IB Geography Option B

El nino

Reversal of normal atmospheric circulation of southern pacific ocean.

It involves the warming of eastern pacific and occurs at intervals of 2 and 10 yrs

La nina

intermittent cold current = intensification of normal conditions = cold south america and cold upwellings of water in the south pacific.

Ocean acidification

• results from increased CO2

• more acidic oceans kill coral and therefore biodiversity

• acidification reduces calcification in coral, resulting in slower growth and weaker skeletons

• carbonic acid…

Carbon cycle

• The ocean os the worlds largest carbon sink

• photosynthesis - CO2 - organic material.

• photosynthesis by phytoplankton creates organic compounds, feeding and sustaining the food chain and in the end are decomposed, releasing CO2.

• transfer of CO2 from the ocean to the atmosphere takes a long time to completely cycle round.

Eustatic change

When sea level changes due to alteration in the volume of water in oceans (or a change in the amount of water the ocean holds)

It happens during an ice age.

The shape of ocean basins can change due to techtonic movement. This has a global effect global effect

Isostatic change

Occurs because of an increase or decrease in the height of the land.

When the height of the land increases, sea level falls and when height of the land decreases, sea level rises.

This is a local change

Advancing coastline

Emerged coastlines where the rate of deposition is rapid

Retreating coastline

Occurs in submerged coasts where rate of erosion exceeds rate of deposition

Both advancing and retreating coastlines result from sea level change and erosion