Water Quality Notes

1
Water
2
WATERS IMPORTANCE, AVAILABILITY, AND RENEWAL

• Water keeps us alive, moderates climate, sculpts
  the land, removes and dilutes wastes and
  pollutants, and moves continually through the
  hydrologic cycle.
• Only about 0.02 of the earths water supply is
  available to us as liquid freshwater.

3
WATERS IMPORTANCE, AVAILABILITY, AND RENEWAL

• Comparison of population sizes and shares of the
  worlds freshwater among the continents.

Figure 14-2
4
WATERS IMPORTANCE, AVAILABILITY, AND RENEWAL

• Some precipitation infiltrates the ground and is
  stored in soil and rock (groundwater).
• Water that does not sink into the ground or
  evaporate into the air runs off (surface runoff)
  into bodies of water.
• The land from which the surface water drains into
  a body of water is called its watershed or
  drainage basin.

5

Unconfined Aquifer Recharge Area
Evaporation and transpiration
Evaporation
Precipitation
Confined Recharge Area
Runoff
Flowing artesian well
Recharge Unconfined Aquifer
Stream Well requiring a pump
Water table
Infiltration
Lake
Infiltration
Unconfined aquifer
Less permeable material such as clay
Confined aquifer
Confining impermeable rock layer
Fig. 14-3, p. 308
6
WATERS IMPORTANCE, AVAILABILITY, AND RENEWAL

• We currently use more than half of the worlds
  reliable runoff of surface water and could be
  using 70-90 by 2025.
• About 70 of the water we withdraw from rivers,
  lakes, and aquifers is not returned to these
  sources.
• Irrigation is the biggest user of water (70),
  followed by industries (20) and cities and
  residences (10).

7
The Water Resource
8
Importance

• Leonardo da Vinci said that Water is the driver
  of nature. Without water, the other nutrient
  cycles would not exist in their present forms,
  and current forms of life on earth could not
  exist.

9
Hydrogen Bonds
10
Attraction Between Molecules

• The strong forces of attraction between molecules
  of water.

11
Heat Capacity

• Water changes temp very slowly because it can
  store heat. This protects living organisms from
  the shock of abrupt temperature changes.

12
Heat of Vaporization

• The temperature at which water turns to vapor.

13
Universal Solvent

• Water can dissolve a wide variety of compounds.
  This means it can easily become polluted by
  water-soluble wastes.

14
Expansion When Frozen

• Ice has a lower density than liquid water. Thus,
  ice floats on water.

15
Niches
16
What Kinds of Organisms Live in Aquatic Life
Zones?

• Aquatic systems contain floating, drifting,
  swimming, bottom-dwelling, and decomposer
  organisms.
• Plankton important group of weakly swimming,
  free-floating biota.
• Phytoplankton (plant), Zooplankton (animal),
  Ultraplankton (photosynthetic bacteria)
• Necton fish, turtles, whales.
• Benthos bottom dwellers (barnacles, oysters).
• Decomposers breakdown organic compounds (mostly
  bacteria).

17
Phytoplankton

• Description small drifting plants
• Niche they are producers that support most
  aquatic food chains
• Example cyanobacteria many types of algae

18
Zooplankton

• Description herbivores that feed on
  phytoplankton or other zooplankton
• Niche food stock for larger consumers
• Example krill small crustaceans

19
Nekton

• Description larger, strong-swimming consumers
• Niche top consumers in the aquatic ecosystem
• Example fish, turtles, and whales

20
Benthos

• Description bottom-dwelling creatures
• Niche primary consumers, decomposers
• Example barnacles, oysters, and lobsters

21
Freshwater Ecosystems
22
FRESHWATER LIFE ZONES

• Freshwater life zones include
• Standing (lentic) water such as lakes, ponds, and
  inland wetlands.
• Flowing (lotic) systems such as streams and
  rivers.

Figure 6-14
23
Flowing Water Ecosystems

• Because of different environmental conditions in
  each zone, a river is a system of different
  ecosystems.

