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Marine Conservation Science and Policy Service learning Program

Scientists have divided the ocean into five main layers. These layers, known as "zones", extend from the surface to the most extreme depths where light can no longer penetrate. These deep zones are where some of the most bizarre and fascinating creatures in the sea can be found. As we dive deeper into these largely unexplored places, the temperature drops and the pressure increases at an astounding rate. The following diagram lists each of these zones in order of depth.

Module 1: Ocean and Coastal Habitats

Sunshine State Standards SC.912.E.7.2, SC.912.E.7.4, SC.912.E.7.5, SC.912.E.7.8, SC.912.E.7.9, SC.912.E.6.3, SC.912.E.6.5

Objectives

Students will understand the Ocean Zones through different experiments.

Identify various coastal and ocean habitats

Describe the different ocean zones

Examine the adaptations of aquatic species that allow them to live in certain habitats

Students will experiment with a model of what happens to light and colors as one descends into the ocean.

Students will describe at least two adaptations to low or no ambient light on the part of deep-sea organisms

Students work in small groups to experiment with currents caused by temperature variations that simulate the origins and flow of polar bottom currents.

Section 1: Ocean Zones

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Vocabulary

Abyssopelagic Zone- The next layer is called the abyssopelagic zone, also known as the abyssal zone or simply as 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. 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).

Bathypelagic Zone- The next layer is called the bathypelagic zone. It is sometimes referred to as 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.

Benthic- Pertaining to the ocean floor.

Consumer- An organism that consumes other organisms as a food source.

Continental margin- Underwater plains connected to continents, separating them from the deep ocean floor.

Chemosynthesis- The chemical process by which bacteria, by oxidizing hydrogen sulfide, serve as primary producer for a marine community.

Cosmic rain- In mid-1997, however, scientists offered a new theory on the how the oceans possibly filled in. The National Aeronautics and Space Administration's Polar satellite, launched in early 1996, discovered that small comets about 40 feet (12 meters) in diameter are bombarding Earth's atmosphere at a rate of about 43,000 a day. These comets break up into icy fragments at heights 600 to 15,000 miles (960 to 24,000 kilometers) above ground. Sunlight then vaporizes these fragments into huge clouds, which condense into rain as they sink lower in the atmosphere.

Epipelagic Zone- The surface layer of the ocean is known as the epipelagic zone and 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. With the light come heat. This heat is responsible for the wide range of temperatures that occur in this zone.

Fracture zone- Faults in the ocean floor that form at nearly right angles to the ocean's major ridges.

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Guyot- An extinct, submarine volcano with a flat top.

Hadalpelagic Zone- Beyond the abyssopelagic zone lies the forbidding hadalpelagic zone. 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. That is approximately the weight of 48 Boeing 747 jets. 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

Mesopelagic Zone- Below the epipelagic zone is the mesopelagic zone, extending from 200 meters (656 feet) to 1000 meters (3281 feet). The mesopelagic zone is sometimes referred to as 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.

Pelagic- The water portion of the ocean.

Photosynthesis- The process by which green plants produce energy by converting carbon dioxide, water, and other nutrients to simple carbohydrates, releasing oxygen as a by-product.

Phytoplankton- Microscopic aquatic plants.

Producer- An organism that is capable of utilizing nonliving materials and an external energy source to produce organic molecules (for example, carbohydrates), which are then used as food.

Ridge- Very long underwater mountain ranges created as a by-product of seafloor spreading.

Rift- Crevice that runs down the middle of a ridge.

Seafloor spreading- Process whereby new oceanic crust is created at ridges.

Seamount- Active or inactive submarine volcano.

Zooplankton- Microscopic aquatic animals.

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Background

An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.

More than half of this area is over 3,000 meters (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt.

Scientists estimate that 230,000 marine life forms of all types are currently known, but the total could be up to 10 times that number.

Though generally described as several 'separate' oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean. This concept of a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.

The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria. These divisions are (in descending order of size):

Pacific Ocean, which separates Asia and Australia from the Americas Atlantic Ocean, which separates the Americas from Eurasia and Africa Indian Ocean, which washes upon southern Asia and separates Africa and

Australia Southern Ocean, which, unlike other oceans, has no landmass separating it from

other oceans and is therefore sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans, which encircles Antarctica and covers much of the Antarctic

Arctic Ocean, sometimes considered a sea of the Atlantic, which covers much of the Arctic and washes upon northern North America and Eurasia

The Pacific and Atlantic may be further subdivided by the equator into northern and southern portions. Smaller regions of the oceans are called seas, gulfs, bays, straits and other names.

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Origin of ocean water

One scientific theory about the origin of ocean water states that as Earth formed from a cloud of gas and dust more than 4.5 billion years ago, a huge amount of lighter elements (including hydrogen and oxygen) became trapped inside the molten interior of the young planet. During the first one to two billion years after Earth's formation, these elemental gases rose through thousands of miles of molten and melting rock to erupt on the surface through volcanoes and fissures (long narrow cracks).

Within the planet and above the surface, oxygen combined with hydrogen to form water. Enormous quantities of water shrouded the globe as an incredibly dense atmosphere of water vapor. Near the top of the atmosphere, where heat could be lost to outer space, water vapor condensed to liquid and fell back into the water vapor layer below, cooling the layer. This atmospheric cooling process continued until the first raindrops fell to the young Earth's surface and flashed into steam. This was the beginning of a fantastic rainstorm that, with the passage of time, gradually filled the ocean basins.

Scientists calculate that this cosmic rain adds one inch of water to Earth's surface every 10,000 to 20,000 years. This amount of water could have been enough to fill the oceans if these comets have been entering Earth's atmosphere since the planet's beginning 4.5 billion years ago.

Ocean and life

The ocean has a significant effect on the biosphere. Oceanic evaporation, as a phase of the water cycle, is the source of most rainfall, and ocean temperatures determine

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climate and wind patterns that affect life on land. Life within the ocean evolved 3 billion years prior to life on land. Both the depth and distance from shore strongly influence the amount and kinds of plants and animals that live there.

Physical properties

The area of the World Ocean is 361×106 km2. Its volume is approximately 1.3 billion cubic kilometers. This can be thought of as a cube of water with an edge length of 1,111 kilometers (690 mi). Its average depth is 3,790 meters (12,430 ft), and its maximum depth is 10,923 meters. Nearly half of the world's marine waters are over 3,000 meters (9,800

ft) deep. The vast expanses of deep ocean (anything below 200 meters (660 ft) cover about 66% of the Earth's surface. This does not include seas not connected to the World Ocean, such as the Caspian Sea.

The total mass of the hydrosphere is about 1,400,000,000,000,000,000 metric tons (1.5×1018 short tons) or 1.4×1021 kg, which is about 0.023 percent of the Earth's total mass. Less than 3 percent is freshwater; the rest is saltwater, mostly in the ocean.

