Surface Water

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WATER
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Properties of Water
Universal Solvent
Water is the solvent of Life! Solute substance
dissolved in a solvent to form a solution
Solvent fluid that dissolves solutes Example
Ice Tea water is the solvent and tea and sugar
the solutes
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Properties of Water
Cohesion, Adhesion and Surface Tension
cohesion water attracted to other water

molecules because of polar properties
adhesion water attracted to other materials
surface tension water is pulled together
creating the
smallest surface area possible
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Properties of Water
Capillary Action
Because water has both adhesive and cohesive
properties, capillary action is present.
Capillary Action waters adhesive property is
the cause of capillary action. Water is
attracted to some other material and then through
cohesion, other water molecules move too as a
result of the original adhesion. Ex
Think water in a straw Ex Water
moves through trees this way
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Properties of Water
In order to raise the temperature of water, the
average molecular speed has to increase. It
takes much more energy to raise the temperature
of water compared to other solvents because
hydrogen bonds hold the water molecules
together! Water has a high heat capacity. The
specific heat is the amount of heat per unit mass
required to raise the temperature by one degree
Celsius.
High Heat Capacity
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Properties of Water
Density
Water is less dense as a solid! This is because
the hydrogen bonds are stable in ice each
molecule of water is bound to four of its
neighbors.
Solid water molecules are bonded together
space between fixed Liquid water molecules are
constantly bonding and rebonding space is
always changing
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Properties of Water
So, can you name all of the properties of water?
Adhesion Cohesion Capillary action High
surface tension Holds heat to regulate
temperature (High heat capacity) Less dense as a
solid than a liquid
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The ocean moderates coastal temperatures

• Water has high heat capacity, so it can absorb
  (or release) large quantities of heat without
  changing temperature
• Moderates coastal temperatures

Figure 5-6
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Salinity

• Salinity total amount of solid material
  dissolved in water
• Can be determined by measuring water conductivity
  
• Typically expressed in parts per thousand ()

Figure 5-15
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Constituents of ocean salinity

• Average seawater salinity 35
• Main constituents of ocean salinity
• Chloride (Cl)
• Sodium (Na)
• Sulfate (SO42)
• Magnesium (Mg2)

Figure 5-13
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Salinity variations
Location/type Salinity
Normal open ocean 33-38
Baltic Sea 10 (brackish)
Red Sea 42 (hypersaline)
Great Salt Lake 280
Dead Sea 330
Tap water 0.8 or less
Premium bottled water 0.3
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Processes affecting seawater salinity

• Processes that decrease seawater salinity
• Precipitation
• Runoff
• Icebergs melting
• Sea ice melting
• Processes that increase seawater salinity
• Sea ice forming
• Evaporation

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Surface salinity variation

• Pattern of surface salinity
• Lowest in high latitudes
• Highest in the tropics
• Dips at the Equator
• Surface processes help explain pattern

Figure 5-20
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Surface salinity variation

• High latitudes have low surface salinity
• High precipitation and runoff
• Low evaporation
• Tropics have high surface salinity
• High evaporation
• Low precipitation
• Equator has a dip in surface salinity
• High precipitation partially offsets high
  evaporation

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Seawater density

• Factors affecting seawater density
• Temperature ?, Density ? (inverse relationship)
• Salinity ?, Density ?
• Pressure ?, Density ?
• Temperature has the greatest influence on surface
  seawater density

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Water, Water Everywhere
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All freshwater comes from two sources

• Water that seeps below ground
• Some is taken up and used by plants
• Large amounts found in underground rock
  formations called aquifers

• Lakes, ponds, rivers, and streamsALL water above
  ground
• Most urban areas rely on surface water
• Supply resources and allow for travel/trade

• GROUND WATER

• SURFACE WATER

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Surface water movement Water Cycle

• Earths water supply is constantly recycled

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Surface Water Movement

• 1) Runoff
• Water flowing down slope along Earths surface or
  seep into the ground
• Run off speed determined by slope of the hill
• Ends up in a stream or lake, evaporate, or
  accumulate into puddles

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Movement

• Seep into ground
• Ground must have large enough pores loose soil
• Evaporate

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Fate of water Run off or Seep

• Certain characteristics will determine whether
  not water will either seep into or become runoff
• 1) Vegetation
• Vegetation allows for loose soil
• Loose soil allows water to enter ground
• Gardeners do not pack their soil

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Fate of water

• 2) Rate of precipitation
• Heavy
• soil clumps together closing pores
• Fills up ground to quickly and water becomes
  runoff
• Light
• allows water to gently slide through
• Less erosion

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Fate of Water

• 3) Soil Composition
• Effects the waters holding capacity
• Decayed organic matter (humus)
• Creates the pores in soil Increases retain
  ability
• Minerals
• Clay fine mineral which clump together
• Few Spaces
• Sand large pores

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Fate of Water

• 4) Slopes
• Steep allows for high runoff little absorption
• Little low runoff and high absorption

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Formation of Stream systems

• Runoff
• Surface water flows in thin sheets and eventually
  collects in small channels
• Runoff increases, channels widen and become
  deeper and longer
• Channels fill up again each time with rain
• Channel can become a stream

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• Water sheds
• drainage basin
• Land where all water drains into
• Divide
• High land area that separates watersheds

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Mississippi Watershed
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Stream Load

• All the materials that the stream carries
• Solution
• Material that has been dissolved
• Depends on area where the steam runs through
• Erosion of rocks and dirt

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Stream Load

• Suspension
• Small particles held up by the turbulence of
  stream
• Clay, silt, sand
• Depends on volume and velocity of water
• Bed Load
• Turbulence of water pushes heavy things
• Pebbles and cobbles
• Larger velocity large objects
• B/c of abrasion, rocks are smooth

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Stream Velocity Carrying Capacity

• Discharge width x depth x velocity (m) (m)
  (m/s)
• As discharge increases so does carrying capacity

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Floods

• Water fills over the sides of a stream banks
• Floodplain broad flat area of land that extends
  out from streams for excess flooding

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Freshwater Ecosystems
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Characteristics of a Freshwater Ecosystem

• Slow moving waters
• Low dissolved salt
• Plant and animal life depends on depth of water,
  rate of flow, and amounts of nutrients, sunlight,
  and oxygen
• Include lakes, ponds, rivers, and wetlands

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Lakes and Ponds
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Rivers

• START in mountainous regions
• Cold
• Shallow beds
• Highly oxygenated
• A rivers characteristics changes with geography,
  climate, and the runoff from nearby developments

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Wetlands

• Covered in water at least part of the year
• Trap and fix carbon
• Control flooding and absorb extra water when
  other bodies overflow
• Produce commercial products like seafood and
  berries (bogs)

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Freshwater Animal Adaptations
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Freshwater Plant Adaptations