24
Natural Capital
Ecological Services of Rivers

• Deliver nutrients to sea to help sustain
  coastal fisheries
• Deposit silt that maintains deltas
• Purify water
• Renew and renourish wetlands
• Provide habitats for wildlife

Fig. 12-11, p. 267
25
Freshwater Streams and RiversFrom the Mountains
to the Oceans

• Water flowing from mountains to the sea creates
  different aquatic conditions and habitats.

Figure 6-17
26
Headwater Stream Characteristics

• A narrow zone of cold, clear water that rushes
  over waterfalls and rapids. Large amounts of
  oxygen are present. Fish are also present. Ex.
  trout.

27
Downstream Characteristics

• Slower-moving water, less oxygen, warmer
  temperatures, and lots of algae and
  cyanobacteria.

28
Energy Source

• Gravity

29
Standing Water Ecosystems

• Lakes, ponds, etc.

30
Life in Layers

• Life in most aquatic systems is found in surface,
  middle, and bottom layers.
• Temperature, access to sunlight for
  photosynthesis, dissolved oxygen content,
  nutrient availability changes with depth.
• Euphotic zone (upper layer in deep water
  habitats) sunlight can penetrate.

31
Lakes Water-Filled Depressions

• Lakes are large natural bodies of standing
  freshwater formed from precipitation, runoff, and
  groundwater seepage consisting of
• Littoral zone (near shore, shallow, with rooted
  plants).
• Limnetic zone (open, offshore area, sunlit).
• Profundal zone (deep, open water, too dark for
  photosynthesis).
• Benthic zone (bottom of lake, nourished by dead
  matter).

32
Littoral Zone

• A shallow area near the shore, to the depth at
  which rooted plants stop growing. Ex. frogs,
  snails, insects, fish, cattails, and water lilies.

33
Limnetic Zone

• Open, sunlit water that extends to the depth
  penetrated by sunlight.

34
Profundal Zone

• Deep, open water where it is too dark for
  photosynthesis.

35
Thermal Stratification
36
Lakes Water-Filled Depressions
Figure 6-15
37
Definition

• The temperature difference in deep lakes where
  there are warm summers and cold winters.

38
Lakes Water-Filled Depressions

• During summer and winter in deep temperate zone
  lakes the become stratified into temperature
  layers and will overturn.
• This equalizes the temperature at all depths.
• Oxygen is brought from the surface to the lake
  bottom and nutrients from the bottom are brought
  to the top.

39
Causes

• During the summer, lakes become stratified into
  different temperature layers that resist mixing
  because summer sunlight warms surface waters,
  making them less dense.

40
Thermocline

• The middle layer that acts as a barrier to the
  transfer of nutrients and dissolved oxygen.

41
Fall Turnover

• As the temperatures begin to drop, the surface
  layer becomes more dense, and it sinks to the
  bottom. This mixing brings nutrients from the
  bottom up to the surface and sends oxygen to the
  bottom.

42
Spring Turnover

• As top water warms and ice melts, it sinks
  through and below the cooler, less dense water,
  sending oxygen down and nutrients up.

43
Freshwater Wetlands
44
Freshwater Inland Wetlands Vital Sponges

• Inland wetlands act like natural sponges that
  absorb and store excess water from storms and
  provide a variety of wildlife habitats.

Figure 6-18
45
Freshwater Inland Wetlands Vital Sponges

• Filter and degrade pollutants.
• Reduce flooding and erosion by absorbing slowly
  releasing overflows.
• Help replenish stream flows during dry periods.
• Help recharge ground aquifers.
• Provide economic resources and recreation.

46
Marshes

• An area of temporarily flooded, often silty land
  beside a river or lake.

47
Swamps

• A lowland region permanently covered with water.

48
Hardwood Bottomland Forest

• An area down by a river or stream where lots of
  hardwoods, like oaks, grow.

49
Prairie Potholes

• These are depressions that hold water out on the
  prairie, especially up north in Canada. It is a
  very good duck habitat.

50
Peat Moss Bog

• A wet area that over time fills in (the last
  stage of succession is peat moss). It can be
  very deep. In Ireland, they burn this for wood.