Color

A common misconception is that the oceans are blue primarily because the sky is blue. In fact, water has a very slight blue color that can only be seen in large volumes. While the sky's reflection does contribute to the blue appearance of the surface, it is not the primary cause. The primary cause is the absorption by the water molecules' nuclei of red photons from the incoming light, the only known example of color in nature resulting from vibrational, rather than electronic, dynamics.

Glow

Sailors and other mariners have reported that the ocean often emits a visible glow, or luminescence, which extends for miles at night. In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow. It may be caused by bioluminescence. (Image: The "milk sea" in a composite satellite image, and the region of the

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Indian Ocean off the coast of Somalia where it was spotted by the Defense Meteorological Satellite Program.)

Mariners have long told of rare nighttime events in which the ocean glows intensely as far as the eye can see in all directions.

Fictionally, such a ―milky sea‖ is encountered by the Nautilus in Jules Verne classic ―20,000 Leagues Under the Sea.‖

Scientists don’t have a good handle what’s going on. But satellite sensors have now provided the first pictures of a milky sea and given new hope to learning more about the elusive events.

The newly released images show a vast region of the Indian Ocean, about the size of Connecticut, glowing three nights in a row. The luminescence was also spotted from a ship in the area.

―The circumstances under which milky seas form is almost entirely unknown,‖ says Steven Miller, a Naval Research Laboratory scientist who led the space-based discovery. ―Even the source for the light emission is under debate.‖

Scientists suspect bioluminescent bacteria are behind the phenomenon. Such creatures produce a continuous glow, in contrast to the brief, bright flashes of light produced by ―dinoflagellate‖ bioluminescent organims that are seen more commonly lighting up ship wakes and breaking waves.

―The problem with the bacteria hypothesis is that an extremely high concentration of bacteria must exist before they begin to produce light,‖ Miller told LiveScience. ―But what could possibly support the occurrence of such a large population?‖

One idea, put forward by the lone research vessel to ever encounter a milky sea, is that the bacteria are not free-living, but instead are living off some local supporting ―substrate.‖

The mystery highlights how little scientists know about the ocean. Milky seas appear to be most prevalent in the Indian Ocean, where there are many trade routes, and near Indonesia.

―But there could be other areas we simply don’t know about yet,‖ Miller said. ―In fact, we’re already beginning to receive feedback from additional witnesses of milky seas. Some of these accounts occurred in regions we had not thought to look before, and we’re currently working to find matches with the satellite data.‖

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There have been 235 documented sightings of milky seas since 1915 – mainly concentrated in the north-western Indian Ocean and near Java, Indonesia.

Exploration

Ocean travel by boat dates back to prehistoric times, but only in modern times has extensive underwater travel become possible.

The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean near the Northern Mariana Islands. Its maximum depth has been estimated to be 10,971 meters (35,994 ft) (plus or minus 11 meters; see the Mariana Trench article for discussion of the various estimates of the maximum depth.) The British naval vessel, Challenger II surveyed the trench in 1951 and named the deepest part of the trench, the "Challenger Deep". In 1960, the Trieste successfully reached the bottom of the trench, manned by a crew of two men.

Much of the ocean bottom remains unexplored and unmapped. A global image of many underwater features larger than 10 kilometers (6.2 mi) was created in 1995 based on gravitational distortions of the nearby sea surface.

Culture

The original concept of "ocean" goes back to notions of Mesopotamian and Indo-European mythology, imagining the world to be encircled by a great river. Okeanos in Greek, reflects the ancient Greek observation that a strong current flowed off Gibraltar and their subsequent

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assumption that it was a great river. (Compare also Samudra from Hindu mythology and Jörmungandr from Norse mythology.) The world was imagined to be enclosed by a celestial ocean above the heavens, and an ocean of the underworld below.

Artworks which depict maritime themes are known as marine art, a term which particularly applies to common styles of European painting of the 17th to 19th centuries.

Ocean basin

Ocean basins are that part of Earth's surface that extends seaward from the continental margins (underwater plains connected to continents, separating them from the deep ocean floor). Basins range from an average water depth of about 6,500 feet (2,000 meters) down into the deepest trenches. Ocean basins cover about 70 percent of the total ocean area.

The familiar landscapes of continents are mirrored, and generally magnified, by similar features in the ocean basin. The largest underwater mountains, for example, are higher than those on the continents. Underwater plains are flatter and more extensive than those on the continents. All basins contain certain common features that include oceanic ridges, trenches, fracture zones, abyssal plains, and volcanic cones.

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Oceanic ridges - Enormous mountain ranges, or oceanic ridges, cover the ocean floor. The Mid-Atlantic Ridge, for example, begins at the tip of Greenland, runs down the center of the Atlantic Ocean between the Americas on the west and Africa on the east, and ends at the southern tip of the African continent. At that point, it stretches around the eastern edge of Africa, where it becomes the Mid-Indian Ridge. That ridge continues eastward, making connections with other ridges that eventually end along the western coastline of South and Central America. Some scientists say this is a single oceanic ridge that encircles Earth, one that stretches a total of more than 40,000 miles (65,000 kilometers).

In most locations, oceanic ridges are 6,500 feet (2,000 meters) or more below the surface of the oceans. In a few places, however, they actually

extend above sea level and form islands. Iceland (in the North Atlantic), the Azores (about 900 miles [about 1,500 kilometers] off the coast of Portugal), and Tristan de Cunha (in the South Atlantic midway between southern Africa and South America) are examples of such islands.

Running along the middle of an oceanic ridge, there is often a deep crevice known as a rift, or median valley. This central rift can plunge as far as 6,500 feet (2,000 meters) below the top of the ridge that surrounds it. Scientists believe ocean ridges are formed when molten rock, or magma, escapes from Earth's interior to form the seafloor, a process known as seafloor spreading. Rifts may be the specific parts of the ridges where the magma escapes.

Trenches - Trenches are long, narrow, canyon like structures, most often found next to a continental margin. They occur much more commonly in the Pacific than in any of the other oceans. The deepest trench on Earth is the Mariana Trench, which runs from the coast of Japan south and then west toward the Philippine Islands—a distance of about 1,580 miles (2,540 kilometers).

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Its deepest spot is 36,198 feet (11,033 meters) below sea level. The longest trench is located along the coast of Peru and Chile. Its total length is 3,700 miles (5,950 kilometers) and it has a maximum depth of 26,420 feet (8,050 meters). Earthquakes and volcanic activity are commonly associated with trenches.

Fracture zones - Fracture zones are regions where sections of the ocean floor slide past each other, relieving tension created by seafloor spreading at the ocean ridges. Ocean crust in a fracture zone looks like it has been sliced up by a giant knife. The faults in a zone usually cut across ocean ridges, often nearly at right angles to the ridge. A map of the North Atlantic Ocean basin, for example, shows the Mid-Atlantic Ridge traveling from north to south across the middle of the basin, with dozens of fracture zones cutting across the ridge from east to west.

