Exploring the Ocean

Earth’s Oceans Oceanographer – someone who studies the ocean Cover 71% of the planet Contain 97% of Earth’s water Source of fresh water for all living things Fresh water escapes as water vapor; salts left behind Water vapor in the atmosphere condenses to form clouds and precipitation Part of the water cycle, some runs into rivers, streams and becomes ground water and some back into the ocean

4 Major Oceans Pacific Ocean Atlantic Ocean Indian Ocean Arctic Ocean Largest ocean; greater than Atlantic and Indian combined Deepest ocean; avg. depth nearly 4,000 m Atlantic Ocean second largest ocean; ½ size of the Pacific smaller Mediterranean Sea, Black Sea part of it Indian Ocean Third largest ocean Arctic Ocean Smallest ocean Most of it is covered by ice

How did the Oceans form? As the Earth’s atmosphere developed, the Earth was cooling. Sometime before 4 billion years ago, the Earth cooled enough for water vapor to condense and fall as rain. About 245 million years ago, one ocean formed called Panthalassa Atlantic and Indian formed first; about 180 million years ago Today, the plates move 1-10 cm per year…Atlantic Ocean getting bigger and Pacific Ocean getting smaller

Characteristics of Ocean Water Mixture of gases and solids dissolved (pg 332) Gases are Hydrogen, Nitrogen, and carbon dioxide Sodium chloride most abundant salt (NaCl) Salt acts like an antifreeze and keeps fresh water from freezing. Salinity = amount of dissolved salt in the water Measured in parts per thousand 1 kg (1,000 g) of ocean water contains about 35 g of dissolved solids on average so we say 35 parts per thousand avg. salinity

Factors that Affect Salinity Some areas of the ocean are saltier than others Water movement Slow moving water has higher salinity pg. 333 Coastal areas where major rivers flow into the ocean have lower salinity Climate: Hotter areas are higher salinity Less fresh water runs into the ocean in drier areas; heat increases evaporation rates.

Ocean Temperature Decreases the deeper you go (gets colder) 3 temperature zones Surface Zone Thermocline Deep Zone

Temperature Zones Surface Zone Thermocline Deep Zone Goes down 300 m Sun heats up to 100 m Thermocline Starts at 300 m to 700 m Temperature drops faster with depth than any other zone Deep Zone Starts at 700 m to bottom Temperature averages 2 degrees celsius

Surface Temperatures Vary with latitude and time of year Ranges from 1 degree C near the poles to about 24 degrees C at the equator Sun hits more directly at equator so it is always warmer In the summer, it hits more directly in Northern Hemisphere so oceans get warmer (colder in winter)

Density of Ocean Water Cold water is denser than warm water Salt water is denser than fresh water What happens when cold currents meet warm currents?

Three Main Groups of Marine Life Plankton Organisms that float at or near the surface Zooplankton, phytoplankton Nekton Free-swimming organisms Dolphins, whales, sea lions Benthos Organisms that live on the ocean floor Crabs, sea stars, worms, coral, sponges, seaweed

Benthic Environment Intertidal Zone Sublittoral Zone area located between low-tide and high-tide lines. Organisms need to be able to survive in and out of the water Sea anemones and starfish Sublittoral Zone Extends from low-tide line to the end of continental shelf more stable than the intertidal zone temperature, pressure and sunlight remain fairly constant corals

Benthic Environment (continued) Bathyal Zone – continental shelf to the abyssal plain lacks sunlight, plant life is scarce Sponges, sea stars, octopuses Abyssal Zone No plants and few animals Crabs, sponges, worms, sea cucumbers Hadal Zone Deepest Trenches Little known; found few species of clams and worms

Ocean Resources - Living Fishing Sonar, drift nets help fishing industries Overfishing concerns Fishing laws prompted fishing hatcheries Seaweed Harvesting Shrimp, oysters, crabs, mussels raised in enclosed areas along the shore. Thickens creams, jellies, and yes! Ice Cream

Ocean Resources – Non Living Oil and Gas Found in layers of impermeable rock Seismic equipment sends pulses through the earth to find areas Fresh Water Desalination – process of evaporating sea water to separate the salt Very costly – countries rely on rainfall Saudi Arabia - Middle East desert region – has one of the largest desalination plants in the world Minerals Manganese, iron, copper, nickel, cobalt, phosphates

Ocean Resources Tidal Energy and Wave Energy As tides rise and fall, and as waves crash on the shore, we can use the gravitational pull and force to create electricity Both are renewable resources of energy

Ocean Pollution Trash Dumping Sludge Dumping Non-Point source Millions of trash is dumped in the deep ocean U.S. started requiring hospitals to bury medical waste in sanitary landfills Sludge Dumping Raw sewage Non-Point source Everyday pollution from people Point source Oil spills Today, tankers are required to have double hulls

Take Action – Save our Oceans In 1989, 64 countries ratified a treaty that prohibited the dumping of mercury, cadmium compounds, certain plastics, oil, and radioactive wastes. Tough to enforce due to angencies lacking human resources and money. Citizens of many countries have demanded that their governments do more to solve the ocean pollution problem. Because of Public outcry in the U.S., more than $130 million each years goes to monitoring the ocean. People also volunteer to Adopt-a Beach and show up anually to clean up beaches in organized groups.

? Why does the Ocean have waves? What are the parts of a wave? How does water move in a wave? What happens when a wave hits a beach?

Define wave: Wave – a rhythmic movement that carries energy through matter or space. in the ocean, waves move through seawater.

Parts of a wave Wave height Wavelength Crest Crest Trough

Parts of a wave: Crest – the highest part of a wave. Trough – the lowest part of a wave. Wavelength – the distance between two adjacent crests. Wave height – the vertical distance between the lowest part and the highest part.

More wave words Frequency – the number of complete waves (or oscillations) that occur over a given period of time. Usually measured in cycles per second. Amplitude – half the wave height But Mr. Coleman, why do we have to learn vocabulary words that aren’t in the book? For the FCAT!

Most waves caused by wind Friction from the wind moving over the water causes the water to move along with the wind. If the wind speed is high enough, the water begins to pile up and a wave is formed.

How does water move in a wave? Some clues: When you were at the beach, you probably noticed that the edge of the water goes back and forth with the waves. If you float an object on the ocean, it stays roughly in one place. It is not pushed forward by the waves.

How water moves in a wave: Particles of water move around in circles. The farther below the surface, the smaller the circle. At a depth about equal to half the wavelength, the motion stops.

At the beach: Wavelength decrease and wave height increases as waves approach the shore. Constant Wavelength Waves drag against the bottom and wave length decreases

At the beach, part 2 As the wave slows, its crest and trough come closer together. The top of the wave is not slowed by friction and moves faster than the bottom. The top of the wave outruns the bottom and falls over. This collapsing wave is called a breaker.

Now we wave goodbye to this part of the lesson, for now.