51
Importance of freshwater wetlands

• They filter purify water.
• Habitat for many animals and plants.

52
Historical Aspects

• Developers and farmers want Congress to revise
  the definition of wetlands. This would make
  60-75 of all wetlands unavailable for
  protection. The Audubon Society estimates that
  wetlands provide water quality protection worth
  1.6 billion per year, and they say if that
  wetlands are destroyed, the U.S. would spend 7.7
  billion to 31 billion per year in additional
  flood-control costs.

53
Estuaries
54
Definition

• A partially enclosed area of coastal water where
  sea water mixes with freshwater.

55
Salt Marshes

• The ground here is saturated with water and there
  is little oxygen, so decay takes place slowly.
  It has a surface inlet and outlet, and contains
  many invertebrates. It is also the breeding
  ground for many ocean animals. Ex. crabs and
  shellfish.

56
Mangrove Forests

• These are along warm, tropical coasts where there
  is too much silt for coral reefs to grow. It is
  dominated by salt-tolerant trees called mangroves
  (55 different species exist). It also helps to
  protect the coastline from erosion and provides a
  breeding nursery for some 2000 species of fish,
  invertebrates, and plants.

57
Importance of Estuaries

• Just one acre of estuary provides 75,000 worth
  of free waste treatment, and has a value of about
  83,000 when recreation and fish for food are
  included.
• Prime Kansas farmland has a top value of 1,200
  and an annual production value of 600.

58
The Everglades

• Southern Florida to the Keys

59
Case Study Restoring the Florida Everglades

• The worlds largest ecological restoration
  project involves trying to undo some of the
  damage inflicted on the Everglades by human
  activities.
• 90 of parks wading birds have vanished.
• Other vertebrate populations down 75-95.
• Large volumes of water that once flowed through
  the park have been diverted for crops and cities.
• Runoff has caused noxious algal blooms.

60
Problems

• As Miami develops, it encroaches on everglades.
  Plus, it prompts people vs. wildlife. It is
  freshwater and local areas are draining it.

61
Restoring the Florida Everglades

• The project has been attempting to restore the
  Everglades and Florida water supplies.

Figure 12-10
62
Restoration

• Build huge aqueduct, or find other sources of
  fresh water an protect it federally under
  endangered species act, etc.

63
Hydrologic Cycle
64
Surface Water

• Examples streams, rivers, and lakes
• Source precipitation
• Watershed Ex. small streams ? larger streams ?
  rivers ? sea

65
Groundwater

• Aquifersporous rock w/ water flowing through
• Water Table the level of earths land crust to
  which the aquifer is filled
• Renewability the circulation rate of
  groundwater is slow (300 to 4,600 years).

66
Water Usage

• Irrigation watering crops
• Industry coolant (power plant)
• Domestic and Municipal drinking, sewage,
  bathwater, dishwater laundry

67
Problems
68
Too Much Water

• Problems include flooding, pollution of water
  supply, and sewage seeping into the ground.

69
TOO MUCH WATER

• Heavy rainfall, rapid snowmelt, removal of
  vegetation, and destruction of wetlands cause
  flooding.
• Floodplains, which usually include highly
  productive wetlands, help provide natural flood
  and erosion control, maintain high water quality,
  and recharge groundwater.
• To minimize floods, rivers have been narrowed
  with levees and walls, and dammed to store water.

70
TOO MUCH WATER

• Comparison of St. Louis, Missouri under normal
  conditions (1988) and after severe flooding
  (1993).

Figure 14-22
71
TOO MUCH WATER

• Human activities have contributed to flood deaths
  and damages.

Figure 14-23
72
Too Little Water
73
Examples

• Examples include drought and expanding deserts.

74
Overdrawing Surface Water

• Lake levels drop, recreation use drops, fisheries
  drop, and salinization occurs. Ex. Soviet Union
  (Aral Sea) the inland sea drained the river that
  fed into it. Now its a huge disaster (read pg.
  322 in text).