Abyssal plains - Abyssal plains are relatively flat areas of the ocean basin with slopes of less than one foot of elevation difference for each thousand feet of distance. They tend to be found at depths of 13,000 to 16,000 feet (4,000 to 5,000 meters). Oceanographers believe that abyssal plains are so flat because they are covered with sediments (clay, sand, and gravel) that have been washed off the surface of the continents for hundreds of thousands of years. On the abyssal plains, these layers of sediment have now covered up any irregularities that may exist in the rock of the ocean floor beneath them.

Abyssal plains found in the Atlantic and Indian Oceans tend to be more extensive than those in the Pacific Ocean. One reason for this phenomenon is that the majority of the world's largest rivers empty into either the Atlantic or the Indian Oceans, providing both

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ocean basins with an endless supply of the sediments from which abyssal plains are made.

Volcanic cones - Ocean basins are alive with volcanic activity. Magma flows upward from the mantle to the ocean bottom not only through rifts, but also through numerous volcanoes and other openings in the ocean floor. Seamounts are submarine volcanoes and can be either active or extinct. Guyots are extinct volcanoes that were once above sea level but have since receded below the surface. As they receded, wave or current action eroded the top of the volcano to a flat surface.

Seamounts and guyots typically rise about 0.6 mile (1 kilometer) above the ocean floor. One of the largest known seamounts is Great Meteor Seamount in the northeastern part of the Atlantic Ocean. It extends to a height of more than 1,300 feet (4,000 meters) above the ocean floor.

Ocean Zones

Ocean zones are layers within the oceans that contain distinctive plant and animal life. They are sometimes referred to as ocean layers or environmental zones. The ocean environment is divided into two broad categories, known as realms: the benthic realm (consisting of the seafloor) and the pelagic realm (consisting of the ocean waters). These two realms are then subdivided into separate zones according to the depth of the water.

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Regions and depths

Oceanographers divide the ocean into regions depending on physical and biological conditions of these areas. The pelagic zone includes all open ocean regions, and can be divided into further regions categorized by depth and light abundance. The photic zone covers the oceans from surface level to 200 meters down. This is the region where photosynthesis can occur and therefore is the most biodiverse. Since plants require photosynthesis, life found deeper than this must

either rely on material sinking from above (see marine snow) or find another energy source; hydrothermal vents are the primary option in what is known as the aphotic zone (depths exceeding 200 m). The pelagic part of the photic zone is known as the epipelagic. The pelagic part of the aphotic zone can be further divided into regions that succeed each other vertically according to temperature.

The mesopelagic is the uppermost region. Its lowermost boundary is at a thermocline of 12 °C (54 °F), which, in the tropics generally lies at 700–1,000 meters (2,300–3,300 ft). Next is the bathypelagic lying between 10-4 °C (43 °F), typically between 700–1,000 meters (2,300–3,300 ft) and 2,000–4,000 meters (6,600–13,000 ft) Lying along the top of the abyssal plain is the abyssalpelagic, whose lower boundary lies at about 6,000 meters (20,000 ft). The last zone includes the deep trenches, and is known as the hadalpelagic. This lies between 6,000–11,000 meters (20,000–36,000 ft) and is the deepest oceanic zone.

Along with pelagic aphotic zones there are also benthic aphotic zones. These correspond to the three deepest zones of the deep-sea. The bathyal zone covers the continental slope down to about 4,000 meters (13,000 ft). The abyssal zone covers the abyssal plains between 4,000 and 6,000 m. Lastly, the hadal zone corresponds to the hadalpelagic zone which is found in the oceanic trenches. The pelagic zone can also be split into two subregions, the neritic zone and the oceanic zone. The neritic encompasses the water mass directly above the continental shelves, while the oceanic zone includes all the completely open water. In contrast, the littoral zone covers the region between low and high tide and represents the transitional area between marine and terrestrial conditions. It is also known as the intertidal zone because it is the area where tide level affects the conditions of the region.

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Water depth versus light penetration

Sunlight obviously cannot penetrate beyond a certain depth in the ocean. Some organisms have, however, evolved to cope with the absence of sunlight at great depths. Plants require sunlight to carry on photosynthesis—the process by which they convert carbon dioxide, water, and other nutrients to simple carbohydrates to produce energy, releasing oxygen as a by-product. Below a depth of about 660 feet (200 meters), not enough sunlight penetrates to allow photosynthesis to occur. The area of the ocean where

photosynthesis occurs is known as the euphotic zone (meaning "good light").

From the standpoint of living organisms, the euphotic zone is probably the most important of all oceanic zones. By some estimates, about two-thirds of all

the photosynthetic

activity that occurs on Earth (on land and in the water) takes place within the euphotic zone.

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From 660 to 3,000 feet (200 to 900 meters), only about 1 percent of sunlight penetrates. This layer is known as the dysphotic zone (meaning "bad light"). Below this layer, down to the deepest parts of the ocean, it is perpetual night. This last layer is called the aphotic zone (meaning "without light"). At one time, scientists thought that very little life existed within the aphotic zone. However, they now know that a variety of interesting organisms can be found living on the deepest parts of the ocean floor.

The benthic realm

The benthic realm extends from the shoreline to the deepest parts of the ocean floor. The benthic realm is an especially rich environment for living organisms. Scientists now believe that up to 98 percent of all marine species are found in or near the ocean floor. Some of these are fish or shellfish swimming just above the ocean floor. Most are organisms that burrow in the sand or mud, bore into or are attached to rocks, live in shells, or simply move about on the ocean floor.

In the deeper parts of the ocean floor, below the euphotic zone, no herbivores (plant eaters) can survive. However, the "rain" of dead organic matter from above still

supports thriving bottom communities.

The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached

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to the bottom. The superficial layer of the soil lining the given body of water, the benthic boundary layer, is an integral part of the benthic zone, as it influences greatly the biological activity which takes place there. Examples of contact soil layers include sand bottoms, rock outcrops, coral, and bay mud.

Organisms

Benthos are the organisms which live in the benthic zone, and are different from those elsewhere in the water column. Many are adapted to live on the substrate (bottom). In their habitats they can be considered as dominant creatures. Many organisms adapted to deep-water pressure cannot survive in the upper parts of the water column. The pressure difference can be very significant (approximately one atmosphere for each 10 meters of water depth).

Because light does not penetrate very deep ocean-water, the energy source for the benthic ecosystem is often organic matter from higher up in the water column which drifts down to the depths. This dead and decaying matter sustains the benthic food chain; most organisms in the benthic zone are scavengers or detritivores. Some microorganisms use chemosynthesis to produce biomass.

