Chapter 2

Return to Marine Biololgy
Chapter 2 Notes:

The Water Planet
Oceans cover 71%
2/3 of Northern Hemisphere is land
N. Hemisphere is 61% ocean
S. Hemisphere is 80% ocean.
One Interconnected Ocean
The Southern Ocean
What ocean is between Australia and North America?
Pacific Ocean
What ocean is between North America and Africa?
Atlantic Ocean
What ocean is between Africa and Australia?
Indian Ocean
What ocean, besides the Indian Ocean, connects the Atlantic and Pacific Oceans?
Arctic Ocean

Just Right
The Earth orbits the Sum in the narrow zone in which liquid water can exist.
If the Earth were closer what would happen to the water?
If the Earth were farther away what would happen to the water?

Group Work/ Internal Structure of the Earth

external image InsideEarthEqkLines.JPG
The internal structure of the earth reflects the planets' early beginings. The inner most layer is called the core which is composed of mixtures of Iron (also known as alloys). The core is made up of a hard inner layer and a liquid outer layer. It is believed by scientists that the motion of the core contributes to the earth magnetic field.
The mantle is the layer above the liquid layer of the core. Scientists are inconclusive on whether the mantle is liquid or solid.
The crust of the earth is the most recognizable layer of the earth because we see it daily. The crust is a very thin layer made up of plates that are constantly moving. There are two types of the crust that can be found and they consist of oceanic crust and continental crust.
An earthquake may have a epicenter in North America, but the waves from the quake travel through the different layers of the earth and can be found on seismographs at different locations of the planet.

Group Work/ Internal Structure of the Earth

Put your work here.

Internal Structure:
¾ size of the Moon
High Pressure 1,000,000 atmospheres
High Temperature 7,200 degrees F
Liquid outer core
Solid inner core
Inner core spins 10 miles more than liquid outer core
Lower mantle passes seismic waves slower
Lower mantle is hotter and softer.
Upper mantle is harder and cooler
Near the melting point of rock so it flows slowly
Cools by convection
Group Work/ The Crust
The distiction between ocean and the continents is caused by the physical and chemical differences in the rocks and whether the rock is covered by water. Most of the earth is covered by water (the ocean) because the nature of underlying rock. Oceanic Crust makes up most of the seafloor. This consists of minerals called Basalt, it is dark colored. Most of the continental rock is called Granite which has a different kind of chemical composition, and the Basalt is lighter in color. The Oceanic Crust is denser than the Continental Crust, though both are smaller and less dense than the Underlying Mantle.

The Crust
Continental Crust
Sinks into the Mantle
Very thick- 12-30 mi.
Older- up to 3.8 billion Yrs
Above the Moho Discontinuity (Total Annihilation, RTS)
Continental Crust
Light in color
Less dense - 2.7 gm/cm2
Large grains
Sodium, potassium, calcium, aluminum
Can be very old,
theoretically billions of years old
Oceanic Crust
7.The mantle is the area outside of the core. It is extrememly hot- near the melting point of rocks. It is almost solid. Because of this it tends to flow morev slowly than the core. Also, it passes seismic waves slowly too. The deeper you go into the mantle, the hotter and softer it is.
8. The three main layers of the earth are the crusts, the mantle, and the core. The core is mostly made of iron or mixtures that are alloys of iron. It is the hottest layer of the earth and also produces the earth's magnetic field.

9. The differences between continental and oceanic crust are caused by physical and chemical diffrences in the rocks themselves rather than whether or not the rocks happen to be covered in water. Oceanic crust consists of minerals called basalt and continental rocks are generally made up with granite. Oceanic crust is denser than continental crust. Continental crust crust has a density of 2.7g/cm and oceanic crust has a density of 3.0g/cm.
10. A statesmen named Francis Bacon noticed the coasts of the continents, on opposite sides of the atlantic fit together like a puzzle. Alfred Wegner proposed the first detailed hypothesis about continental drift. He stated that all continents where once formed together into one super continent called Pangea. And Alfred Wegener also theorized that the continents began to break up about 180 years ago.
Dark in color
More Dense 3.0 gm/cm2
Small grains
Iron and magnesium
Less than 2 million years old
Floating Continents
Continental Drift
Mountain ranges
Mid-ocean ridges
Ocean trenches
Ridges/ Trenches/ Sediments
Magnetic Anomalies/Bands

While studying the ocean ridges, the magnetic orientation in rocks reversed in a pattern of parallel stripes on each side of the ridge.
Convergent Plate Boundary