1997
1964
75
Case Study The Aral Sea Disaster

• Diverting water from the Aral Sea and its two
  feeder rivers mostly for irrigation has created a
  major ecological, economic, and health disaster.
• About 85 of the wetlands have been eliminated
  and roughly 50 of the local bird and mammal
  species have disappeared.
• Since 1961, the seas salinity has tripled and
  the water has dropped by 22 meters most likely
  causing 20 of the 24 native fish species to go
  extinct.

76
Aquifer Depletion

• This harms endangered species, and salt water can
  seep in.

77
Salinization of Irrigated Soil

• Water is poured onto soil and evaporates. Over
  time, as this is repeated, nothing will grow
  there anymore.

78
U.S. Water Problems
79
Surface Water Problems

• The polluted Mississippi River (non-source point
  pollution) has too much phosphorus.
• In the Eerie Canal, which connects the ocean to
  the Great Lakes, lampreys came in and depleted
  the fish. The zebra mollusk is also a problem in
  the Great Lakes.

80
Effects of Plant Nutrients on LakesToo Much of
a Good Thing

• Plant nutrients from a lakes environment affect
  the types and numbers of organisms it can support.

Figure 6-16
81
Effects of Plant Nutrients on LakesToo Much of
a Good Thing

• Plant nutrients from a lakes environment affect
  the types and numbers of organisms it can
  support.
• Oligotrophic (poorly nourished) lake Usually
  newly formed lake with small supply of plant
  nutrient input.
• Eutrophic (well nourished) lake Over time,
  sediment, organic material, and inorganic
  nutrients wash into lakes causing excessive plant
  growth.

82
Effects of Plant Nutrients on LakesToo Much of
a Good Thing

• Cultural eutrophication
• Human inputs of nutrients from the atmosphere and
  urban and agricultural areas can accelerate the
  eutrophication process.

83
Mono Lake

• (like the Dead Sea) This has a huge salt
  concentration due to mans draining.

84
Colorado River Basin

• These are dams reservoirs that feed from the
  Colorado River all the way to San Diego, LA, Palm
  Springs, Phoenix Mexico. So far has worked
  because they havent withdrawn their full
  allocations. See pg306.

85
The Colorado River Basin

• The area drained by this basin is equal to more
  than one-twelfth of the land area of the lower 48
  states.

Figure 14-14
86
Case Study The Colorado Basin an Overtapped
Resource

• The Colorado River has so many dams and
  withdrawals that it often does not reach the
  ocean.
• 14 major dams and reservoirs, and canals.
• Water is mostly used in desert area of the U.S.
• Provides electricity from hydroelectric plants
  for 30 million people (1/10th of the U.S.
  population).

87
Case Study The Colorado Basin an Overtapped
Resource

• Lake Powell, is the second largest reservoir in
  the U.S.
• It hosts one of the hydroelectric plants located
  on the Colorado River.

Figure 14-15
88
Groundwater Problems

• These include pollution, salt, and draining too
  much.

89
Other Effects of Groundwater Overpumping

• Sinkholes form when the roof of an underground
  cavern collapses after being drained of
  groundwater.

Figure 14-10
90
Groundwater Depletion A Growing Problem

• Areas of greatest aquifer depletion from
  groundwater overdraft in the continental U.S.

• The Ogallala, the worlds largest aquifer, is
  most of the red area in the center (Midwest).

Figure 14-8
91
Ogallala Aquifer

• This is the worlds largest known aquifer, and
  fuels agricultural regions in the U.S. It
  extends from South Dakota to Texas. Its
  essentially a non-renewable aquifer from the last
  ice age with an extremely slow recharge rate. In
  some cases, water is pumped out 8 to 10 times
  faster than it is renewed. Northern states will
  still have ample supplies, but for the south its
  getting thinner. It is estimated that ¼ of the
  aquifer will be depleted by 2020.

