OceansOceansCharacteristicsCharacteristics

FeaturesFeatures

Life FormsLife Forms

The World’s OceansThe World’s Oceans

71% of the Earth’s surface is covered 71% of the Earth’s surface is covered by water.by water.

The oceans contain 97% of the The oceans contain 97% of the earth’s water.earth’s water.

All the oceans and seas are actually All the oceans and seas are actually one continuous body of water.one continuous body of water.

OceanographersOceanographers are scientists who are scientists who study the ocean and its processes.study the ocean and its processes.

Importance of Oceans

• Oceans affect all living things—even those far from the shore.

• Oceans provide a place for many organisms to live.

How were the oceans formed?How were the oceans formed? When Earth was still a young When Earth was still a young

planet, many active volcanoes planet, many active volcanoes existed. As they erupted, lava, existed. As they erupted, lava, ash, and gases were released ash, and gases were released from deep within the Earth.from deep within the Earth.

One of these One of these

gases was gases was

water vapor.water vapor.

Formation of OceansFormation of Oceans

• Over millions of years, the Over millions of years, the waterwater vaporvapor cooled enough to condense cooled enough to condense and form clouds. Then torrential and form clouds. Then torrential rains began to fall from the clouds. rains began to fall from the clouds.

Eventually, much Eventually, much

of the land was of the land was

covered by covered by

water that formedwater that formed

OceansOceans The oceans are the Atlantic, The oceans are the Atlantic,

Pacific, Indian, and Arctic.Pacific, Indian, and Arctic. The Pacific Ocean is the The Pacific Ocean is the

largest ocean.largest ocean. The area and volume of the The area and volume of the

Pacific Ocean are greater than Pacific Ocean are greater than the Atlantic and Indian the Atlantic and Indian combined.combined.

SeasSeas A A seasea is one of the largest is one of the largest

bodies of salt water, less bodies of salt water, less than an ocean, found on than an ocean, found on the earth’s surface.the earth’s surface.

The Mediterranean, Arctic The Mediterranean, Arctic and Black Sea are really and Black Sea are really part of the Atlantic Ocean.part of the Atlantic Ocean.

Properties of Ocean WaterProperties of Ocean Water Ocean water is a mixture of Ocean water is a mixture of

gases and solids dissolved in gases and solids dissolved in pure water.pure water.

Oceanographers believeOceanographers believe oceans contain all the natural oceans contain all the natural elements on Earth.elements on Earth.

85 of 90 have been found in 85 of 90 have been found in the oceanthe ocean..

Major Elements in the OceanMajor Elements in the Ocean Ocean water is 96% pure Ocean water is 96% pure

water.water. ChlorineChlorine (1.9) and (1.9) and sodiumsodium

(1.1) make up the next (1.1) make up the next largest concentration of largest concentration of elements.elements.

Sodium chloride is table salt.Sodium chloride is table salt.

SalinitySalinity

SalinitySalinity describes the describes the amount of amount of dissolved salt in dissolved salt in the ocean.the ocean.

Salinity is Salinity is expressed in expressed in parts per parts per thousand.thousand.

Gases in Ocean WaterGases in Ocean Water The most abundant gases in The most abundant gases in

ocean water areocean water are nitrogen, carbon nitrogen, carbon dioxide and oxygen.dioxide and oxygen.

The amounts of these elements The amounts of these elements vary with depth. They are more vary with depth. They are more abundant at the ocean’s surface abundant at the ocean’s surface where sunlight causes more plant where sunlight causes more plant life.life.

Temperature of Ocean WaterTemperature of Ocean Water Warm water holds less dissolved Warm water holds less dissolved

gas than cold water.gas than cold water. When ocean water is cold, like in When ocean water is cold, like in

polar regions, it sinks and carries polar regions, it sinks and carries oxygen rich water to the ocean oxygen rich water to the ocean depths.depths.

As a result, fish and other As a result, fish and other animals can live in deep partsanimals can live in deep parts of of the ocean.the ocean.

Waves

• A wave in water is a rhythmic movement that carries energy through the water.