Divergent Plate Boundary


Volcanic islands along trenches - Arc Islands

Hawaiian Hot Spots

Old Canadian Rocks

Geological Processes Shaped Ocean Habitats
Plate tectonics shapes continental margins
Passive margins:
Start with a continental rise
Continue with a gentle slope
End with a wide shelf
Geological Processes Shaped Ocean Habitats
Active margins:
Start in a trench with on rise
Continue with a steep slope
End with little or no shelf
Sediments (Two main types)
Lithogenous sediment- comes from the weathering of continental rocks.
Coarse material near continents and fine wind blown clays on the open ocean floors
Biogenous sediments- made of skeletons and shells of marine organisms.
Made of calcium carbonate (Forams) or silica (Diatoms and radiolarians ) in microfossils.
external image Forams.jpg
(Public domain images from the U.S. Geological Survey)
Deep-Ocean Basins
Abyssal plains are those parts of the ocean that begin at the edge of the continental margin and continue into the ocean depths. These plains, which are extremely level, are the flattest places on earth and cover approximately one-half of the deep-ocean floor. The flatness of these plains is the result of the accumulation of a blanket of sediments, up to 2 mils thick
Seamounts and Guyots
Seamounts - submerged (underwater) volcanoes
Guyots were once volcanic islands that were worn flat by erosion and then were submerged
Hydrothermal Vents
Black Smoker Chimneys- Chimney like structures made of sulfides that shoot hot water containing fine, black, grains, near an oceanic ridge.
Climate and Continental Margins
The ocean levels where lower during ice ages.
The ice was as thick as 2 miles
Sea level was about 425 feet lower.
Submarine canyons were formed when the water was lower and then submerged
Deep-sea fans are found below these canyons
Global warming if it occurs will melt more ice and cause the oceans to rise

The typical continental margins contains a shelf, slope, rise, and a plain. The continental shelf is the shallowest area of the continental margin and the sediment is biologically rich. The continental slope is almost the exact location of the edge of the continents. The continental rise consists of a thick layer of sediments and is located below the continental slope. The abyssal plain is the sea floor and is almost completely flat. the shelf, sope, rise, and plain make up to form the ocean floor.
The internal structure of the earth consists of three main layers that are arranged according to their densities.The heavier elements like iron form the solid core. The mantle is slightly solid, but can flow slowly due to its hih temperature. The crust is the third and final layer of the earth and is very thin and emensly solid. Oceanic and continental crust vary greatly in make up and age because continental crust is less dense then oceanic crust so when they collide the oceanic crust sinks into the mantle where it is destroyed in trenches. It is then recreated at underwater volcanoes. Density plays a big role in how the earth is constucted and how events likethe collison of oceanic and continental crust unfold.

Tanya Weiss
Continental margins are the boundaries between the continental crust and the oceanic crust. Sediment deposits on the continental margins can be as thick as 10 km (6 miles). Continental margins consist of: a continental shelf, a continental slope, and a continental rise. The continental shelf is the shallowest part of the continental margin although it only makes up about 8% of the ocean's surface area, it is, biologically, the richest part of the ocean. the continental shelf ends at the shelf break. The continental slope is the closest thing to the exact edge of the continent. The continental rise is made up of a thick layer of sediment piled up on the sea floor. The abyssal plain is almost completely flat to the sea floor. all of these make up the sea floor.

The internal structures of the Earth are made up of different layers that are arranged by their density. These layers are: the inner and outer core, the mantle, and the continental and oceanic crust. The core is made up of the heavier elements such as iron. The mantle is slightly solid, but can flow very slowly due to its high temperature. The crust is the thinest part of the Earth. the oceanic and continental crusts vary greatly not only in make up but also in age. These parts make up the internal structures of the Earth.

The differences between the oceanic and continental crust is their densities, thicknesses, colors, elements, and ages. The continental crust has a density of 2.7 and the oceanic crust has a density of 3. The continental crust is 3 miles thick while the oceanic crust is 21 miles thick. The sea floor is made up of basalt which is a darker color and the continents are made up of granite which is lighter in color. The oceanic crust is the youngest of the two. There are many differences between the continental crust and the oceanic crust.

Plate boundaries are composed of mid-ocean ridges, island arcs, continental valcanoes, high mountains, and faults. Mid-ocean ridges happen when oceanic plates move apart and when they collide it is called island arcs. When oceanic and continental plates collide they form continental valcanoes. High mountains are caused when continental plates collide. Faults are plates that slide past one another. These are many of the different types of boundaries.

Ben Hudgins
The four major oceans on earth are all interconnected to form , the world ocean . The southern ocean around Antarctica touches all the other oceans . The pacific , Atlantic and Indian oceans are all considered branches of the southern ocean .This interconnected system of vast bodies of water allows animals and shipping to travel all around the world .

