Hydrosphere

• Describes the Earth’s outer layer of water Represents all phases of water on the planet:

gas, liquid and solid

• What do you know about water on Earth?

Earth’s water

Salt water

Fresh water

97.5% of the Earth’s water

2.5% of the Earth’s water

GlaciersLakes, rivers, groundwater

79% of the fresh water

21% of the fresh water

Fresh water

• Examples:

Oceans• Defined by their great depth and salinity

• Temperature vary with depth, season and latitude

• Movement of the ocean is driven by ocean currents

• Name the Earth’s oceans:

Catchment Areas

• Inland waters are often described as catchment areas.

• A catchment area is a territory surrounding a waterway.

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A watershed is an area of land in which all inland waters drain into the same larger body of water.

Why is this important when we consider pollution?

Factors that will affect watersheds: • Topography: The steepness of the land surrounding the

area.

• Geology: the type of land and rock surrounding the area.

• Climate: rain or snow will affect the amount of water flowing into the area, as will the wind.

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• Vegetation: the presence of trees and plants will slow down the flow of water.

• Human disturbances: dams, agriculture and urban development.

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Pollution and Degradation

• Chemicals can be released into rivers, lakes streams and oceans and cause pollution. – Ex: Lake Baikal

• Warm water discharged from factories can also pollute.

– Alters the natural environment by changing the temperature and reduces the concentration of O2 present.

– This is called thermal pollution.

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Eutrophication• The process by which natural waters lose their

O2 because of an excessive amount of organic matter and nutrients.

• Occurs when there is an excess of phosphorus that enters rivers and lakes promoting algea growth.

• Read more on page 212 of your textbook.

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Eutrophication

• http://www.youtube.com/watch?v=UGqZsSuG7ao

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Threat At Sea

• Oil is responsible for 6 million tonnes of petroleum that is found in the oceans every year. – Accidental spills are only responsible for a small

proportion of this petroleum.

• Main causes: – Pumping oil from the ocean to land leads to leaking.

– Many oil reservoirs are routinely cleaned on the open seas.

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