92
Global Water Problems
93
Impacts of Human Activities on Freshwater Systems

• Dams, cities, farmlands, and filled-in wetlands
  alter and degrade freshwater habitats.
• Dams, diversions and canals have fragmented about
  40 of the worlds 237 large rivers.
• Flood control levees and dikes alter and destroy
  aquatic habitats.
• Cities and farmlands add pollutants and excess
  plant nutrients to streams and rivers.
• Many inland wetlands have been drained or filled
  for agriculture or (sub)urban development.

94
Core Case Study A Biological Roller Coaster Ride
in Lake Victoria

• Lake Victoria has lost their endemic fish species
  to large introduced predatory fish.

Figure 12-1
95
Core Case Study A Biological Roller Coaster Ride
in Lake Victoria

• Reasons for Lake Victorias loss of biodiversity
• Introduction of Nile perch.
• Lake experienced algal blooms from nutrient
  runoff.
• Invasion of water hyacinth has blocked sunlight
  and deprived oxygen.
• Nile perch is in decline because it has eaten its
  own food supply.

96
Stable Runoff

• As water runs off from rain, its supposed to get
  into rivers, and finally off to the sea. But
  when we dam rivers, less goes to the ocean,
  meaning the brackish water (where the river hits
  the ocean) becomes more salty. This is the
  breeding ground for many fish and invertebrates.
  This harms the ecology of the area.

97
Drinking Water Problems
98
Coliform Bacteria

• The W.H.O. recommends there be zero colonies of
  bacteria per 100ml of drinking water and 200
  colonies per 100ml of swimming water. The
  average human excretes 2 billion organisms per
  day (see how easily untreated sewage can
  contaminate water?).

99
Oxygen Demanding Wastes

• These are organic wastes that can be decomposed
  by aerobic bacteria (causes lack of oxygen).
  Fish die as a result of a lack of oxygen.

100
Water-Soluble Inorganic Chemicals

• These include acids, salts, mercury, and lead.
  They make water unfit to drink.

101
Organic Material

• These include oil, gas, plastics, pesticides, and
  detergents.

102
Population Growth

• Problems include over-drawing fresh water,
  pollution, and over-building so that water cant
  seep into the ground.

103
Sharing Water Resources

• There are water wars out west. California bought
  the water from the Colorado River, but Arizona
  wants it. Who owns it? The same thing is
  happening in Texas. More water rights are sold
  than the actual amount of water. How do you
  share water? This is a problem all over the
  world.

104
Water Management
105
Dams and Reservoirs

• Description A dammed stream that can capture
  store water from rain melted snow.
• Benefits Hydroelectric power provides water
  to towns recreation controls floods downstream
• Problems Reduces downstream flow prevents
  water from reaching the sea (Colorado River)
  devastates fish life reduces biodiversity.

106
USING DAMS AND RESERVOIRS TO SUPPLY MORE WATER

• Large dams and reservoirs can produce cheap
  electricity, reduce downstream flooding, and
  provide year-round water for irrigating cropland,
  but they also displace people and disrupt aquatic
  systems.

107

Provides water for year-round irrigation of
cropland
Flooded land destroys forests or cropland and
displaces people
Large losses of water through evaporation
Provides water for drinking
Downstream cropland and estuaries are deprived of
nutrient-rich silt
Reservoir is useful for recreation and fishing
Risk of failure and devastating downstream
flooding
Can produce cheap electricity (hydropower)
Downstream flooding is reduced
Migration and spawning of some fish are disrupted
Fig. 14-13a, p. 317
108
Case Study Chinas Three Gorges Dam

• There is a debate over whether the advantages of
  the worlds largest dam and reservoir will
  outweigh its disadvantages.
• The dam will be 2 kilometers long.
• The electric output will be that of 18 large
  coal-burning or nuclear power plants.
• It will facilitate ship travel reducing
  transportation costs.
• Dam will displace 1.2 million people.
• Dam is built over seismatic fault and already has
  small cracks.

109
Dam Removal

• Some dams are being removed for ecological
  reasons and because they have outlived their
  usefulness.
• In 1998 the U.S. Army Corps of Engineers
  announced that it would no longer build large
  dams and diversion projects in the U.S.
• The Federal Energy Regulatory Commission has
  approved the removal of nearly 500 dams.
• Removing dams can reestablish ecosystems, but can
  also re-release toxicants into the environment.

