Fishes • Photophores on ventral surfaces (countershading) • Small in size (food scarce) • Large mouths relative to body size • Unhingeable jaws to swallow large prey • Large teeth • Many are black or red (invisible) • Large eyes (capture available light) • Vertical migrators (up to photic zone at night) - Black or silver - Well-developed swim bladders/muscles/bones • Non-migrators (remain in twilight zone) - No swim bladder/weak bones/flabby muscles
Shining Tubeshoulder This shiny, black fish has photophores on its belly and a strange tube on each shoulder. These tubes can release a glowing slime. The slime’s glow may distract predatory fishes while the tubeshoulder escapes into the darkness. Grows to 13 inches long.
Bathypelagic Zone“The Midnight Zone” • the midnight zone or the dark zone • This zone extends from 1000 meters (3281 feet) down to 4000 meters (13,124 feet). Here the only visible light is that produced by the creatures themselves. The water pressure at this depth is immense, reaching 5,850 pounds per square inch. In spite of the pressure, a surprisingly large number of creatures can be found here. • Sperm whales can dive down to this level in search of food. Most of the animals that live at these depths are black or red in color due to the lack of light. • Creatures: fish, mollusks, crustaceans, Fangtooth
Characteristics of Midnight Zone Fishes • Single largest habitat on earth! • No countershading bioluminescence • Fewer photophores: on heads and sides • Eyes often absent or reduced • Fish sluggish or usually immobile • Flabby muscles, weak skeletons • Almost all lack swim bladder • Huge mouths • Small size • Black in color
Abyssopelagic Zone“The Abyss” • It extends from 4000 meters (13,124 feet) to 6000 meters (19,686 feet). The name comes from a Greek word meaning "no bottom". • The water temperature is near freezing, and there is no light at all. Very few creatures can be found at these crushing depths. • Most of these are invertebrates such as basket stars and tiny squids. Also,anglerfish and some unidentified species • Three-quarters of the ocean floor lies within this zone. The deepest fish ever discovered was found in the Puerto Rico Trench at a depth of 27,460 feet (8,372 meters).
Hadalpelagic Zone“The Trenches” • This layer extends from 6000 meters (19,686 feet) to the bottom of the deepest parts of the ocean. These areas are mostly found in deep water trenches and canyons. The deepest point in the ocean is located in the Mariana Trench off the coast of Japan at 35,797 feet (10,911 meters). • The temperature of the water is just above freezing, and the pressure is an incredible eight tons per square inch. In spite of the pressure and temperature, life can still be found here. • Invertebrates such as starfish and tube worms can thrive at these depths. Also, sea cucumbers and viper fish
Hydrothermal Vents • First discovery in 1977 -Spreading ridge east of Galapagos Islands; divergent plates • Water: - Up to 400 degrees C (doesn’t boil, too much pressure) - Highly acidic - Large amounts of hydrogen sulfide (toxic to most animals); sulfides of iron, zinc, copper, and other metals precipitate and disburse as “black smoke” = black smokers • May be more than a mile deep - No light - No photosynthesis; chemosynthetically based food web
Hydrothermal Vents • First discovery in 1977 -Spreading ridge east of Galapagos Islands; divergent plates • Water: - Up to 400 degrees C (doesn’t boil, too much pressure) - Highly acidic - Large amounts of hydrogen sulfide (toxic to most animals); sulfides of iron, zinc, copper, and other metals precipitate and disburse as “black smoke” = black smokers • May be more than a mile deep - No light - No photosynthesis; chemosynthetically based food web
Chemosynthesis: The use of energy released by inorganic chemical reactions to produce food (hydrogen sulfide, methane, etc.) Bacteria oxidize hydrogen sulfide to sulfur 6CO2 + 24H2S + 6O2 = C6H12O6 + 24S + 18H2O Photosynthesis: The use of solar energy to make organic matter. 6CO2 + 12H2O = C6H12O6 + 6H2O + 6O2
Giant clams Galapagos Rift 2002 Dr. Tim Shank
Inside a Tubewormfrom NOVA Web site Tubeworms are animals yet they have no mouth, no stomach, no intestine, and no way to eliminate waste.