• Waves are caused by high winds blowing on top of the water.

Tides• Throughout a day, the water level

at the ocean’s edge changes. This rise and fall in sea level is called a tide.

• A tide is a giant wave that can be thousands of kilometers long but only 1 m to 2 m high in the open ocean.

• Tides are created by the gravitational attraction of Earth and the Moon and of Earth and the Sun.

TidesTides Refer to page Refer to page

H125.H125.

TidesTides• Tides are created by the gravitational attraction of Earth and the Moon and of Earth and the Sun.

Movement of WaterMovement of Water UpwellingUpwelling is the upward is the upward

movement of cold water movement of cold water from the ocean depths.from the ocean depths.

UpwellingUpwellingUpwellingUpwelling brings brings

up tiny ocean up tiny ocean organisms, organisms,

minerals, and minerals, and other nutrients other nutrients

from the deeper from the deeper layers of the layers of the

water; without water; without upwelling the upwelling the surface of the surface of the

ocean would be ocean would be nutrient deficientnutrient deficient..

El NinoEl Nino

El NinoEl Nino is an abnormal is an abnormal climate event that occurs climate event that occurs every 2-7 years in the every 2-7 years in the Pacific Ocean, causing Pacific Ocean, causing changes in the winds, changes in the winds, currents, and weather currents, and weather patterns.patterns.

El NinoEl Nino El Nino interrupts up the

pattern of upwelling. Without nutrients provided by

upwelling, fish and other organisms cannot find food.

Fish and other organisms die and weather patterns are disturbed.

The Ocean FloorThe Ocean Floor The ocean floor has higher mountains, The ocean floor has higher mountains,

deeper canyons, and larger flatter deeper canyons, and larger flatter plains. plains.

Earthquakes occur more often.Earthquakes occur more often. The rocks are very different.The rocks are very different. The crust is thinner.The crust is thinner.

Continental ShelfContinental Shelf The The continental shelfcontinental shelf is the is the

gradually sloping end of a gradually sloping end of a continent that extends under the continent that extends under the ocean.ocean.

The ocean covering the The ocean covering the continental shelf can be as deep continental shelf can be as deep as 350 m.as 350 m.

Large mineral, oil and natural gas Large mineral, oil and natural gas deposits are found here.deposits are found here.

Continental SlopeContinental Slope At the edge of the continental At the edge of the continental

shelf, the ocean floor plunges shelf, the ocean floor plunges steeply 4 to 5 kilometers.steeply 4 to 5 kilometers.

The The continental slopecontinental slope extends from the outer edge extends from the outer edge of the continental shelf down of the continental shelf down to the ocean floor.to the ocean floor.

Abyssal PlainsAbyssal Plains Large, flat areas on the ocean Large, flat areas on the ocean

floor are called floor are called abyssal plains.abyssal plains. The abyssal plains are larger in The abyssal plains are larger in

the Atlantic and Indian than in the the Atlantic and Indian than in the Pacific due to the deposition of Pacific due to the deposition of sediments by large rivers.sediments by large rivers.

The Pacific Ocean has large cracks The Pacific Ocean has large cracks that trap sediments and result in that trap sediments and result in smaller abyssal plains.smaller abyssal plains.

Abyssal PlainsAbyssal Plains Abyssal plainsAbyssal plains are close to the are close to the

continent and are made of mud, continent and are made of mud, sand and silt.sand and silt.

Farther out on the abyssal plains, Farther out on the abyssal plains, some of them contain the remains some of them contain the remains of tiny organisms that form ooze.of tiny organisms that form ooze.

Where ocean life is not abundant, Where ocean life is not abundant, the floor of the ocean is covered the floor of the ocean is covered with red clay.with red clay.

Seamounts and GuyotsSeamounts and Guyots SeamountsSeamounts are underwater volcanic are underwater volcanic

mountains that rise more than 100 mountains that rise more than 100 meters above the ocean floor. Most meters above the ocean floor. Most have been found in the Pacific Ocean.have been found in the Pacific Ocean.

