Exploring the Hydrosphere: Earth's Water Systems in Depth

1. Structure of the Hydrosphere • Monday, November 7, 2011

2. The Big Picture • Around the continents... Oceans cover 2/3 of Earth’s surface! • On land...Water flows in rivers and streams and fills lakes and ponds! • Even underground... Water trickles through rock to create groundwater!

3. The Hydrosphere • HYDROSPHERE= the part of Earth containing water • most water in hydrosphere is liquid • salt water = about 97% (oceans) • fresh water = about 3% • frozen: ice caps, glaciers, snow, permafrost • liquid: groundwater, lakes, wetlands, rivers, atmosphere

4. Hydrosphere All Water Fresh Water

5. The Global Ocean • Oceans cover ~71% of Earth’s surface • All ocean water is connected in a global ocean • divided by continents into four major parts: • Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean

6. The Global Ocean

7. Ocean Size • The Pacific Ocean is the largest and deepest • covers 165 million square kilometers • average depth of 4,282 meters • deepest part = Marianas Trench region (about 11,033 meters deep!)

8. Ocean Size • Other oceans are smaller: • 2nd: Atlantic Ocean (half the volume of the Pacific!) • 3rd: Indian Ocean • Smallest: Arctic Ocean (much covered by sea ice)

9. Salinity • Salinity = the concentration of salts in a liquid, such as water • ocean water tastes salty because of dissolved salts • ordinary table salt = about 85% of these salts in oceans! • salinity increases as more salts are dissolved in water • ocean water has a salinity of about 3.5% • every 100g of ocean water contains average 3.5g of dissolved salts

10. Ocean Temperature • temperatures vary depending on latitude and depth • What parts of Earth receive the most sunlight and therefore more energy?

11. OceanTemperatures • The EQUATOR receives more direct sunlight and therefore receives more energy from the sun • Surface temps can reach 25°C • Near the poles temperatures tend to be near freezing • below a depth of 300m, water temperatures drop quickly as the sun no longer warms it • In the deepest parts of the oceans, temps range from 1°C to 4°C

12. Freshwater Resources • Most of Earth’s fresh water is frozen in polar ice caps • covers almost all of Antarctica • covers most of the Arctic Ocean, near the North Pole • Glacier = a mass of ice and snow that moves slowly over Earth’s surface • contain large amounts of frozen water

13. Fresh Water • Groundwater = water located below Earth’s surface • nearly 1/3 Earths fresh water • forms when surface water moves down through soils and sediment to collect in spaces between underground rock particles • aquifer = a rock layer that stores water and allows water to flow through it • drinking water and irrigation water often come from aquifers

14. Groundwater

15. Wetlands and Land Water • Most of Earth’s surface water is located in rivers, streams, lakes and wetlands • wetlands = land areas that remain wet for all or part of the year • act as sponges, collecting and holding rainwater to prevent flooding • also filter pollutants and sediment out of water • can improve the quality of water that will eventually become drinking water

16. Watersheds • watershed = an area of land where precipitation collects and then drains into a single collection place, often a lake or an ocean • sometimes called drainage basins, river basins • main function = move water from higher to lower elevations

17. Other Surface Waters • river = a large, flowing stream of water fed by other small streams • tributaries = smaller streams that feed rivers • lake = a low area of land where surface water run-off accumulates • vary in size

18. Think About it... • Why might groundwater be cleaner than surface water?