The Hydrosphere The hydrosphere is the Earth s outer layer of water The distribution of water on Earth:

Transcription

1 The Hydrosphere

2 The Hydrosphere The hydrosphere is the Earth s outer layer of water The distribution of water on Earth:

3 Catchment Areas Catchment: All the area of land from which water empties into the same large body of water What factors do you think affect the amount of water that accumulates in a catchment area?

4 Factors affecting the flow and quality of water in a catchment:

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6 1) Topography : the shape, slope and terrain of the area A steeper slope may result in a faster flow 2) geology: the type, depth and structure of rock, ability of the soil to absorb the moisture Certain rocks and soil types are more absorbent than others

7 3) Climate : precipitation, temperature and winds 4) Vegetation: density and diversity of plant life. More plant life means greater absorption of runoff Removal of plant life leads to the erosion of soil which can increase the flow of water 5) Human activity such as agricultural, industrial and urban developments Water is diverted for these uses which can result in a decrease of water flow Human activity such as pollution can impact not only affect the immediate area, but also the area downstream of the disturbance.

8 Common Catchment Area Question X A D The chemicals enter the water at X and flow downstream past Remember village D and that into water the flows lake near downstream village C. Follow Villages the A flow and B of are water upstream from of the the point event of or contamination part of a different catchment B C If a chemical pollutant were to enter the catchment area at point X, which villages (A, B, C or D) would be affected and why?

9 The Oceans Oceans are divided by the continents: Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and the Southern Oceans Ocean waters are moved by currents that carry them all around the world

10 Ocean circulation An ocean current is the movement of seawater in a certain direction 2 main types of ocean currents: surface and subsurface currents Ocean circulation is the combined effect of all the currents that move across the ocean

11 1) Surface currents: mostly wind driven, they move horizontally. 2) Subsurface currents: mostly due to variations in density the colder the water, the denser it is, so it sinks and moves along the ocean floor. Also caused by differences in salinity: the more salt there is the denser it is.

12 Water Temperature 1) Water temperature is affected by the following a. Depth the deeper the water is, the less light there is, therefore the water is colder b. Seasons c. Latitude water near the equator is warmer than water near the poles

13 Salinity 2. Salinity is the amount of salt dissolved in a liquid and is affected by a. Heat and drought water evaporates = more salts in the water (raising the concentration of salts) b. Freezing Sea water salt is forced out of the ice crystals when sea ice forms(raising the concentration of salts) b. Melting pack ice and glaciers dilute the seawater and reduce the salt content

14 Thermohaline Circulation Thermohaline circulation: Huge conveyor belt formed by surface and subsurface currents that moves water all around the world.

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17 Thermohaline Circulation In the polar regions, cold surface water sinks to the bottom of the ocean floor and travels along the ocean floor When it gets to warmer regions (such as the equator) the water is heated and rises back up to the surface and then warm water travels along the surface towards the poles As it gets colder, heat is released into the air Thermohaline circulation regulates temperatures, preventing extreme cold at the poles and extreme heat around the equator.

18 The Cryosphere Consists of all the frozen water on Earth s surface 2 types of frozen water: 1) pack ice: Composed of seawater that has frozen in the winter expands during winter to cover about 5% of the northern oceans and 8% of the southern oceans is important to global ocean circulation and climate patterns Pack ice itself is now endangered because of global warming

19 Effects of melting pack ice Changes in recent decades have had profound effects, including the transition from cod to shrimp in Greenlandic waters. Changes in freshwater inputs to the North Atlantic may alter the global ocean currents with far-reaching effects on the global climate. The amount of solar energy absorbed by Arctic seas increases with large areas of open water. That causes even warmer seas. Warming temperatures are leading to the release of methane a powerful greenhouse gas from the seabed and melting tundra, wetlands and lakes in the Arctic. These changes could potentially impact global weather patterns and ocean circulation.

20 2) glaciers/icebergs/ice shelves: Frozen fresh water contains 79% of the world s freshwater reserves Melting ice caps/glaciers can cause: a raise sea levels, a loss of fresh water reserves, cause a decrease in salinity and density of the water