IB Geography - Option B: Oceans

Currents

Cohesive streams of seawater that circulate through the oceans

Gulf Stream

Permanent current

Eddy Currents

Temporary currents that die out after a few months

Causes of currents

wind, gravity, density

Gyre

Well organized, circular flow, that are found in many different sizes. It is made up of currents that are set up by wind and gravity, but steered by the location of continents.

5 Largest Gyres

2 Atlantic Ocean
2 Pacific Ocean
1 Indian Ocean

Ocean Basin (topography)

Shape of the ocean basins constrain movement of currents. When a current runs into a continent, it turns aside.

Coriolis Effect

Occurs because the Earth's surface rotates faster at the equator than the poles. (To the right in Northern Hemisphere and to the left in the Southern hemisphere)

Labrador current

Flushing ice bergs into the North Atlantic shipping ways

Longshore currents

Flow along coastlines when waves run into the shore at an angle.
-Causes beaches to disappear and harbors to fill in

Rip currents

Where obstacles channel water away from the shore line.
-Causes sweeping away of people from the shore

Upwelling currents

Winds push surface water away from the shore and deeper water rises to fill the gap.
-Causes nutrients to be brought up to the surface and stimulates high animal and plant productivity

Antarctic Circumpolar Current

Ocean current that flows clockwise from west to east around Antarctica

Continental crust

thick, rock granite, not dense

Oceanic crust

thinner, more dense, made of rock with salt

Lithospehere

Outer shell of the Earth and is broken into plates (lithospheric or tectonic) which is the solid outer part of the Earth that we live on

Asthenosphere

Beneath the lithosphere and the plates float on this partially melted layer.

How do the Earth's plates move?

Convection currents in the asthenosphere drive plate motion
-Hot material becomes less dense and rises, then it comes down as it cools off and it sinks

Guyot

A flat-tropped seamount

Mid-Ocean Ridge

Diverging plate boundaries that cause upelling magma to rise and elevate the sea floor into ridges

Salinity

Containing salt

Temperature

Heat

Thermohaline Circulation

Flow of ocean water caused by changes in density

Thermocline

Area of rapid temperature change

Halocline

Area of rapid salinity change

El Nino

Sustained sea surface temperature anomaly across the central tropical pacific. It has global repercussions. The phenomenon that triggers the Equatorial Counter Current.

La Nina

The inverse effect of El Nino

Baseline

Line where seaward limits and terretories are measured from

Internal waters

Waters on landward side of baselin, examples: rivers and lakes

Territorial sea

Coastal state claim a territorial sea that extends to 12 nautical miles. State has sovereignty over sea, airspace and seabed

Contiguous Zone

Band that extends 24 nautical miles where state have control for punishing fringement of its customs, fiscal, immigration or sanitary laws

Exclusive Economic Zone

200 Nautical miles, where a country has economic rights to the sea's abiotic and biotic resources

Continental Shelf

Seabed and subsoil areas that extended beyond the contintent of the state

Nautical miles

A nautical mile is miles adjusted for the circumferance of the earth, 1nm = 1.8 km

UNCLOS

United Nations Convention on the Law of the Sea

Green water navy

Martinetime force operating in littorial zone (coast)

Blue water navy

It is a maritime force capable of operating across the deep waters of open oceans

9 dashed line

The area in the South China sea that China claims as their own territorial sea

Hydrocarbons

Organic compounds used for oil and polymergoods

Energy Security

The uninterrupted availability of energy sources at an affordable price

Naval power

Nations entire orginization for sea warefare

Longshore Drift

The movement of sediment along a coast by wave action; also called littoral drift

Retreating Coasts

Coasts along which the dominant processes are erosional, resulting in the coastline moving inland. Retreating coasts may also be caused by a positive change in sea level (sea level rise or a fall in land level)

Advancing Coasts

Depositional coasts that are growing as a consequence of sediment deposit and/or the infill of coastal marshes. Advancing coasts may also arise from a negative change in sea level (sea level fall or uplift of land)

Subaerial weathering

Describe events or features that are formed, located or taking place on the Earth's land surface and exposed to Earth's atmosphere

Eustatic Change

Changes in sea level

Isostatic change

Changes in the height of the lithosphere

Fetch

The distance traveled by wind or waves across open water

Corrasion / Abrasion

Materials being thrown onto a surface repeatedly overtime and eroding

Attrition

Materials colliding with one another through waves and eroding

Solution/ Corrosion

Chemicals in the water reacting with soluble minerals in the material in the sea

Hydraulic Action

High wave energy

Coral Reefs

A reef composed mainly of coral and other organic matter

Mangroves

Tropical zone with salt resistant plants

Concordant Coast

Coast with 1 rock type

Discordant Coast

Coast with more than one rock type

Lithology

Description of rock characteristics

Littoral/Longshore drift

Transportation of sediments onto coast at an angle caused by prevailing winds, swash and backwash

Swash

The rush of sea water up the beach after the breaking of a wave is called swash

Backwash

The motion of receding waves