The Ocean Chapters 18 & 19

Importance of the ocean H.W. pg 517 ques. 1-4 The oceans are important sources of food, energy and minerals for many living organisms. Energy sources like coal and oil can be found underneath the ocean floor. 1/3 of the worlds table salt is taken from the oceans salt water. They also make the transportation of goods, by ship, possible.

Origin When the Earth first formed, its surface was mostly volcanoes and cooled volcanic rock. When all of these volcanoes erupted, they released a lot of water vapor into the atmosphere. Over millions of years this water vapor gathered in the atmosphere and condensed to form torrential rains which formed our oceans today.

Composition The oceans contain dissolved gasses like oxygen, carbon dioxide, and nitrogen. Waters salinity is the measure of dissolved salt in seawater. Today's average is 3.5% of the oceans water is salt. The oceans also contains many dissolved salts along with other elements like calcium, magnesium, and sodium.

Desalination Because the demand for freshwater is so high, scientists are trying to come up with technology to take the salt out of water. They are doing so by using a desalination plant. This is a large peaked roof building that is filled with saltwater from oceans. The room is heated so the water evaporates and condenses on the ceiling, once it condenses, it then drips down the ceiling as freshwater into drums.

Ocean currents An ocean current is a mass movement, or flow of ocean water. They are like rivers within oceans. Surface currents move water horizontally and are powered by winds. These winds force the currents to move in a circular motion. These currents only move the upper few hundred meters of ocean water.

Ocean currents Warm currents are shown with red lines and cold ones with blue lines. West coast currents of the U.S. originate at the poles and move down past Cal. Surface currents that flow along the East coast of the U.S. originate near the equator and are warmer.

Upwelling and Density currents Upwelling is the vertical circulation of ocean water. This brings deep, colder water from the bottom of the ocean, closer to the surface. This water brings with it many nutrients from the ocean floor and promotes a healthy ecosystem for marine organisms. A density current is when a mass of seawater becomes more dense than the surrounding water and sinks beneath less dense seawater. H.W. pg 523 ques. 1-4

Waves and Tides A wave is a rhythmic movement that carries energy through matter or space caused by the varying speeds of winds. The crest is the highest point of a wave and a trough is the waves lowest point. The distance between to adjacent crests equals a wavelength. The height of a wave is the difference between the crest and the trough. The amplitude of a wave is half of the waves height.

Wave movement Waves makes water appear to move forward, but unless the wave breaks onto a shore, all water returns close to its original spot after the wave passes. Only the energy in the wave is moving forward not the water. When a wave does crash onto a shore that wave is called a breaker. This is the collapse of a wave is what propels a surfer back toward the shore.

Tides Tides are the rise and fall of sea level. They are created by giant waves that are produced by the gravitational pull of the sun and moon. Water levels moves out at low tide and rise again at high tide. Tidal range is the difference between high and low tide ocean levels. Oceans react to the pull b/w the earth and moon. 2 budges of water are always forming when the moon rotates the earth

Tides and the moon Oceans react to the pull b/w the earth and moon. 2 bulges of water are always forming when the moon rotates the earth. One is going to be where the moon is closest to the earth and the other on the opposite side. These bulges cause high tides where the moon is closest to the earth, and the areas of the earth that the moon is not over at that time experience low tides.

Spring and Neap tides When the sun, moon and earth are all lined up it causes more gravitational pull and creates spring tides, which make high tides higher and low tides lower than normal. When the sun, earth, and moon are at right angles to each other they cause neap tides, which give lower high tides and higher low tides than normal. H.W. pg 538 1-15 on loose leaf.

The Sea Floor Ocean basins are low area of Earth filled with water, that have many different features. The continental shelf is a feature, which is the gradually sloping end of a continent that extends under the ocean. The continental slope is where the ocean floor drops steeply and extends from the outer edge of the continental shelf down to the ocean floor.

Ridges and Trenches Mid-ocean ridges are found at the bottom of all ocean basins, and is an area where new ocean floor is formed. New ocean floor is created by plates separating, and hot magma from the earth’s core forming new ocean crust through a process called sea floor spreading. This new floor forms along new ocean ridges. A trench is a long narrow steep sided depression where one crustal plate sinks below another.

Life in the Ocean The ocean is home to life forms of all Kingdoms, that go through many different life processes. Photosynthesis is the process in which organisms can make their own food with the use of a green pigment called chlorophyll. This process uses carbon dioxide, water, sunlight to produce food for the organism and energy in the form of ATP and oxygen which other organisms like fish and other animals use.

Life in the Ocean Chemosynthesis involves using sulfur or nitrogen as an energy source instead of the sun to produce food. Bacteria use sulfur compounds and live near hot sulfur vents that spew extremely hot water. These bacteria serve as food for many organisms like clams, crabs and shrimp.

Ocean Life Forms Plankton from the Kingdom Protista are very important to the food chain of the ocean. They are producers that are one celled and drift with the ocean currents. Ex: Diatom. Animals that swim with the current instead of drifting with it are called nekton. Plants or animals that live on the seafloor are called benthos. Snails, sea urchins and crabs. H.W. pg. 568 1-15 on loose leaf.

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