Benthic organisms can be divided into two categories based on whether they make their home on the ocean floor or an inch or two into the ocean floor. Those living on the surface of the ocean floor are known as epifauna. Those who live burrowed into the ocean floor are known as infauna.

The pelagic realm

In the region of the pelagic zone from the surface to 660 feet (200 meters), phytoplankton (algae and microscopic plants) live. They are the primary producers of the ocean, the lowest level on the oceanic food web. They use the process of photosynthesis to provide food for themselves and for higher organisms.

On the next level upward in the pelagic food web are the primary consumers, the

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zooplankton (microscopic animals). They feed on phytoplankton and, in turn, become food for larger animals (secondary consumers) such as sardines, herring, tuna, bonito, and other kinds of fish and swimming mammals. At the top of this food web are the ultimate consumers, the toothed whales.

In the region from a depth of about 660 to 3,000 feet (200 to 900 meters), a number of organisms survive by spending daylight hours within this region and then rising toward the surface during evening hours. In this way, they can feed off the phytoplankton and zooplankton available near and on the surface of the water while avoiding predators during the day. The most common organisms found in this region are small fish, squid, and simple shellfish. A number of these organisms have evolved some interesting adaptations for living in this twilight world. They often have very large eyes, capable of detecting light only 1 percent as intense as that visible to the human eye. A majority

also have light-producing organs that give off a phosphorescence that makes them glow in the dark.

Organisms found below 3,000 feet (900 meters) have also evolved some bizarre adaptations for survival in their lightless environment. In the deeper regions, pressures may exceed 500 times that of atmospheric pressure, or the equivalent of several tons per square inch. Temperatures never get much warmer than about 37°F (3°C). Organisms within these regions generally prey on each other. They have developed special features such as expandable mouths, large and very sharp teeth, and special strategies for hunting or luring prey.

Any water in the sea that is not close to the bottom or near to the shore is in the pelagic zone. The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes from the surface of the sea almost to the bottom, as shown in the diagram below. Conditions change deeper down the water column; the pressure increases, the temperature drops and there is less light. Depending on the depth, scientists further subdivide the water column, rather like the Earth's atmosphere is divided into different layers.

The pelagic zone occupies 1,370 million cubic kilometers (330 million cubic miles) and has a vertical range up to 11 kilometers (6.8 miles). Fish that live in the pelagic zone are called pelagic fish. Pelagic life decreases with increasing depth. It is affected by light levels, pressure, temperature, salinity, the supply of dissolved oxygen and nutrients, and the submarine topography. In deep water,

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the pelagic zone is sometimes called the open-ocean zone and can be contrasted with water that is near the coast or on the continental shelf. However in other contexts, coastal water that is not near the bottom is still said to be in the pelagic zone.

The pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea. The benthic zone is the ecological region at the very bottom of the sea. It includes the sediment surface and some sub-surface layers. Marine organisms living in this zone, such as clams and crabs, are called benthos. The demersal zone is just above the benthic zone. It can be significantly affected by the seabed and the life that lives there. Fish that live in the demersal zone are called demersal fish. Demersal fish can be divided into benthic fish, which are denser than water so they can rest on the bottom, and benthopelagic fish, which swim in the water column just above the bottom. Demersal fish are also known as bottom feeders and groundfish.

Depth and layers

Epipelagic (sunlit)

The illuminated surface zone where there is enough light for photosynthesis. Due to this, plants and animals are largely concentrated in this zone. Nearly all primary production in the ocean occurs here. This layer is the domain of fish such as tuna, many sharks, dolphin fish, and jellyfish. This zone is also known as the surface zone.

Mesopelagic (twilight)

Although some light penetrates this deep, it is insufficient for photosynthesis. At about 500 m the water becomes depleted of oxygen. Still, an abundance of life copes with more efficient gills or minimal movement. Animals such as swordfish, squids, wolffish, a few species of cuttlefish, and other semi-deep-sea creatures live here. Many bioluminescent organisms live in this zone. Due to the relative lack of nutritious food found in this zone, some creatures living in the mesopelagic zone will rise to the epipelagic zone at night in order to feed.

Bathypelagic (darkzone)

By this depth the ocean is pitch black, apart from the occasional bioluminescent organism, such as lanternfish. There are no living plants, and most animals survive by

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consuming the snow of detritus falling from the zones above or (like the marine hatchetfish) by preying upon others. Giant squid (as well as smaller squids & Dumbo octopodes) live at this depth, and here they are hunted by deep-diving sperm whales.

Abyssopelagic (lower midnight)

Very few creatures are sufficiently adapted to survive in the cold temperatures and incredible pressures found at this depth. Among the species found in this zone are several species of squid; echinoderms including the basket star, swimming cucumber, and the sea pig; and marine arthropods including the sea spider. Many of the species living at these depths have evolved to be transparent and eyeless as a result of the total lack of light in this zone.

Hadopelagic

This zone is mostly unknown, and very few species are known to live here (in the open areas). However, many organisms live in hydrothermal vents in this and other zones. Some define the hadopelagic as waters below 6,000 m (19,685 ft), whether in a trench or not.

The bathypelagic, abyssopelagic, and hadopelagic zones are very similar in character, and some marine biologists combine them into a single zone or consider the latter two to be the same. The abyssal plain is covered with soft sludge covered by the dead organisms from above.

Minerals Nutrients

Nitrogen is generally the limiting mineral nutrient for primary production in the oceans, although iron is also limiting in some oceans. When organisms die, they sink and take their minerals with them to the bottom where the minerals are released by decomposers. Consequently, cold deep ocean water is often much higher in essential mineral nutrients than surface waters where primary production depletes them. Where ocean currents, climate and geography force deep water to the surface, primary production increases dramatically with the introduction of higher levels of mineral nutrients. This production supports entire food chains. This upwelling is caused by both geographic and climatic factors. It produces areas in the ocean where the fisheries are particularly rich, and thus, are of high interest to humans.

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Temperatures

Complicating this issue of heat storage in the oceans is the fact that the oceans are not really just one big monolithic pool of water. From the surface, we tend to focus on the separations of the oceans in geographic terms; the Atlantic is distinct from the Pacific is distinct from the Arctic, and so on. From a heat reservoir and a "parcels of water with shared characteristics" perspective, a major distinction is between the surface ocean and the deep ocean.

In the tropics through mid-latitudes, sunlight provides a lot of heat to the uppermost layers of the ocean. However, this warming sunlight only penetrates to depths of a few tens of meters. The stirring action of wind-driven surface waves and the tides keeps the uppermost layers of the oceans well mixed, so the heat provided by the Sun is effectively distributed throughout the top few hundred meters of ocean water. However, the deeper ocean, which contains about 90% of all ocean water, does not mingle much with the surface layers. Sea surface temperatures range from slightly below freezing near the poles to an annual average near 30° C in the tropics. Deep ocean temperatures span a much more narrow range, between about 0° C and 4° C, and are nearly uniform throughout the world's oceans. A fairly sharp transition between warmer surface waters and the colder deep waters, called the thermocline, exists at depths of a few hundred meters throughout most of Earth's oceans.

