Oceanography. I. Introduction to Oceans A. Oceanography – the study and exploration of the world’s oceans. A. Oceanography – the study and exploration

OceanographyOceanography

I. Introduction to Oceans I. Introduction to Oceans

A. Oceanography – the study and A. Oceanography – the study and exploration of the world’s exploration of the world’s oceans.oceans.

B. Formation of the ocean waters B. Formation of the ocean waters – water vapor and condensation– water vapor and condensation

of vapor as rain in the of vapor as rain in the ocean basinsocean basins

II. Properties of Ocean WaterII. Properties of Ocean Water

A.A. Composition of Ocean Water Composition of Ocean Water

1. H1. H22O is 96.5 %O is 96.5 %

2. other elements is 3.5%2. other elements is 3.5%

3. 3. salinitysalinity – dissolved salt – dissolved salt content of a body of watercontent of a body of water


B. Temperature of Ocean WaterB. Temperature of Ocean Water 1. as temperature increases, density 1. as temperature increases, density

decreasesdecreases 2. 2. surface temperature surface temperature – from 2– from 2OOC C

(Arctic) to 28(Arctic) to 28OOC (equator)C (equator) 3. 3. subsurface temperature subsurface temperature – from – from

11OOC to 3C to 3OOCC 4. 4. thermocline thermocline – – zone where there is a zone where there is a

sharp difference in temperature between sharp difference in temperature between surface and deeper water.surface and deeper water.


C. C. Pressure Pressure – pressure increases – pressure increases as the ocean depths increasesas the ocean depths increases

D. D. ColorColor – natural color is blue, – natural color is blue, but can be affected by but can be affected by pollutants or microscopic plantspollutants or microscopic plants

III. Oceans – a continuous body of saltwater that III. Oceans – a continuous body of saltwater that covers approximately 70% of the Earthcovers approximately 70% of the Earth

A. A. PACIFIC PACIFIC – the largest, deepest, covers 1/3 – the largest, deepest, covers 1/3 of the Earth’s surface, contains of the Earth’s surface, contains approximately ½ of the Earth’s water.approximately ½ of the Earth’s water.

B. B. ATLANTIC ATLANTIC – second largest, contains – second largest, contains Mediterranean, Caribbean and North Mediterranean, Caribbean and North Seas, shallower than Pacific and IndianSeas, shallower than Pacific and Indian

III. Oceans

C. C. INDIANINDIAN - deeper than the Atlantic, - deeper than the Atlantic, shallower than the Pacificshallower than the Pacific

D. D. ARCTICARCTIC – surrounds the geographic – surrounds the geographic North Pole North Pole

IV. Life in the OceanIV. Life in the Ocean

A. Plankton – drifting organisms in A. Plankton – drifting organisms in aquatic environments (marine aquatic environments (marine and freshwater). The base of the and freshwater). The base of the food web in these environmentsfood web in these environments

1. phytoplankton – plant 1. phytoplankton – plant plankton – example – diatomsplankton – example – diatoms

2. zooplankton – animal-like 2. zooplankton – animal-like plankton example- protists, plankton example- protists, crustaceanscrustaceans


B. Nekton – organisms that swim B. Nekton – organisms that swim in the ocean freely.in the ocean freely.

examples – larger fish, squid, examples – larger fish, squid, sea turtles, whalessea turtles, whales


C. Benthos – community of organisms that C. Benthos – community of organisms that live on, in, or near the ocean floor live on, in, or near the ocean floor

examples – crabs, coral, starfish, clams, examples – crabs, coral, starfish, clams, sea anemonessea anemones

1. benthic environment – region near or 1. benthic environment – region near or at the bottom of a pond, lake, or ocean, at the bottom of a pond, lake, or ocean, including organisms that live thereincluding organisms that live there

2. pelagic environment – ecological realm 2. pelagic environment – ecological realm that includes the entire ocean water that includes the entire ocean water columncolumn

Threats to the Ocean

The oceans are huge but are becoming increasingly more polluted.

