The Ocean Chapters 19-21

The Water Planet The global ocean contains 97% of all of the water on Earth. The global ocean is divided into five major oceans: Atlantic Pacific Indian Arctic Southern Oceans

Pacific Ocean The Pacific Ocean is the largest ocean on Earth. It contains more than one-half of the ocean water on Earth. It is also the deepest ocean with an average depth of 4.3 km.

Oceans The next largest ocean is the Atlantic Ocean. The third largest is the Indian Ocean. They both have an average depth of about 3.9 km.

Seas Seas are smaller than oceans and may be partially surrounded by land. Examples are Mediterranean Sea Arabian Sea Caribbean Sea

Ocean Exploration Oceanography- the scientific study of the oceans Some ancient civilizations studied the oceans. Modern oceanography didn’t start until the 1850s.

Oceanography Matthew F. Maury published observations of the ocean in 1855 as one of the first textbooks. From 1872-1876, a team of scientists aboard the HMS Challenger took water temps at great depths, samples of ocean water, sediments, and thousands of marine organisms.

Modern Oceanography JOIDES Resolution was the largest and most sophisticated scientific drilling ship in the beginning of the 21st century. The Japanese ship CHIKYU is the most advanced now in use.

Sonar A system that uses acoustic signals and returned echoes to determine the location of objects or to communicate. Stands for Sound Navigation and Ranging Scientists use the information to make maps and profiles of the ocean floor.

Submersible Underwater research vessels Piloted by people (bathysphere) Self-propelled (bathyscaph) Submarine Robots

Submersibles Make discoveries about the ocean Take photographs Collect mineral samples Allow oceanographers to study for long periods of time.

Ocean Floor Sediments Core samples are taken of deep floor sediments Sediments can be inorganic or organic A lot of sediment is created originally by living organisms- biogenic Chemical deposits that crystallize are called nodules- they are composed mainly of oxides

Physical Classification of Sediment Two main types are Muds- very fine silt and clay sized particles of rock Ooze Calcareous ooze is made of calcium carbonate Siliceous ooze is made of mostly silicon dioxide which comes from the shells of radiolarians and diatoms.- Mostly in Antarctica.

Salinity of Ocean Water Salinity is a measure of the amount of dissolved salts and other solids in a given liquid Salinity is measured by the number of grams of dissolved in 1,000 g of ocean water. Ocean is about 3.5% salts Fresh water is less than .1%

Salinity The global ocean is an average of 34.7% The Red Sea is about 40%. It is due to the hot, dry climate around the Red Sea, which causes high levels of evaporation.

Temperature of Ocean Water Temp varies depending on depth and location. The range of ocean temps depends on the amount of solar energy an area receives and by the movement of water in the ocean.

Color of Ocean Water Substances or organisms in ocean water, such as phytoplankton, can effect the color of the water. Phytoplankton reflect green light. Studying variations in the color of the ocean, scientists can determine the health of the ocean.

Tides and Waves Waves have two basic parts- a crest and a trough The wavelength is the distance between two consecutive crests. The wave period is the time required for two consecutive wave crests to pass a given point Speed= wavelength/ wave period

Wave A wave is a disturbance that carries energy through matter or space. A medium is the matter through which a wave travels. Air, water, etc.

Waves When a wave meets a boundary, the wave bounces back. When a wave passes the edge of an object or passes through the opening, the wave bends. A wave also bends when it passes from one medium to another at an angle.

Parts of a Wave

Reflection, Diffraction, and Refraction Reflection- is the bouncing back of a wave when it meets a surface or boundary Diffraction- the bending of waves as they pass an edge Refraction- the bending of waves when they pass from one medium into another. All waves are refracted at an angle.

Waves

Interference When several waves are in the same location, they combine to produce a single, new wave that is different from the original waves. Two types: Constructive interference- adds the total intensity Destructive interference-Subtracts the intensity

Doppler Effect Example: You are standing outside and an ambulance passes by. The pitch of the siren goes from higher to lower. Why? An observed change in the frequency of a wave when the source or observer is moving.

Ocean Currents A horizontal movement of water in a well-defined pattern, such as a river or stream. Surface currents Deep currents

Ocean currents Factors influencing currents: Wind-transfers kinetic energy to the water- Global wind belts effect the direction of the wind Location of continents- Continental barriers Coriolis effect- Earth’s rotation also effects the currents Causes gyres or a huge circle of moving ocean water found above and below the equator

Major Currents Equatorial Countercurrent Antarctic Circumpolar Current (West Wind Current) Gulf Stream that widens into North Atlantic Current

Ocean Currents Regulate the climate in the areas around them Help distribute nutrients and species around the world Help prevent the ocean water from being stagnant

Behavior of Tides Because there are two tidal bulges, most locations in the ocean have two high tides and two low tides daily Spring Tides are when the tides are the strongest- New moon and full moon Neap tides- first and third quarter moon/ weakest tides

Tidal Variations Tidal patterns are influenced by the size, shape, depth, and location of the ocean basin in which they occur. They are also affected by tidal oscillations. Slow rocking motion of the ocean water that occurs as the tidal bulges move around the ocean basins.

Tidal Currents When the tide flows toward the coast it is a flood tide. When the tidal current flows toward the ocean it is called an ebb tide. When there is no tidal current, it is called a slack current.