What significance does this separation between surface and deep ocean waters have for climate change? Since the surface layer is exposed to the atmosphere, a warming atmosphere can effectively transfer heat to the upper layers of the ocean. Although water, due to its relatively high "thermal inertia", heats more slowly than air, we can expect that increasing air temperatures will lead to warmer surface waters over time scales of years to decades.

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Of course, although surface and deep waters are not well-mixed, they do mix gradually over longer timescales. A major ocean circulation system called the thermohaline circulation (Global Ocean Conveyor Circulation) plunges cool surface waters into the deep ocean, mostly in the North Atlantic and around Antarctica. The thermohaline circulation eventually raises some of the deep ocean water to the surface; mostly in the Pacific but also in the Indian Ocean. This round trip is not a quick one though; it generally takes at least a couple hundred years, and can last as long as 1,600 to 2,000 years for water that makes the longer journey to the Pacific.

Heat and dissolved chemicals (including carbon dioxide from the atmosphere that dissolves into sea water at the surface) do not necessarily have to travel with a parcel of water as it makes the long journey to the deep ocean and back, but in many cases they do. So warming (or cooling) of the deep ocean will likely occur on much longer timescales than is the case for the ocean's surface layers, and on much, much longer timescales than for the atmosphere. Global warming will heat the deep ocean very slowly; but the deep ocean's recovery once we "fix" the problem (presuming we do!) will also be extremely gradual, lasting many human generations. Effects that began early during the industrial revolution in the 1800s are now being felt in the deep oceans. This time lag between climate forcings and the reactions of Earth systems to those forcing is a major feature of many aspects of global climate change that is of concern to scientists. Policies that attempt to prevent or account for further impacts from climate change need to take such lag times into account.

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Salinity

Dissolved salts in ocean water make it taste salty. Fresh water has dissolved salts in it too, but not nearly as many as ocean water! These dissolved salts can come from the land, precipitation, or the atmosphere, and are particles that have completely mixed in with the water.

Ocean water is about 3.5% salt. That means that if the oceans dried up completely, enough salt would be left behind to build a 180-mile-tall, one- mile-thick wall around the equator! And more than 90 percent of that salt would be sodium chloride, or ordinary table salt. The oceans sure contain a lot of salt.

All over the globe and from the top of the ocean all the way to the bottom of the ocean, salinity is between ~33-37 ppt or psu (average salinity of the ocean is 35 ppt). The image shown on this page shows salinity measured at the surface of the ocean across the globe. Almost the entire ocean is colored some shade of orange, corresponding to a salinity measurement around 33-36 ppt or psu.

The oceans are naturally salty. Life in the oceans has adapted to this salty environment. But, most creatures that live in the ocean could not live in fresh water. When the salty waters of the ocean meet fresh water, an estuary is formed. This is a special environment where some creatures have learned to adapt to a mixture of fresh and salt water. Humans have the responsibility to make sure their actions are not causing damage to these special environments where life thrives.

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Density

The density of pure water is 1000 kg/m3. Ocean water is more dense because of the salt in it. Density of ocean water at the sea surface is about 1027 kg/m3.

There are two main factors that make ocean water more or less dense than about 1027 kg/m3: the temperature of the water and the salinity of the water. Ocean water gets more dense as temperature goes down. So,

the colder the water, the more dense it is. Increasing salinity also increases the density of sea water.

Less dense water floats on top of more dense water. Given two layers of water with the same salinity, the warmer water will float on top of the colder water. There is one catch though! Temperature has a greater effect on the density of water than salinity does. So a layer of water with higher salinity can actual float on top of water with lower salinity if the layer with higher salinity is quite a bit warmer than the lower salinity layer.

The temperature of the ocean decreases and decreases as you go to the bottom of the ocean. So, the density of ocean water increases and increases as you go to the bottom of the ocean. The deep ocean is layered with the densest water on bottom and the lightest water on top. Circulation in the depths of the ocean is horizontal. That is, water moves along the layers with the same density.

The density of ocean water is rarely measured directly. If you wanted to measure the density of ocean water, you would have to collect a sample of sea water and bring it back to the laboratory to be measured. Density is usually calculated using an equation. You just need to measure the salinity, temperature and pressure to be able to find density. These measurements are often made with a CTD instrument, where the instrument is placed in the ocean water from a ship or a platform.

Pressure

Even though we do not feel it, 14.7 pounds per square inch (psi), or 1kg per square cm, of pressure are pushing down on our bodies as we rest at sea level. Our body compensates for this weight by pushing out with the same force.

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Since water is much heavier than air, this pressure increases as we venture into the water. For every 33 feet down we travel, one more atmosphere (14.7 psi) pushes down on us. For example, at 66 feet, the pressure equals 44.1 psi, and at 99 feet, the pressure equals 58.8 psi.

To travel into this high-pressure environment we have to make some adjustments. Humans can travel three or four atmospheres and be OK. To go farther, submarines are needed.

Animals that live in this watery environment undergo large pressure changes in short amounts of time. Sperm whales make hour-long dives 7,380 feet (2,250 meters) down. This is a pressure change of more than 223 atmospheres! By studying and understanding how these animals are able to withstand great pressure changes, scientists will be able to build better tools for humans to make such journeys.

Oceanic Oxygen

Oxygen at the surface is frequently high in the ocean, and the deep sea has abundant oxygen in its cold water. A layer in between, in the mid-water or mesopelagic region, at around 500 m may be low in oxygen. This oxygen minimum layer creates interesting problems for mid-water species that are solved by both behavioral and biochemical adaptations to low oxygen.

Recent Discoveries

In 1977, near the Galapagos Islands in the Pacific Ocean, oceanographers discovered deep sea vents and communities of organisms never seen before. These hydrothermal vents are located in regions where molten rock lies just below the surface of the seafloor, producing underwater hot springs. Volcanic "chimneys" form when the escaping superheated water deposits dissolved minerals and gases upon coming in contact with the cold ocean water. Around these vents are bacteria that obtain energy from the oxidation of hydrogen sulfide escaping from the vents—a process called chemosynthesis.

These bacteria (primary producers) are then used as food by tube worms, huge clams, mussels, and other organisms (primary consumers) living around the vents. Since these

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communities are not photosynthesis-based like all other biological communities, they may provide clues to the nature of early life on Earth.

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Activity: All That Glitters… DuratioN: 2 hours

OBJECTIVES

Students will experiment with a model of what happens to light and colors as one descends into the ocean.

Students will describe at least two adaptations to low or no ambient light on the part of deep-sea organisms.