Overfishing is also destroying fish populations.

V. Marine Ecosystems

Includes: estuaries, coral reefs, oceans, and polar ecosystems

Marine ecosystems contain dissolved _____.

In oceans, lack of water is not a problem. Therefore, the types of organisms present are dependent upon __________, sunlight available, and ___________.

salt

temperaturenutrients

Estuaries

Estuaries

An ecosystem where _____ _____ from rivers and streams mixes with _____ _____ from the ocean.

Estuaries contain plenty of light and nutrients which support large populations of plants and animals.

Plants and animals that live in estuaries are able to tolerate variations in ________ because the _____ content of the water varies as the fresh and salt water mix.

fresh water

watersalt

salinitysalt

Threats to Estuaries

Estuaries provide harbors, access to the ocean, and connections to rivers. As a result, many of the world’s largest cities are built on estuaries.

Because of this, many estuaries have become polluted.

Coral Reefs

Coral Reef

Coral reefs are __________ islands in the sea that are built by coral animals called polyps.

Thousands of species of plants and animals live in the cracks and crevices of coral reefs, making coral reefs among the most ________ ecosystems on Earth.

Corals can only live in _____ salt water where there is enough ______ for photosynthesis. Therefore, coral reefs are only found in shallow, tropical seas.

limestone

diverse

warmlight

Threats to Coral Reefs

If the water surrounding a reef is too hot or cold, or if fresh water drains into the water surrounding a reef, corals have trouble producing limestone.

If the water is too muddy, too polluted, or too high in nutrients, algae that live within the corals will die or grow out of control and smother the corals.

Oil spills, sewage, pesticide, and silt runoff have all been linked to coral reef destruction.

Polar Ecosystem

Polar Ecosystems

The ice-covered polar caps can be considered marine ecosystems because nearly all food is provided by phytoplankton in the ocean.

The ______ Pole is in the Arctic Ocean and the ______ Pole is in Antarctica.

________ provides the main source of food at both poles.

NorthSouth

Plankton

Threats to Polar Ecosystems

Oil extraction, tourism, and garbage are the worst threats to the polar ecosystems.

Conservationists want these areas to become world wildlife refuges.

Upwelling refers to deep water that is brought to the surface.

Areas of upwelling are created by surface winds that pull water away from an area. This deficit of water on the surface invites water to come up from deeper regions.

To understand upwelling, you must be familiar with how the Coriolis Effect affects ocean surface currents. The Coriolis Effect acts on moving water, because it is not attached to the rotating Earth. As water flows over the rotating earth, it appears to deflect to the right in the Northern Hemisphere and the left in the Southern.

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm

The deep water that surfaces in upwelling is cold; by looking at Sea Surface Temperature maps we can identify cool upwelled water versus hotter surface water.

Upwelled water also contains nutrients (nitrate, phosphate, silicate) and dissolved gases (oxygen and carbon dioxide) that are not utilized at depth because of a lack of sunlight.

Now on the surface, these nutrients and gases help to fuel photosynthesis by small algae called phytoplankton.

Phytoplankton photosynthesize using specialized color pigments called chlorophyll. Thus, “Ocean Color” maps are another way to identify areas of upwelling. Where on this ocean color map are high phytoplankton concentrations?

Ecological and Economic effects of upwelling:

Upwelling leads to more phytoplankton

More phytoplankton leads to more fish

More fish lead to commercial fishing jobs and to more seafood

Even though upwelling areas account for only 1% of the ocean surface, they support 50% of the worlds fisheries.

Phytoplankton come in many shapes and forms. Collectively they form the base of

oceanic food webs.

Without upwelling many of the Without upwelling many of the world’s fisheries would not thrive.world’s fisheries would not thrive.

Some climatic events can reduce upwellings.

El Nino

~

Along Peru’s coast, an El Nino event decreases the coastal winds. Thus the upwelling from below is slowed.

