Quick questions on Biophysical processes producing dynamics and change: HSC Geography

Solar radiation warms the equator more than the poles, creating a temperature gradient that drives the global circulation. Warm air rises at the equator (the Hadley cell), creating low pressure and high rainfall in the tropics. Air descends at around 30 degrees latitude, creating high pressure and the world's dry zones, including central Australia.

Evaporation, transpiration, condensation, precipitation, runoff, infiltration, percolation, storage. The cycle continuously redistributes fresh water across the planet. Over the Murray-Darling Basin, around 530 mm of average rainfall falls each year; around 94 percent of that returns to the atmosphere through evaporation and transpiration before reaching a river.

Convection in the mantle drives the movement of lithospheric plates at rates of around 1-10 cm per year. Plate boundaries produce earthquakes, volcanoes, and mountain building. Australia sits in the middle of the Indo-Australian plate, which is moving north-east at around 7 cm per year. Most Australian earthquakes are low magnitude (e.g.

Weathering breaks rock in place by physical, chemical, or biological processes. Erosion removes the weathered material by water, wind, ice, or gravity. The Twelve Apostles along Victoria's Great Ocean Road show mechanical wave action eroding soft Miocene limestone at rates of around 2 cm per year. Sandstone cliffs in the Blue Mountains are exfoliating through pressure release as overlying rock erodes away.

Nitrogen, phosphorus, carbon, and other elements move between atmosphere, soil, plants, and animals. Nitrogen-fixing bacteria in eucalypt root nodules pull nitrogen from the air; leaf fall returns it to soil; soil microbes mineralise it back to plant-available forms.

Soil forms through weathering of parent rock plus organic matter inputs plus time. The five soil-forming factors (climate, organisms, relief, parent material, time) explain why soils in the Pilbara (Fe-rich, thin) differ from soils on the Atherton Tableland (basalt-derived, deep, fertile).