MATERIALS For the teacher:

3‖ x 5‖ card with 1-in slit cut in middle

35 mm slide projector

Prism

Glow stick (from dive shops, fishing tackle or sporting goods stores or ―dollar‖ stores)

One hole punch

Optional: vial of ostracods from Carolina Biological Catalog: GR-20-3430; $32.80 Per student:

Deep sea dive goggles made with: Blue plastic - blue plastic report covers or blue color filter gel plastic; depending upon the ambient light in your room, you will need 4-8 strips of plastic per goggle. Each strip should be about 8.5‖ x 3‖. Blue color filter gels are available from Stage Light Louisiana LLC, phone (540) 818-1880; SLD Lighting, phone 800-245-6630, www.sldlighting.com; or check your local yellow pages under ―Theatrical and Stage Lighting Equipment.‖ Ask for Roscolux #80 primary blue, Lee #079 just blue, or Gam #850. These sheets are 24‖ x 20‖, producing 21 strips per sheet. Six sheets should produce 31 4-layer goggles. Blue plastic report covers or index dividers are available from office supply stores. Office Depot Insertable Index Dividers Item #455-801 is one source for the color of blue needed for this activity.

Elastic - about 12‖

One ―regular‖ paper clip

One ―binder‖ paper clip (the black and silver kind used for thick bundles of paper) Per student pair:

in red, orange, yellow, green, blue, black/dark brown, Sheet of black construction paper or black craft foam

―Color in the Sea‖ Student Handout chart

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BACKGROUND INFORMATION This activity allows students to explore the nature of light, ask what happens to light as it passes through the ocean and speculate on how deep-sea animals deal with living in the dark. During the 2002 South Atlantic Bight Expedition, Islands in the Stream, two scientists from the Harbor Branch Oceanographic Institution, Dr. Tamara Frank and Dr. Edith Widder, studied vision and bioluminescence in the deep sea. Of particular interest were animals with large eyes that live on the sea floor in the aphotic zone. Many animals that swim in open water (pelagic) in the mesopelagic or twilight zone have large eyes relative to their body size. Large eyes capture what little light is available. As depth increases below the mesopelagic, eye size in many organisms decreases. For example, two species of bristlemouths, Gonostoma denudatum, a midwater fish, and Gonostoma bathyphilum, a deeper water fish, have different eye sizes. The midwater species has much larger eyes. The deep water species has much smaller eyes—the result you would expect if eyes had no value in the total absence of light. However, an enigma exists. Many animals living on the deep-sea floor sea have huge eyes! One possible value of vision where there is no ambient light is that some deep-sea organisms make their own light—they are bioluminescent.

PROCEDURE Teacher Prep

1. Cut a thin slit, just a few millimeters wide and about an inch long, in the card. 2. Tape a small piece of blue plastic over the light source. Ask students to note

what color is projected (blue). Make sure that students understand that the blue plastic blocks part of the spectrum by absorbing colors of light other than blue.

3. Place prism in beam of light and practice rotating prism to project the colors of the spectrum on the movie screen or white wall.

4. Cut the blue plastic into strips approximately 8.5 inches long by 3 inches wide. 5. Punch a hole in the middle of one end of every strip of plastic. Thread 4-8 sheets

of plastic through the regular paper clip. Tie one end of the elastic to this paper clip. Tie the other end of the elastic to one of the silver ends of the binder clip.

6. Separate felt or foam squares by colors so that brown), red, orange, yellow, green and blue.

Procedure

1. Ask your students to tell you what they know about light. Dim the lights and project a visible spectrum on the wall. Have the students write down the colors they observe in the order they see them in the spectrum. Review colors, absorption and reflection.

2. Tape a small piece of blue plastic over the light source. Ask students to note what color is projected (blue). Make sure that students understand that the blue plastic blocks part of the spectrum by absorbing colors of light other than blue.

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3. Challenge the students to observe what the underwater world looks like by using Deep Sea Diving Goggles. Pass out the black paper or craft foam, Deep Sea Diving Goggles, and foam or felt squares to each pair of students.

4. Explain that the black piece of paper represents the darkness of the deep sea. Spread the felt or foam squares on the black paper.

5. Use only one layer of the Goggles to observe the colors of the foam or felt squares. Add another layer and observe. Continue adding layers, simulating what it looks like to go deeper into the ocean. What happened with each color? The blue plastic enables students to see how colors appear in deeper water. The blue plastic filters out other colors just as water absorbs them. Students should observe that the color black disappears first, followed by red, then orange, then yellow. Distribute the ―Color in the Sea‖ Student Handout chart to each student group if you would like them to quantify their observations.

6. If they were fish wishing to hide in the mesopelagic twilight zone, what colors would be the best camouflage? Black and then red

7. Introduce bioluminescence using the glow stick. Demonstrate ―turning it on‖—shaking it makes it brighter as you are mixing the chemicals that produce light when they react. Ask the students for their experiences with bioluminescence: fireflies are the most common among eastern US students. Black light posters are fluorescence—a very different process. Observe the glow stick with the goggles on. How might deep-sea species use the light they make? Discuss counter-illumination, finding a mate, finding prey, attracting prey and startling predators by blinding them. What color would be the most effective for bioluminescence —blue as it penetrates water most easily.

8. You may wish to go into detail about the chemical nature of bioluminescence if your students have sufficient foundation. If you have the ostracods, place three to five in your palm. Add two drops of water and crush the dried animals using a finger. Show your palm; a bright blue results. When you crush the dried animals, two chemicals mix to create blue light.

9. Visit the South Atlantic Bight OE expedition on the web or the OE CD and see what the scientists were studying about bioluminescence.

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Activity: Light at the Bottom of the Deep, Dark Ocean

Duration: 2 hours

OBJECTIVES

Students will experience the impact of bioluminescence on finding food and becoming prey in the deep ocean.

Students will be able to describe the positive and negative values of being able to produce light.

MATERIALS For the class:

Long table in open space that can be made dark; push several tables together, pull down shades and turn off lights; cover table with black paper

Red, orange, yellow, green and blue 2 square cm. pieces of craft foam or felt. For each student:

Deep Sea Dive Goggles from All That Glitters; use hole punched at each end and tie 18-inch strings (or use paper clips and very long rubber bands) in holes so they may be worn hands free as a mask

Small flashlight or glowstick

Student worksheet

Snack-size plastic bags

BACKGROUND INFORMATION This exercise should be preceded by All that Glitters….It uses some of the same equipment and assumes that the students have an understanding of light, light in the ocean and bioluminescence. The students should have already worked with colors in the ocean. Deep-sea fish use color to help hide—they may be camouflaged. Red is good camouflage since red light disappears in shallow water. Black is also useful in the dark. In this exercise students will apply what they have learned about color. Finding food in the deep sea may be aided by use of bioluminescence—fish may have light organs that illuminate the surrounding water, revealing prey. On the other hand, when a fish lights up looking for prey, it exposes itself to predation by a larger fish. Bioluminescence is an adaptation to life in the deep sea. It may be useful for communication among members of a species, for attracting a mate, it may illuminate prey or attract prey, and it is used for counter-illumination to obscure its outline against the lighter surface. In this exercise, students will be deep-sea fish with light organs that

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are used to illuminate prey so that they can eat them. They may also eat what they can find in the dark. The teacher will be the large predatory gulper eel.

