Oceanography 1

Question 1

Describe the ORIGINS OF LIFE in the oceans.

Answer 1

Earliest life forms were Archaea (4.5 billion years ago)
Started out in ocean vents under anoxic conditions

Question 2

Name the features of a MARINE ENVIRONMENT.

Answer 2

Trench
Mid-oceanic ridge
Abyssal plain (gradients less than 0.05)
Continental slope
Continental shelf
Sea mounts (gradient up to 25 degrees)

Question 3

Name all of TODAY’S OCEANS.

Answer 3

North Pacific
South Pacific
North Atlantic
South Atlantic
Indian
Arctic
Southern

Question 4

Explain why the ELEVATION OF THE SEAFLOOR is greater than that on the land.

Answer 4

The Earth’s crust (lithosphere) is broken into 8 plates which can move (converge/diverge) causing deformations
Oceanic crust is much thinner than continental crust so greater deformations

Question 5

Describe a DIVERGENT PLATE BOUNDARY.

Answer 5

Spreading
Constructive (ocean lithosphere created)
Ridge/ rift
Volcanos
Mid-Atlantic Ridge

Question 6

Describe a TRANSFORM PLATE BOUNDARY.

Answer 6

Lateral sliding
Conservative (ocean lithosphere remains the same)
No major topography
No volcanos

Question 7

Describe a CONVERGENT PLATE BOUNDARY.

Answer 7

Subduction
Destructive (ocean lithosphere destroyed)
Trench
Volcanos
Mariana Trench

Question 8

Define ISOSTASY.

Answer 8

Where gravity and buoyancy act on the Earth’s outer layers and bring them closer together

Question 9

Define BATHYMETRY.

Answer 9

The measurement of ocean depth and charting the shape of the ocean floor (e.g. can use echo sounders)

Question 10

What was the HMS CHALLENGER?

Answer 10

Navy ship turned into a laboratory set sail in 1872
Voyage lasted 4 years and they collected data about depth and topography of the sea floor all over the world
Bathymetric contour map was produced and 4700 new species found