Option B: Oceans and Coastal Margins Flashcards
Ocean Current
A seasonal directed movement of seawater generated by forces acting upon this mean flow, such as breaking waves, wind, the Coriolis Effect, temperature and salinity differences.
Tide
Caused by the gravitational pull of the sun and moon.
Surface ocean currents caused by the influence of _____ winds blowing steadily across the seas surface.
Prevailing
Gyre
A large system of rotating, usually circular ocean currents.
How many “main” gyres are there in the world?
Five
What direction (clockwise / anti-clockwise) do gyres in the Northern hemisphere flow compared to in the Southern hemisphere?
Clockwise in Northern Hemisphere
Anti-clockwise in Southern Hemisphere
What and in what direction does the Gulf stream transport?
Transports heat northwards and then eastwards across the North Atlantic (USA –> UK)
In the redistribution of heat, where does warm vs. cold water flow in terms of the equator?
Warm water travels away from the equator to the colder regions.
Colder water travels to the equator to heat up.
Why are ocean currents so important? (3 reasons)
- Bring nutrients to the surface
- Transfers heat (redistribution)
- Responsible for mass migration of marine species
Upwelling Currents
Bring nutrients for fish, birds and people at the surface from the ocean floor (where most nutritious organic matter is located).
Downwelling Currents
Salty and cold but brings oxygen to species at ocean floor. Otherwise the ocean floor would become toxic due to all the biproducts of decomposition.
Specific Heat Capacity
The amount of energy it takes to raise the temperature of a body.
The global ocean conveyor belt is…..
a constantly moving system of deep-ocean circulation driven by temperature and salinity.
Thermohaline Circulation
The idea that global conveyor belt is driven by temperature and salinity changes.
Dune
A mound of sand formed by the wind along a beach.
Dunes form when….
Wind blows sand into a sheltered area behind an obstacle. Dunes grow as grains of sand accumulates.
What is the process called of sand moving up the beach and describe it.
Saltation.
“Hopping” of sand particles up the beach.
(Suspension) = carried by wind
Saltation = rolling / hopping
(Dunes) Vegetation is required for ____
A dune to become stable. In fully developed dune systems, the process of succession takes place where the range and density of vegetation changes from youngest to oldest dunes.
Name an example of a sand dune vegetation and the adaptations it has had to overcome.
Marram grass / sea couch:
Adapted to salty, dry, windy and nutrient poor conditions,
What is needed for dunes to form? (4 things)
- Wind (for saltation to occur and transport sand upwards).
- Sand (dunes don’t form with pebbles)(preferably dry sand as wet sand cannot be transported by the wind.
- Wide beach (saltation needs time and space.
- Flat surface (dunes can’t form on a slope).