PROCEDURE

1. The day before this exercise, remind the students of what they learned in All that Glitters… about light and color in the deep ocean. Suggest that they dress in clothing that would make good camouflage in the deep sea for the next class. Red or black would be best, with long sleeves and good coverage, but do not tell them this—leave it up to them. Students wishing to go to extremes might choose to bring a face covering ski mask. For this activity they will be modeling the behavior of deep-sea fish that feed using bioluminescence.

2. To do this exercise, select the first set of students; give them flashlights, plastic bags and goggles. Spread felt or foam squares thinly on the black paper on the tabletop and tell them this is their food. They must find it in the dark, wearing the goggles. They are fish living in deep water where there is very little light. They may use the flashlight, their bioluminescent organ, to look for food, but whenever it is on, you may tag them because they are visible to a predator—you. When you tag them, a gulper eel has eaten them. They may only use one hand to collect food—using their thumbs and forefingers to pick up one item at a time and place it in their bag. Students not playing will watch to make sure the rules are followed. Anyone being rowdy loses.

3. With goggles in place, dim the lights and let the students begin feeding. If they can see the prey, they may feed without the light, but the light will illuminate almost invisible items. Play until you have tagged about 1/2 of the students. Repeat with another group. The students may keep their bags when tagged. They just have to stop eating.

4. Have the students evaluate the contents of their bags for colors selected. Add up all the felt or foam squares eaten by color versus those left on the table by color.

5. Allow all students time for reflection by having each student fill out the Student Worksheet. Then have a class discussion about the questions.

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Activity: Density Currents Duration: 2 Hours

Objective

Students work in small groups to experiment with currents caused by temperature variations that simulate the origins and flow of polar bottom currents.

Materials

rectangular container (glass dish, plastic shoebox or storage container)

4 small thermometers (to fit in plastic container)

cup (paper or plastic) with pinholes in bottom

tape

food coloring

crushed ice

eye dropper

paper, small approx. 1/2‖

tap water

Procedure (see illustration - next page)

1. Divide class into small groups of 3 - 4 students. Have one student get supplies and equipment.

2. Students tape cup in one corner of rectangular container, about one inch from the bottom.

3. Tape 4 thermometers in bottom of dish, all oriented in same direction with equal spacing.

4. Add water to the container, so the bottom of the cup is covered. Let water settle. 5. Record the temperature on all 4 thermometers at the start of the experiment, or

time = 0. 6. Place ice in the cup and add 10 drops of food coloring. 7. Record the temperatures again every 5 minutes for ½ hour on the data sheet. 8. Observe what happens by looking though the side of the dish at table level.

Record your observations by making a small sketch or diagram of what you see, and explain what you think causes what think causes this.

9. NOTE: If you can not see a bottom current, heat the corner opposite the ice by placing a beaker of hot water in the dish.

10. At the end of 30 minutes place a small piece of paper (1/2 inch square) on top of the water in the corner opposite the ice.

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Questions

1. The paper moves in which direction? (toward ice) ____________________________________________________________________________________________________________________________ 2. What does the paper represent, a surface or deep current? (surface) ____________________________________________________________________________________________________________________________ 3.

the ice) ____________________________________________________________________________________________________________________________ 4. Which thermometer changed the fastest? (nearest the ice) ____________________________________________________________________________________________________________________________ 5. ____________________________________________________________________________________________________________________________ 6. ____________________________________________________________________________________________________________________________ 7. Explain what happened to cause the changes in the 4 thermometers’

temperatures. (cool water sank and flowed across the container while the warm surface water flowed toward the cup.)

____________________________________________________________________________________________________________________________ 8. What can we learn from the movement of the colored water? (It traces the movement of the water current across the bottom.) ____________________________________________________________________________________________________________________________ 9. What does your cup of ice imitate in the real world? (polar sea ice) ______________________________________________________________ ______________________________________________________________

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10. How does cooling affect the density of water? (Cold water is denser than warm water.) ____________________________________________________________________________________________________________________________ 11. Where would you find cold water currents in the ocean? (Moving away from the polar regions in the deep ocean)

___________________________________________________________________________

_______________________________________________________________

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Activity: Finding the Deep Water Masses of the Atlantic Ocean

Objective

Students will be able to describe the role of density in driving deep ocean currents and the density layers of the ocean.

Materials

water masses data table

temperature - density - salinity graph

water masses worksheet (on cross section of the Atlantic)

Atlantic ocean map and cross section

Procedure

1. Complete the Water Masses Worksheet and Water Masses Data Table as instructed.

2. Start by matching the temperature and salinity for each water mass to find the density ( st ) using the Temperature-Density-Salinity graph. Record these densities on your Water Masses Worksheet (Cross Section of the Atlantic Ocean).

3. Next, on the Water Masses Data Table, match the latitude, temperature and salinity to find the density ( st ) and the name of each water mass.

4. Last, fold the page with the Atlantic Ocean Map and Atlantic Ocean Cross Section 90O to get a three dimensional view of the water masses and their origins. This will help you answer the Evaluation questions on the next page.

Key to Water Mass Abbreviations NADW = North Atlantic Deep Water MI = Mediterranean Intermediate SW = Surface Water AAIW = Antarctic Intermediate Water AABW = Antarctic Bottom Water

Finding the Deep Water Masses from the Atlantic Ocean

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Questions

If a person had a very long fishing line, why might it be possible to catch an Antarctic species of shark while fishing at the Equator?

_____________________________________________________________________________________________________________________________________

Wind driven surface currents travel at approximately one kilometers per hour, while density driven deep ocean currents travel much slower, about one meter per hour. How long would it take Antarctic Bottom Water to travel to the North Atlantic sample site at 45ON, approximately 9,000 km from its Antarctic source area?

___________________________________________________________________ ___________________________________________________________________

What relationships can you describe between water temperature and salinity at the 0O sample site?

______________________________________________________________________________________________________________________________________

What happens to the water density at the 45ON sample site? ______________________________________________________________________________________________________________________________________

From the Temperature-Density-Salinity Graph, what happens to the density of seawater at temperature increases? As the temperature decreases the density of the seawater does what?

______________________________________________________________________________________________________________________________________

What factor(s) increase sea surface water density at high latitudes? _____________________________________________________________________________________________________________________________________

What factor(s) cause the density of the surface water in the low latitude regions to increase?