An El Nino condition results from weakened trade winds in the western Pacific

Ocean near Indonesia, allowing piled-up warm water to flow toward South America.

What is La Niña?

La Niña is characterized by unusually cold ocean temperatures in the Equatorial Pacific, compared to El Niño, which is characterized by unusually warm ocean temperatures in the Equatorial Pacific.

VI. Instruments of InvestigationVI. Instruments of Investigation

A.A. SCUBA SCUBA – Self-Contained Underwater – Self-Contained Underwater Breathing Apparatus. Tanks of Breathing Apparatus. Tanks of compressed air strapped on a diver’s compressed air strapped on a diver’s back and connected by hoses to a back and connected by hoses to a mouthpiece for breathingmouthpiece for breathing

B.B. SONAR SONAR – Sound Navigation And Radar. – Sound Navigation And Radar. Methods of mapping the ocean floor by Methods of mapping the ocean floor by transmission and reflection of sound transmission and reflection of sound waveswaves

Instruments of Investigation (cont.)Instruments of Investigation (cont.)

C. C. Geostationary operational Geostationary operational Environmental Satellites (GOES)Environmental Satellites (GOES) orbit the Earth at 22,000 miles. orbit the Earth at 22,000 miles. They are highly advanced They are highly advanced observation platforms supplying observation platforms supplying detailed imagery of the Earth’s detailed imagery of the Earth’s oceansoceans


D. D. Underwater Laboratories Underwater Laboratories – The – The Aquarius Aquarius Underwater Laboratory is Underwater Laboratory is the only undersea laboratory the only undersea laboratory dedicated to marine science dedicated to marine science operating in the world. operating in the world. AquariusAquarius provides life support systems that provides life support systems that allow scientists to live and work allow scientists to live and work underwater, in reasonably underwater, in reasonably comfortable living quarters, with comfortable living quarters, with sophisticated research capabilitiessophisticated research capabilities


E. Deep ocean submersibles – Over the last E. Deep ocean submersibles – Over the last few decades, engineers have developed few decades, engineers have developed technologies capable of meeting the technologies capable of meeting the many challenges that the deep sea many challenges that the deep sea imposes upon explorers. imposes upon explorers.

VIII. Waves and Wave ActionVIII. Waves and Wave Action

A. A. Causes – wind and earthquakesCauses – wind and earthquakes

B. Characteristics of WavesB. Characteristics of Waves

1. crest – highest point of a wave1. crest – highest point of a wave

2. trough – lowest point of a wave2. trough – lowest point of a wave

3. wavelength – distance between3. wavelength – distance between

2 adjacent wave crests or wave2 adjacent wave crests or wave

troughstroughs


4. wave frequency – the number of 4. wave frequency – the number of

waves that pass a point in a waves that pass a point in a

certain amount of timecertain amount of time

5. wave period – time between the5. wave period – time between the

passage of two wave crests (orpassage of two wave crests (or

troughs) at a fixed pointtroughs) at a fixed point


6. wave height – vertical distance 6. wave height – vertical distance between crest and trough of a between crest and trough of a wavewave 7. breaker – high wave crest that 7. breaker – high wave crest that has been pulled down by gravityhas been pulled down by gravity 8. surf – area between the breaker 8. surf – area between the breaker zone and the shorezone and the shore

9. white caps – wave crests breaking9. white caps – wave crests breaking

into white foaminto white foam


10. swells – formation of long wavelength 10. swells – formation of long wavelength surface waves more stable than normal surface waves more stable than normal wind waves and formed by stormswind waves and formed by storms

11. deep water waves – waves that move 11. deep water waves – waves that move in water deeper than ½ their wavelengthin water deeper than ½ their wavelength

12. shallow water waves – waves that 12. shallow water waves – waves that reach water shallower than ½ their wave reach water shallower than ½ their wave heightheight


C. Tsunami – a great sea wave caused C. Tsunami – a great sea wave caused especially by undersea earth movement especially by undersea earth movement or volcanic eruptionor volcanic eruption