Some seamounts reach above the Some seamounts reach above the surface of the water to form islands, surface of the water to form islands, like the Azores in the Atlantic and the like the Azores in the Atlantic and the Hawaiian islands in the Pacific.Hawaiian islands in the Pacific.

GuyotsGuyots are flat-topped seamounts. are flat-topped seamounts.

TrenchesTrenches TrenchesTrenches are the are the

deepest parts of deepest parts of the ocean found the ocean found along the edge of along the edge of the ocean floor.the ocean floor.

The Mariana Trench The Mariana Trench in the Pacific Ocean in the Pacific Ocean contains the contains the deepest spot (1100 deepest spot (1100 meters) on Earth meters) on Earth known as known as Challenger Deep.Challenger Deep.

Mid-ocean RidgesMid-ocean Ridges• A mid-ocean ridge is the area in an ocean

basin where new ocean floor is formed. The mid-ocean ridges form an almost The mid-ocean ridges form an almost

continuous mountain belt that extends continuous mountain belt that extends from the Arctic Ocean down through the from the Arctic Ocean down through the middle of the Atlantic Ocean around Africa middle of the Atlantic Ocean around Africa into the Indian Ocean and across the Pacific into the Indian Ocean and across the Pacific Ocean.Ocean.

In the Atlantic it is called the mid-Atlantic In the Atlantic it is called the mid-Atlantic Ridge and in the Pacific, the Pacific-Ridge and in the Pacific, the Pacific-Antarctica Ridge.Antarctica Ridge.

Ocean Life ZonesOcean Life Zones The plant and animal life in the The plant and animal life in the

ocean is affected by several ocean is affected by several factors.factors.

One factor is the amount of One factor is the amount of sunlight that penetrates the sunlight that penetrates the ocean.ocean.

Another factor is the Another factor is the temperature of the ocean water.temperature of the ocean water.

Water pressure is also a factor.Water pressure is also a factor.

Major Groups of Ocean LifeMajor Groups of Ocean Life Plants and animals in the Plants and animals in the

ocean are classified into ocean are classified into three major groups based on three major groups based on their habits and the depth of their habits and the depth of the water in which they live.the water in which they live.

The three major groups are The three major groups are planktonplankton, , nektonnekton and and benthosbenthos..

PlanktonPlankton PlanktonPlankton float at or near the surface float at or near the surface

where sunlight can penetrate.where sunlight can penetrate. Most of the plankton are very small, Most of the plankton are very small,

such as algae.such as algae. These organisms drift with the These organisms drift with the

currents or tidescurrents or tides.. Plankton are the main food for Plankton are the main food for

many larger organisms. They many larger organisms. They account for most of the organisms account for most of the organisms in the ocean.in the ocean.

PlanktonPlankton Jellyfish, which float on the Jellyfish, which float on the

ocean surface, is one ocean surface, is one example ofexample of plankton.plankton.

NektonNekton Whales, seals, dolphins, squid Whales, seals, dolphins, squid

octopuses, barracuda and other fish octopuses, barracuda and other fish are all nektonare all nekton..

NektonNekton are free-swimming organisms are free-swimming organisms that feed on other nekton as well as that feed on other nekton as well as on plankton.on plankton.

Many have adaptations enabling them Many have adaptations enabling them to function at depths that have great to function at depths that have great pressure and no light.pressure and no light.

NektonNekton This beautifully colored fish is This beautifully colored fish is

classified as classified as nekton.nekton.

BenthosBenthos

Organisms that live on the ocean floor Organisms that live on the ocean floor are are benthos.benthos.

Crabs, and lobster are just a few Crabs, and lobster are just a few examples of benthos.examples of benthos.

The deep bottom environments are The deep bottom environments are sparsely populated with benthos.sparsely populated with benthos.

Some benthos are plants that live on Some benthos are plants that live on the ocean floor in shallow waters the ocean floor in shallow waters where sun can penetrate.where sun can penetrate.

BenthosBenthos A starfish is an example of benthosA starfish is an example of benthos..