110
Water Diversion

• Description Damming a river to control where
  the water flows
• Benefits Keeps water where we want it- cities!
• Problems Drains wetlands, destroys land

111
Desalinization

• Description Removing salt from salt water
• Benefits Freshwater
• Problems Uses lots of energy costs 3-5Xs more
  money what do we do with the salt?

112
DESALTING SEAWATER, SEEDING CLOUDS, AND TOWING
ICEBERGS AND GIANT BAGGIES

• Removing salt from seawater by current methods is
  expensive and produces large amounts of salty
  wastewater that must be disposed of safely.
• Distillation heating saltwater until it
  evaporates, leaves behind water in solid form.
• Reverse osmosis uses high pressure to force
  saltwater through a membrane filter.

113
DESALTING SEAWATER, SEEDING CLOUDS, AND TOWING
ICEBERGS AND GIANT BAGGIES

• Seeding clouds with tiny particles of chemicals
  to increase rainfall towing icebergs or huge bags
  filled with freshwater to dry coastal areas have
  all been proposed but are unlikely to provide
  significant amounts of freshwater.

114
Harvesting Icebergs

• Description Towing massive icebergs to arid
  coastal areas (S. California Saudi Arabia)
• Benefits freshwater
• Problems Technology not available costs too
  high raise temperatures around the earth.

115
INCREASING WATER SUPPLIES BY WASTING LESS WATER

• Sixty percent of the worlds irrigation water is
  currently wasted, but improved irrigation
  techniques could cut this waste to 5-20.
• Center-pivot, low pressure sprinklers sprays
  water directly onto crop.
• It allows 80 of water to reach crop.
• Has reduced depletion of Ogallala aquifer in
  Texas High Plains by 30.

116
Conservation

• Description Saving the water we have
• Methods recycling conserving at home
  xeriscaping fix leaks
• Benefits Saves money Saves Wildlife
• Problems bothersome to people lack of caring
  laziness

117
Importance of the Ocean Environment
Marine Ecology
118
Area

• Saltwater makes up 97 of the water on earth

Life There are 250,000 known species of marine
plants and animals, many are food for other
organisms, like us.
119
Temperature

• Solar heat is distributed by ocean currents as
  ocean water evaporates.
• The oceans are major players in the earths
  climate are a gigantic reservoir for carbon
  dioxide therefore they help regulate the temp.
  of the troposphere.

120
Zones of the Marine Environment

• Two major zones that break up into smaller zones
  coastal and the open sea

121
Intertidal or Beach Zone

• Broken up into five areas

122
Lower Shoreface

• The deepest part of the beach farther into the
  water, before the breaker bar that forms waves

123
Upper Shoreface

• Shallow zone where the waves begin to form

124
Forebeach

• Contains the swash zone place where the waves
  crash.

125
Backbeach

• Only under water during high tide

126
Fore-Island Dunes

• Sand dunes doesn't flood often, except during
  hurricanes, etc. Constantly changing due to the
  wind

127
Estuary

• Where fresh water and salt water meet

An estuary is a coastal body of water, partly
surrounded by land, with access to the open ocean
and a large supply of fresh water from a river
128
Characteristics
129
Salinity

• Salinity fluctuates with tidal cycles, the time
  of year, precipitation. The organisms that live
  here must be able to tolerate these conditions

130
Fertility of Estuaries

• Estuaries are the most fertile ecosystems in the
  world
• Greater productivity than either the adjacent
  ocean or the fresh water upriver

131
Reasons for High Fertility

• Nutrients are transported from the land into
  rivers that flow into the estuary
• Tidal action circulates nutrients and helps
  remove wastes
• A high level of light due to shallow water
• Many plants provide an extensive photosynthetic
  carpet

132
Difficulties

• Sandy beach Life must deal with a shifting
  environment that threatens to engulf them no
  protection against wave action. Most animals
  bury into the sand. They move with the tides, so
  theyre always underwater dont dry out.