D. storm surge – an offshore rise of water D. storm surge – an offshore rise of water often associated with a low pressure often associated with a low pressure weather system, typically tropical weather system, typically tropical cyclonescyclones

E. undertow – the current beneath the E. undertow – the current beneath the surface that sets seaward or along the surface that sets seaward or along the beach when waves are breaking on the beach when waves are breaking on the shoreshore

F. longshore current – an ocean current that F. longshore current – an ocean current that move parallel to the shoremove parallel to the shore

IX. Tides IX. Tides

A. Tidal range – the vertical difference A. Tidal range – the vertical difference between high and low tidesbetween high and low tides

1. high tides – occur twice a day, when 1. high tides – occur twice a day, when the ocean water bulges as a result of the ocean water bulges as a result of the gravitational pull of the overhead the gravitational pull of the overhead moonmoon

2. low tides – occur twice a day, when 2. low tides – occur twice a day, when the two areas of the earth are not the two areas of the earth are not experiencing high tideexperiencing high tide

IX. Tides IX. Tides

B. Spring Tide – exceptionally high B. Spring Tide – exceptionally high and low tides that occur at the time and low tides that occur at the time of the full and new moons, when of the full and new moons, when the sun, earth, and moon are the sun, earth, and moon are approximately aligned approximately aligned

C. Neap Tide – times when the C. Neap Tide – times when the difference between high and low difference between high and low tide are minimized. Occur during tide are minimized. Occur during quarter moonsquarter moons

X. Currents and ClimatesX. Currents and Climates

A. Surface currents – Horizontal movement of A. Surface currents – Horizontal movement of seawater in the oceanseawater in the ocean

1. are driven by winds and can affect 1. are driven by winds and can affect movement to a depth of several hundred movement to a depth of several hundred metersmeters

2. either cool or warm the air above it 2. either cool or warm the air above it influencing the climate of the land near the influencing the climate of the land near the coast (example – Gulf Stream)coast (example – Gulf Stream)

B. Ocean CurrentsB. Ocean CurrentsDeep Currents Deep Currents

At the shoreline

Water becomes shallow, wave height increases because wave length decreases

Waves become steeper, then collapse (breakers)

Wave refraction

Close to coast, water gets more shallow

Waves are slowed down

If waves arrive at an angle, one part is slower than the rest

Causes waves to bend = wave refraction

Waves arriving at bays are slow (deposition)

At headlands, faster (erosion)

A sequence of features is produced as headlands are degraded

Sea cliffs Waves erode

base -undercutting

• Headlands may be eroded back leaving a remnant (stack)

Longshore drift

Waves arrive at a coast at an angle (swash)

Backwash returns at 90 degrees

Sand is moved along the beach = longshore drift or longshore current

Coastal deposition

Result of longshore drift and a lot of sediment

= produces extensions of deposit from the shoreline

May grow across a bay (baymouth bar)

May link an island to the main land (tombolo)

spit = curved extension

Types of Coastline

Submergence and emergence changes coastlines

Pocket beaches

Emergent coast Uplifted land surface Coastal landforms are found above

present sea level

a wave-cut platform when elevated -

uplifted marine terrace

Barrier Island Coasts

Occur on low lying coasts with gentle gradients

BARRIER ISLANDS - low ridges of sand built by waves behind the islands are

lagoons shallow water with tidal

deposits TIDAL INLETS - gaps between

the islands

Oceanography – Think about it!You will be given a scenario which you

will read. You will then:1. Draw a ‘before’ picture with color

what your area might look like.2. Draw an ‘after’ picture with color

what your area might look like.3. Answer the seven questions on a

separate sheet of paper.DO NOT WRITE ON

‘OCEANOGRAPHY – THINK ABOUT IT!’ PAPER

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Oceanography. I. Introduction to Oceans A. Oceanography – the study and exploration of the world’s oceans. A. Oceanography – the study and exploration