Chapter 11 Water

Properties of water that are important to know for Environmental Science Water is a polar molecule Surface tension Capillary action Water has a high heat capacity Water is most dense at 4°C (ice floats) Water’s boiling point is 100°C and its freezing point is 0°C condensation Light is absorbed by water it can only penetrate to about 200 meters Absorption of light heats up the water Water is a universal solvent Dissolved oxygen, CO 2 and other gases – amount increases as water temp increases Dissolved nutrients Dissolved pollutants and toxins Conductivity – measures amount of dissolved solids in water; ocean water has high conductivity due to all the salt Water is a powerful agent of erosion – wears away rocks, also carries sediment as long as it is flowing, when it slows down, it deposits the sediment Water evaporates as pure H 2 O, but water in the atmosphere can pick up pollutants (water cycle purifies water, but it can then become polluted by air pollutants) Water (like all things on earth) is subject to gravity and flows downhill Water can carry diseases Water is purified, filtered as it passes through sand, charcoal, gravel, rocks, even soil All living things on earth require water to survive

World Water Distribution Total: Total: 97% salt water 3% freshwater Freshwater: Freshwater: 70% glaciers 29% aquifers 1% lakes, rivers, streams

Section 3 – The Hydrosphere and Biosphere Hydrosphere – all the water on or near the Earth’s surface

Steps of the water cycle Water (or hydrologic) cycle – continuous movement of water into the air, onto land, and then back to water sources 1. Evaporation – liquid water is heated by the sun and then rises into the atmosphere (steam or humidity) 2. Condensation – water vapor forms water droplets on dust particles and form clouds or fog 3. Precipitation – large droplets fall from clouds in the form of rain, snow, sleet, or hail

Water (or Hydrologic) Cycle Processes in the water cycle: 1. Evaporation: liquid  gas with addition of heat 2. Condensation: gas  liquid when cools down 3. Precipitation: small drops collect into larger drops and fall to earth 4. Transpiration: water moves from plant leaves into air 5. Infiltration: water soaks into the ground, may go into groundwater

Locate the water storage locations on this diagram… Freshwater storage Freshwater storage Water storage in oceans Water storage in oceans Ground water storage Ground water storage Water (or Hydrologic) Cycle

Earth’s Oceans The Earth’s oceans cover over 70% of the Earth’s surface The Earth’s oceans cover over 70% of the Earth’s surface Ocean water –characterized by relatively high salt content Ocean water –characterized by relatively high salt content Salinity – the amount and concentration of salt in ocean water Salinity – the amount and concentration of salt in ocean water

Ocean Currents The ocean has movements of water similar to streams called currents. There are 2 different types of ocean currents. 1. Surface currents – occur near the surface of the ocean; they are driven by the wind 2. Deep currents – occur near the floor of the ocean; they are very slow moving and COLD Surface ocean currents 

A Global Temperature Regulator One of the most important functions of the ocean is to absorb and store energy from the sun One of the most important functions of the ocean is to absorb and store energy from the sun Ocean currents redistribute heat around the globe Ocean currents redistribute heat around the globe This function is what regulates the temperature of the Earth This function is what regulates the temperature of the Earth

Fresh Water Is different from oceans because it is not saline Only accounts for about 3% of all water on earth Include all of these: Icecaps and glaciers Icecaps and glaciers Rivers, lakes and wetlands Rivers, lakes and wetlands Groundwater Groundwater Aquifers Aquifers

Surface Water Lakes, rivers, streams, wetlands, estuaries Lakes, rivers, streams, wetlands, estuaries Watershed: the area of land that is drained by a river Watershed: the area of land that is drained by a river River system: the flowing network of water draining a river basin River system: the flowing network of water draining a river basin

Groundwater Groundwater: water that is beneath the earth’s surface Groundwater: water that is beneath the earth’s surface Water table: the upper level of water underground Water table: the upper level of water underground Aquifer: underground formation that contains groundwater Aquifer: underground formation that contains groundwater

Aquifers Most are made of materials like rock, sand, gravel with spaces in which the water can be held like a sponge (see pgs ) Most are made of materials like rock, sand, gravel with spaces in which the water can be held like a sponge (see pgs ) Water can be tapped from aquifers for use by people; if used too much and too quickly, it can go dry (Ogallala Aquifer case study, pgs ) Water can be tapped from aquifers for use by people; if used too much and too quickly, it can go dry (Ogallala Aquifer case study, pgs )

Aquifers Aquifers can be refilled as water percolates down through the recharge zone, may take a long time Aquifers can be refilled as water percolates down through the recharge zone, may take a long time Porosity – amount of space between particles of the rock Porosity – amount of space between particles of the rock Permeability – ability of the rock or soil to allow water to flow through it Permeability – ability of the rock or soil to allow water to flow through it Pollution can enter the groundwater through the recharge zone (think about Silent Spring) – it can then travel to other places through the underground water system, even showing up years later Pollution can enter the groundwater through the recharge zone (think about Silent Spring) – it can then travel to other places through the underground water system, even showing up years later

Water as a Resource Do you think water is a renewable resource? Do you think water is a renewable resource? It is a renewable resource because it can be replenished by nature (water cycle) It is a renewable resource because it can be replenished by nature (water cycle) However, if it is made unusable by pollution faster than nature can replenish it, then it is considered nonrenewable However, if it is made unusable by pollution faster than nature can replenish it, then it is considered nonrenewable Potable Water – water that is drinkable, usually following treatment. Potable Water – water that is drinkable, usually following treatment.

Biosphere The Biosphere – the narrow layer around Earth’s surface in which life can exist; from about 11km into the ocean, all of the earth’s surface and up to 9km in the atmosphere The Biosphere – the narrow layer around Earth’s surface in which life can exist; from about 11km into the ocean, all of the earth’s surface and up to 9km in the atmosphere

Requirements for life as we know it: Liquid water Liquid water Temps between 10°C and 40°C Temps between 10°C and 40°C Source of energy (sunlight in most cases, but chemical energy is another source) Source of energy (sunlight in most cases, but chemical energy is another source) Materials needed for growth must be cycled, through air, water, earth and organisms Materials needed for growth must be cycled, through air, water, earth and organisms

Is earth a closed or open system? Closed system: Closed system: Matter cannot enter Matter cannot enter Energy does enter Energy does enter Open system: Open system: Matter can enter Matter can enter Energy can enter Energy can enter Which type of system is this?

The Six Kingdoms of Living Things