133
Difficulties (Continued)

• Rocky shore high wave action at high tide
  drying out temperature changes during low.
  Animals have a way of sealing in moisture like
  a shell find a way to cling to the rocks so
  they dont get washed away with waves.

134
Pelagic
The Open Ocean

• The open ocean environment divided into neritic
  (open ocean from the shoreline to a depth of
  200m) and oceanic provinces (depths gt 200m).

135
Euphotic Zone

• Lots of light. From 0 - 200 meters.
  Photosynthesis takes place here.

136
Bathyal Zone

• The dimly lit part of ocean. From 200 - 1500
  meters.

137
Benthic Characteristics (ocean floor)

• The ocean floor consists of sediments (mostly
  sand and mud)
• Many marine animals, like worms and clams, burrow
  
• Bacteria are common can go down 500 meters
  below ocean floor. The Benthic environment
  extends from the shore to the deep.

138
Sea Grass Beds

• Flowering plants that have adapted to complete
  submersion in salty water.

139
Location of sea grass

• Found in shallow water to depths of 10 meters
  where they can photosynthesize. Sea grasses are
  found in quiet, temperate, tropical, and
  subtropical waters not in polar waters.

Examples
Eel, turtle, and manatee grass.
140
Ecological Importance

• Reduce surface erosion, provide food, provide
  habitats for many marine organisms.
• Animals that eat sea grass are manatees, green
  turtles, parrotfish, sturgeon fish, and sea
  urchins.

141
Abyssal Zone

• Completely dark. Extends to a depth of 4000 to
  6000 meters (2.5 to 3.7 miles). Water here is
  very cold has little dissolved oxygen.

142
Kelp

• The largest of the brown algae, many reach
  lengths of 60 meters (200 feet). Common in cooler
  water are found along rocky coasts. Provide
  habitat for many animals like tubeworms, sponges,
  clams, fish, mammals. Some animals eat the
  kelp.

143
Characteristics
Coral Reefs

• Built from layers of calcium carbonate, coral
  reefs are found in warm, shallow sea water. The
  living portions must grow in shallow waters where
  light hits. They are the most diverse of all
  marine ecosystems.

144
Examples

• Many coral reefs are made of red coralline algae
  that photosynthesize.
• Others have zooxanthellae (symbiotic algae) that
  live and photosynthesize in their tissues.
• Not all corals have zooxanthellae, but only those
  with it build reefs.
• Coral animals also capture food at night with
  stinging tentacles that paralyze zooplankton and
  small animals that drift nearby.

145
Coral Reef Waters

• The waters where coral reefs are found are often
  poor in nutrients. Yet, other factors are
  favorable such as temperature, sunlight year
  round, and zooxanthellae.

146
Growth

• Coral reefs grow slowly as one dies, another
  organism grows on it.

147
Fringing Reef
Types of Coral Reefs

• The most common type of coral reef. It is
  directly attached to the shore of a volcanic
  island or continent.

148
(No Transcript)
149
                                                
                                          Fringing
Reef Bora Bora NASA JPL Satellite Space Shuttle
Sensor SIR-C/X-SAR
150
Atoll

• A circular reef that surrounds a central lagoon
  of quiet water.
• An atoll forms on top of the cone of a submerged
  volcanic island.
• More than 300 atolls are found in the Pacific
  and Indian Oceans.

151
(No Transcript)
152
                           View of Midway Atoll
from Space Shuttle
153
                                                
                            Atolls in The
Maldives Landsat 7
154
Barrier Reef

• A lagoon of open water separates the land from
  the barrier reef.
• The largest barrier reef is the Great Barrier
  Reef off the coast of Australia.
• The second largest is off the coast of Belize.

155
(No Transcript)
156
(No Transcript)
157
Provides a Habitat
Ecological Importance of Coral Reefs

• Provides a habitat for a wide variety of marine
  organisms.

158
Coastline Protection

• Protects coasts from shoreline erosion.

159
Benefits for Humans

• Provides humans with seafood, pharmaceuticals,
  and recreational/tourism dollars