There are two different types of crust the continental and oceanic crust , the are a many different features unique to each crust such as their chemical composition. Continental plates are generally made up mostly granite while the oceanic plates are composed of a dark colored mineral called basalt. oddly enough oceanic crust is heavier than the continental crust which weighs about 2.7 g/cm3 while the oceanic crust weighs about 3.0 g/cm3 . That doesn't seem like that should be true considering the fact that the continental crust is thicker than the oceanic crust . The oceanic crust is younger than the continental crust about 3.6 billion years younger do to the fact that the oceanic plates are constantly being spread apart by fissures made by magma being pushed to the surface creating more land .

The destruction of ocean crust occurs when two tectonic plates collide with each other pushing until one is pushed int the mantel where the pressure and heat crush it and melt it until there is nothing left . a ridge is formed on the surface when this happens and it sometimes allows magma from the mantle to rise to the surface creating new earth .the material that was pushed up solidifies as it comes in contact with the cool ocean water becoming rock . The magnetic bands in mid ocean ridges run parallel to one another and they represent zones where rocks on the sea floor that have normal and reversed magnetization thats called a magnetic anomaly. Sea floor sediment is basically mud that has settled on the ocean floor and moves away from the crest of mid ocean ridges .subduction zones are were two lithospheric plates collide and one is forced into the mantle where it is destroyed .

The sea floor is divided into 2 main regions : the continental margins which are the submerged edges of the continents , and the deep sea floor itself. The 2 types of margins passive and aggressive . The passive margins typically have flat coastal plains and wide shelves and gradual coastal slopes. Active margins have intense geological activity including earthquakes and volcanoes . Continental margins basically consist of a shelf , a slope , and a rise , further out to lies the abyssal plain . all these very from place to place .

The solid plates that make up the surface of the earth are called lithospheric plates .

Tiffany Steward
The internal structure of the earth is a complex one due to the many layers it has. However, it can be simplified into three main layers. The three main layers of the earth are the crust, the mantle, and the core. When the earth was being formed millions of years ago, the particles arranged together according to their density. The heaviest items floated toward the bottom, or core, of the earth. The core is basically made up of iron, or alloys of iron. It is the hottest point on earth.
Jedi Link
Internal Structure of the Earth
The internal structure of the Earth is something that reminds me of a jaw breaker. It’s composed up of many layers that are arranged according to density. The crust, which is on top, is thin and hard. It varies greaten in the make up and age. Underneath the crust is the mantle. The mantle maybe solid, it can flow slowly due to its high temperature. The core, witch is in the center of the planet, is formed mostly of iron. The outer core is liquid, while the inner core is solid. That makes up earths structure.

Plate boundaries
The earths crust is composed up of many plates. All of these plates are constantly moving. As the plates slide past each other, they from fault lines that goes for miles. Then continental plates collide with each other, you have continental volcanoes. And if two oceanic plates collide, you get island arcs. Also, if two oceanic plates move apart, you get mid-ocean ridges. You have a lot of potential destruction in the movement of the plates.

Typical Continental Margin
Every inch of all continents has an underwater extension of the coast. This extension is call the continental shelf. This area receives the most sunlight, so the point where the shelf starts to plunge steeply toward the ocean floor. Below continental slops, sediment often collect to from gentle slopes called continental rises. Sometimes you get abyssal plains when the ocean floor forms vast extensions that are flat and covered with sediment. This is all that appears at the edge of the continent.

Concept of the World Ocean
The earth’s surface is covered by oceans and several huge land masses. The Ocean covers about 71% of our planet’s surface. Antarctica is the only continent that is completely surrounded by three different oceans. The pacific, Atlantic, and Indian are the oceans that surround it. Its one interconnected system.

Ben Lee
Internal structure of the earth is made by cloud and dust billions of years ago.its layers are arranged according to density the clouds make the layers in the earth.Heavy elements like iron form the core of the earth witch is hot.The mantle is solid but can flow slowly due to its high temprature.Right above the mantle is the crust witch is then and hard.The oceanic and continental crust very in many diffrent ages from several hundred millions to billions.
Plate booundaries help seprate continents.The oceanic plates moving apartt from each other avoid collision.Instead of concept ocean there is a world ocean.Most of the worlds surface is coverd in 71% ocean water.Also antarctica is surronded by ocean to.Mostly the pacific,atlantic,and indian oceansare branches of the ocean surrounding antarctica.That is one interconnected system.
Continental margin that are typical to us.The shelf becomes abruptly steeper.Somtimes shelf's are biologically rich mostly not to some organisms like oysters and muscles.It may lead towards a slope near the ocean going further down.Also it may lead toward the edge of the continents that lead deeper to newer fish.If a volcanic eruption occurs it will rise.Usually they have thick layers of sediments of them for organisms.Under water is mostly full of plains,there are more plains then islands.It is almost a flat sea area.