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Dive into the depths of the ocean where sunlight is scarce and discover the unique communities of organisms that inhabit the Mesopelagic and Deep Sea zones.
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Honors Marine BiologyModule 14 The Deep Ocean March 28, 2013
Class Challenge Act out something from your favorite Movie or TV script.
Tonight March 28, 2013 WUSF at 8:00pm PBS The Florida Wildlife Corridor
Question 1 • Increased resistance • Buoyancy: Fats and Oils • Air bladders • Water Spider – feathered feet that do not break the surface tension of the water.
Question 2 • Zooplankton, copepodes: Eyes can detect movement, shapes, shadows. • Large organisms, fish and mammals: Very good eye-sight • Fishes: Lateral lines • Dolphins: Echolocation
Question 3 • Transparent (Jelly fish) • Countershading (dorsal dark, ventral silvery white) • Epipelagic organisms are generally silver and blue in color to help them blend in. • Vertically banded to break up silhouette.
Question 4 Inner muscle Structure: large network of veins and arteries; large amount of protein called mygoblin, More Oxygen; darker in color. Outer muscle structure: Used for short, powerful bursts of speed, less myoglobin; lighter in color.
Question 5 Epi means : Top; The Photic is the upper most layer of the pelagic division. The water column that extend from the surface down to about 200 meters.
Question 6 The Neritic is the epipelagic water lying over the continental shelf.
Question 7 Oceanic is the epipelagic water lying over all the rest of the ocean.
Question 8 All the food that supports the epipelagic zone is self-produced.
Matching • D • C • B • A
The Deep Ocean We have been discussing the surface layer of the ocean, the Epipelagic Zone. Now we are going to dive into the deep ocean where light is not so abundant. This area can be divided into two major regions: Mesopelagic zone and the Deep Sea
Mesopelagic zone Is located directly below the epipelagic and receives some sunlight, but not enough to support photosynthesis. (200m – 1000m) This means that there is no primary production. There are some exceptions that we will discuss later.
The Deep Sea Refers to areas where there is no sunlight at all. This area is further divided into zones, each of which contains a distinctly different community of creatures. • Bathypelagic, (1000m – 4000m) • Abyssopelagic (4000m- 6000m) • Hadalpelagic (below 6000m)
Deep Ocean Organisms Require oxygen as well as food and ultimately that oxygen comes from the surface of the ocean. The oxygen reaches the deep by the gradual circulation that takes place in the ocean.
Circulation Begins where surface water becomes very cold, think North Atlantic and Antarctica. Cold water can hold much more dissolved oxygen than warmer water. This very dense, oxygenated water sinks via the process of overturn.
As the oxygen-rich water sinks, it flows throughout the ocean basins of the world, like a conveyor belt, carrying very high concentrations of oxygen to the deep ocean areas.
The water eventually warms and rises to the surface again, producing a worldwide cycle of ocean mixing. Regular mixing cycles provide a good supply of oxygen to support deep ocean organisms. It is believed that the relatively small populations of deep ocean species are not able to utilize the large quantities of oxygen that are available to them.
The Mesopelagic The pelagic layer of the ocean where light can penetrate, yet without the intensity to support photosynthesis. This zone contains the temperature division called the thermocline. The thermocline is a specific depth in the ocean where the water temperature drastically drops as depth increases. The main source for heat in the ocean is solar energy, and as solar energy is lessened, temperatures decrease.
Thermocline Areas above the thermocline contain warm surface water, and areas below it contain cold deep water. So mesopelagic organisms that move throughout the mesopelagic zone experience rapid temperature changes. This is because the creatures move, not because the water changes. Mesopelagic temperatures stay relatively constant throughout the year.
Photophores Since there is not enough sunlight, phytoplankton cannot live in the mesopelagic; however zooplankton are plentiful. Krill and copepods are common, as well as shrimp. These crustaceans differ from the epipelagic counterparts in that they have unique structures to produce light called photophores.
Photophores Are typically arranged in distinct patterns unique to each species. Most groups of animals living in the mesopelagic are the same as those in the epipelagic, but here are some interesting crustaceans called ostracods. See page 334-5
The living Planet:The Open Ocean • http://youtu.be/d7WtduFycDY • Creatures of the Deep Ocean HD | National Geographic Documentary • http://youtu.be/VQZ3niWcyCE
Mesopelagic Food Web Because food is relatively scarce, it is beneficial for mesopelagic creatures to have mechanisms to capture as much prey as possible. Many shrimp and squid conserve energy by sitting and waiting for food to come by. When that happens they then capture their prey using multiple arms. This sit and wait strategy is beneficial in that it does not require much energy.
Very little muscle is needed because creatures do not have to chase down prey. Their flesh is watery and without much muscle tone. They have no need for a swim bladder because they have soft, weak, light-weight bones and reduces muscle mass to keep them from sinking.
Many animals are neutrally buoyant, which means that at rest, they will neither float or sink. Most fishes in this zone are not picky and feed on anything they can collect and fit into their mouths. They have large mouths with long teeth for grasping and hinged jaws that can open wide enough to accommodate large prey.
Some prey can eat prey larger than themselves. The viper fish have large stomachs that allow for them to digest large prey. It also allows them to feed voraciously when food is plentiful.
Some mesopelagic organisms migrate to the food-filled epipelagic as night. This is called vertical migration, any many organisms do this. They make their migration at night to avoid being spotted by predators during the day.
Fish that vertically migrate: Have different physical features: • They have large muscles and strong bones. • They have swim bladders • They can tolerate drastic changes in both temperature and pressure as they move up and down the water column. • As Migrators obtain their food from outside the mesopelagic zone, the resulting energy can then be taken advantage of by other mesopelagic predators who feed on the Migrators.
WW II Sonar See page 337 - 8
Mesopelagic Body Design Because these organisms live in an environment devoid of light fish have: • Large, sensitive eyes • Tubular eyes • Sensitive lateral lines sensing vibrations in the water. Their bodies are quite long, therefore the lateral lines increase in sensitivity to their surroundings.
Camouflage to keep from being detected • Countershading (silver, black or red) • Transparency (usually living in the upper mesopelagic ) • Bioluminescence: The production of visible light by living organisms, usually located on the undersides of their bodies. Also known as Counterillumination
Why would an animal be RED See page 339
Bioluminenscence is used as: • Camouflage • Aid in identification of like species • Communication • Mating • Defense mechanism (squid and octopuses produce bioluminescent ink; and some fish produce red light and most fish cannot detect red light)
Creatures of the Deep Ocean HD | National Geographic Documentary http://youtu.be/VQZ3niWcyCE
Homework • Take Module 13 Test • Read Module 14 pages 333 – 351 • Answer On Your Own questions 14.1 – 14.11 • Answer Study Guide questions 1 – 28 • Oral presentation for your Deep Ocean creature • Notebook check on April 4 Through Module 13.