______________________________________________________________________________________________________________________________________

Explain why density driven circulation in the ocean depths is caused by the interaction of the atmosphere and the ocean.

______________________________________________________________________________________________________________________________________

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Why the sun is considered the source of energy for driving the density circulation in ocean depths? Explain

_________________________________________________________________________________________________________________________________________________________________________________________________________

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Activity: Aquatic Autobiography

Duration: 3 Days

Materials

Index Cards Poster board or Butcher paper Art supplies Access to library or computer with internet access

Procedure

1. Give each student an index card and ask them to write down their definition of a habitat.

Collect the cards and read a few of them out loud. Ask students if any of those definitions are correct.

2. Give students the following definition and example of habitat (you can read it or ask for a volunteer):

An animal’s habitat is the place where it lives, finds food, defends itself from predators, finds a mate and reproduces. Most animals confine their activities to a particular kind of habitat where they are most successful at fulfilling their needs. For example … oysters populate areas where there is a suitable flow of oxygen-filled water, an abundant supply of plankton to serve as a food source, and a hard surface to settle on.

3. Remind students of the definition of the word adaptation. Reread the definition and ask students to identify the adaptations that

would allow an oyster to survive in the habitat described. 4. Introduce the different ocean zones with the class

Be sure to include the characteristics of each zone and example of the types of organisms that live in each.

Have students ID some of the special adaptations organisms would need to survive in each zone.

5. Break students into groups of 3-5 students. Explain to students that they will have the opportunity to investigate further investigate an organism from one of the ocean zones.

Assign each group a zone to focus on Give each group some time to do some research and to select an

organism from that zone 6. Students should address the following questions as they continue their research:

What does the organism look like? What are some special features of the assigned ocean zone/habitat? What are some of the organism’s special characteristics or adaptations?

How does it eat? How does it protect itself? Etc.

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What are the different life cycle stages of the organism? Does the organism live in this zone for its entire life? If not, where else does it go? How do its adaptations change based on its life cycle?

What else is unique and interesting about this organism? 7. Once groups have completed their research, ask each group to write an

autobiography for their organism. They should include life history information, as well as daily interactions

with abiotic and biotic factors in their habitat. Students should create a book or poster board detailing their

autobiography. 8. Ask each group to present their final project.

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Activity: Temperature Changes: Atmosphere & Ocean

Duration: 1 hour

Objective

Students observe temperature differences of water and air in sunlight and darkness.

Materials 2 thermometers

2 quart- size jars with lids

water

Procedures

1. The teacher puts a thermometer in each jar, fills one jar with water and caps both jars. Label the water jar ―ocean‖ and the empty jar ―atmosphere.‖ Record the temperature of each on the board. Place the jars next to each other in the sunlight for about ½ an hour.

2. Ask the students: What do they think will happen in each jar? (write in journal)

3. Which thermometer will rise quicker? Why?

4. After ½ hour record the temperatures on the board next to the first temperatures.

5. Ask the students: Which jar is hotter?

6. Which jar showed the greatest change in temperature?

7. The teacher now places the jars in the shade for about ½ hour.

8. Ask the students: Which container will cool the fastest? What do you think?

Why? Chart data in journal.

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9. After ½ hour record the temperatures. Find the difference between the new and previous high temperature of each jar. Have students generalize about what is

happening to the atmosphere and ocean. (Water heats and cools slower than air.)

Questions

1. In the winter, would the average temperature of the ocean or the air be warmer? Why? (Winter has warmer ocean temperatures than air temperature).

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

__________________________________________________________________________

2. How would the summer ocean temperature differ from the air temperature? (Summer has warmer air temperature than the cooler ocean temperature.)

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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Activity - Deep Ocean Currents

Duration: 1 hour Objectives

Students observe the interactions of different temperatures of water using colored ice and a thermometer and then compare the results with global ocean current solar heating.

Materials

world maps

activity sheets

clear glass

water – cold tap

water – hot tap with 2 drops of red food coloring

ice cubes frozen with 15 drops of green food coloring

aquarium thermometer

spoons

Procedures 1. Each group of 3-4 students obtains 1 clear glass filled ¾ full of cool tap water. 2. Students place an aquarium thermometer in the glass. Wait 2 minutes, then record the temperature. 3. Students obtain an ice cube and place in the water, using a spoon. 4. Students observe the glass, draw the glass, and explain what is happening. 5. Wait 2 minutes and record the temperature. 6. Students obtain ¼ glass of hot colored tap water and gently pour the water down the inside edge of the glass. Don’t disturb the rest of the water. 7. Students observe the glass, draw the glass, and explain what is happening. 8. Wait 2 minutes and record the temperature.

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Questions Was the colored water moving away from the ice cube colder or warmer than the

water in the glass? (cooler) ____________________________________________________________________________________________________________________________________________

Was the warm colored water that was added colder or warmer than the water in the glass? (warmer)

____________________________________________________________________________________________________________________________________________

Where would floating ice be found in the ocean? (near the poles) ____________________________________________________________________________________________________________________________________________

Where would cold water be found? ( poles and in the deep ocean) ____________________________________________________________________________________________________________________________________________

Where would cold water flow in the ocean? (at the bottom) Why? ____________________________________________________________________________________________________________________________________________

Where would you expect to find the warmest waters in the ocean? (near the equator and at the surface)

____________________________________________________________________________________________________________________________________________

Where would warm moving water flow in the ocean? (near the surface) Explain. __________________________________________________________________________________________________________________________________________________________________________________________________________________

Which direction would cold water move in the ocean? (down and toward the equator where it is heated)

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__________________________________________________________________________________________________________________________________________________________________________________________________________________

Which direction would warm water move in the ocean? (up and toward the poles, where it cools.) _____________________________________________________

Scientists have found that water in the ocean is well mixed. How do differences in temperatures mix ocean waters? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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Worksheet: Deep Ocean Currents Temperature of cool tap water ______________________________________ What happens after adding the ice cube? Describe in words and draw a picture of the glass. Temperature of water with the ice cube in it ___________________________ What happens after adding the warm water? Describe in words and draw a picture of the glass? Temperature of water with warm water added _________________________

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Resources http://www.seasky.org/deep-sea/ocean-layers.html http://www.scienceclarified.com/Mu-Oi/Ocean-Zones.html http://weirdnewsfiles.com/tag/ocean-glow/ http://www.onr.navy.mil/focus/ocean/water/pressure1.htm http://www2.ec.gc.ca/chocolate.en.experiment_e.htm http://oceanexplorer.noaa.gov/edu/curriculum/section5.pdf http://www.msc.ucla.edu/oceanglobe/pdf/climatecurents/currentsentire.pdf http://www.cutter.com/osir/primer.htm www.wikipedia.com All images are taken from Google Images.