Ch4 Flashcards
What is a Thermocline
A body of water with rapid changes in temperature with depth.
Traits of Permanent Thermocline
Occurs in tropical regions
Results in a stable water column with little mixing between warmer surface water and colder deeper water, keeping the surface water warmer.
What are 2 kinds of Thermoclines?
Permanent and Seasonal
Does a Permanent Thermocline occur in the polar regions?
Either has reduced or no permanent thermocline because the surface water does not get warm enough to warm the water further down
Traits of a Seasonal thermocline
Changes between seasons, it disappears during winter then forms again during spring.
Traits of a Seasonal thermocline II
Occurs in temperate and polar regions
The depth of the thermocline is shallow here (20-100 meters)
Why is there NO seasonal thermocline in the tropics
No seasons in the tropics
What is Barotrauma?
Damage to the body due to pressure changes
What is the Coriolis Effect?
The deflection of air and ocean currents due to the rotation of the earth
What direction does the Northern Hemisphere water go?
Right
What direction does the Southern Hemisphere water go?
Left
What effect does the Coriolis effect have on surface currents?
Causes currents to not flow parallel in the direction in which the wind pushes them
What is upwelling
The movement of nutrient rich deep cold water being sent to the surface
Two types of Upwelling
Coastal and equatorial
What does upwelling do to fisheries?
Higher levels of fish in the waters due to increased levels of phytoplankton (Fish food)
What is El Nino?
Changes in temperature distribution in the Pacific, this causes water temperature and atmosphere pressure to switch from the Western and Eastern Pacific
What is the difference between High and Low Pressure
High= Dry weather (California)
Low= Humid/Rainy weather (Philippines)
What causes El Nino?
The Trade Winds decreasing in strength
What are the effects of El Nino?
Coastal Upwelling decreases and permanent thermoclines goes deeper.
Why is El Nino called El Nino?
Because the phenomena was first noticed was around Christmas time, so it was associated with the birth of Christ
What is La Nina?
Occurs when the Trade Winds start up again with unusually stronger winds, creating higher high pressures and lower low pressures.
What is La Nada
When everything is normal in the pacific
What is Downwelling
Cold water with high density sinks down, (Conveyor belt theory)
What happens to the quality of light as you depth increases?
Red light disappears the deeper you go, blue and green travel furthest down
At Sea level, what is the atmospheric pressure
1 Atmosphere of pressure (14.7psi)
What is refraction?
The way light bends as the air moves to water
What are the 3 regions of earth
Polar region (>60 degrees North and South)
Temperate (30-60 degrees North and South)
Tropical (0-30 degrees North and South)
How many meters does it take to add another Atmosphere of pressure when diving?
10 meters (33 feet)
How does Coastal Upwelling occur?
It occurs because the wind is pushing the water either North or South along the coast, so this pushed water is replaced by the water below
How does Equatorial Upwelling occur?
It occurs because the wind pushes the water and it diverges going North or South, so the pushed water is replaced by the water below
What factors affect how light penetrates the ocean?
-Amount of suspended particles
-Clouds
-The angle in which lights hits the water
What zone is photosynthesis usually restricted to?
Photic zone
How are fishes with a swim bladder affected by the change in pressure?
The bladder will either expand or contract
Thermocline super simplified
(Remember this)
> Sunlights heats surface making the top layer less dense
Deeper water stays cool because the sun doesn’t reach
Density prevents mixing, so the warm water (less dense) stays above the colder water (more dense)
Is a Thermocline a stable water column
Yes
Are Stratified and Stable water column the same thing?
Yes
What is a stable water column?
Lighter water staying on top of denser water by preventing mixing
