Week 7 Ice, Oceans, Atmosphere (10/8-10/10) Flashcards
why are corals white?
expel symbiotic algae called zooxanthellae
What are corals?
animals
Describe the symbiotic relationship between coral and zooxanthellae.
- Corals provide a home, CO2, and nutrients to the algae
- Algae feed the corals with their dead bodies
Why do coral expel zooxanthellae?
they get stressed out when the water is too warm to avoid excessive accumulation of damaged algal cells
How do we characterize waves?
wavelength and amplitude
How do we calculate wave velocity for deep water?
wavelength (length)*frequency (per time)
*dependent on wavelength
What affects wave height?
farther waves travel when pushed by wind the bigger they get
*fetch
What is fetch?
- How far waves have to build
How do waves move?
- circular orbit
What happens to wave in shallow water?
- slows down
- amplitude increases 1/7 too tall compared to the wavelength causing it to break (to conserve energy)
- circular orbit hits the bottom causing friction
- wavelength shortens
Why is it 1/7?
- density of water
- gravitational strength
- water viscosity
What controls tides?
gravitational pull of other things
What does gravity do?
it only attracts
What are spring tides?
When the sun, moon, and earth are aligned in a straight line
What are neep tides?
When the moon and sun form a right angle with the earth
When is high tide during a full moon?
18:00 10/10
What is a barrier island?
-protects mainland from storms, surges, and waves that would otherwise inundated ecosystems
How does a barrier island protect?
big waves from a storm wash over island and settle on the bay side taking sediment from one side to the other (over wash process)
How are barrier islands maintained?
- sediment supple
- wind energy
- waves that push sediment up and down
- currents, longshore drift (sediments move along island)
How is sea level rise affecting barrier islands?
25:45
How does longshore drift occur?
- when waves come in at an angle and leave in a straight line
- swash & backwash
- when it reaches the end of the island it deposits sediment creating a curved tip
What are groins?
- prevent longshore drift
- sand builds (accretion) on one side (updrift) and gets eroded on the other (downdrift)
- form triangle beaches
What do sea walls do?
- destroy beaches by reflecting wave energy
