Aquatic Environments

1
Section 7-1

• Aquatic Environments

2
Core Case StudyWhy Should We Care About Coral
Reefs?

• Coral reefs form in clear, warm coastal waters of
  the tropics and subtropics.
• Formed by massive colonies of polyps.
• Finding Nemo

Figure 6-1
3
Fig. 6-1a, p. 126
4
Fig. 6-1b, p. 126
5
Core Case StudyWhy Should We Care About Coral
Reefs?

• Help moderate atmospheric temperature by removing
  CO2 from the atmosphere.
• Act as natural barriers that help protect 14 of
  the worlds coastlines from erosion by battering
  waves and storms.
• Provide habitats for a variety of marine
  organisms.

6
AQUATIC ENVIRONMENTS

• Saltwater and freshwater aquatic life zones cover
  almost three-fourths of the earths surface

Figure 6-2
7
AQUATIC ENVIRONMENTS
Figure 6-3
8
WATERS IMPORTANCE, AVAILABILITY, AND RENEWAL

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

Figure 14-2
9
Categorization of Aquatic Biomes

• Physical characteristics
• Salinity
• Depth
• Water flow
• Temperature (not used for categorization)

10
Types of Biomes

• Freshwater
• Streams
• Rivers
• Lakes
• Wetlands
• Marine (saltwater)
• Estuaries
• Coral Reefs
• Open Ocean

11
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).

12
Phytoplankton

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

13
Zooplankton

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

14
Nekton

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

15
Benthos

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

16
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.
• The Ocean

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Section 7-2

• Saltwater Life Zones

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SALTWATER LIFE ZONES

• The oceans that occupy most of the earths
  surface provide many ecological and economic
  services.
• Scientists estimate that marine systems provide
  21 trillion in goods and services per year 70
  more than terrestrial ecosystems.

Figure 6-4
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The Coastal Zone

• The coastal zone
• The warm, nutrient-rich, shallow water
• Extends from the high-tide mark on land to the
  gently sloping, shallow edge of the continental
  shelf.
• The coastal zone makes up less than 10 of the
  worlds ocean area
• Contains 90 of all marine species.
• Provides numerous ecological and economic
  services.
• Subject to human disturbance.

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The Coastal Zone
Figure 6-5
21
Estuaries and Coastal Wetlands

• Estuaries include river mouths, inlets, bays,
  sounds, salt marshes in temperate zones and
  mangrove forests in tropical zones.

Figure 6-7
22
Estuaries and Coastal Wetlands

• Estuaries and coastal marshes provide ecological
  and economic services.
• Filter toxic pollutants, excess plant nutrients,
  sediments, and other pollutants.
• Reduce storm damage by absorbing waves and
  storing excess water produced by storms and
  tsunamis.
• Provide food, habitats and nursery sites for many
  aquatic species.

23
Rocky and Sandy Shores

• Organisms experiencing daily low and high tides
  have a number of ways to survive under harsh and
  changing conditions.
• Gravitational pull by moon and sun causes tides.
• Intertidal Zone area of shoreline between low
  and high tides.

24
Rocky and Sandy Shores Living with the Tides

• Organisms in intertidal zone develop specialized
  niches to deal with daily changes in
• Temperature
• Salinity
• Wave action

Figure 6-9
25
Threats to Coral ReefsIncreasing Stresses

• Biologically diverse and productive coral reefs
  are being stressed by human activities.

Figure 6-11
26
Natural Capital Degradation
Coral Reefs
Ocean warming Soil erosion Algae growth from
fertilizer runoff Mangrove destruction Bleaching
Rising sea levels Increased UV
exposure Damage from anchors Damage from
fishing and diving
Fig. 6-12, p. 135
27
Effects of Human Activities on Marine Systems
Red Alert

• Human activities are destroying or degrading many
  ecological and economic services provided by the
  worlds coastal areas.

Figure 6-13
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Section 7-3

• Freshwater Life Zones

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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
30
Flowing Water Ecosystems

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

31
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
32
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
33
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.

34
Downstream Characteristics

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

35
Energy Source

• Gravity

36
Standing Water Ecosystems

• Lakes, ponds, etc.

37
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.

38
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).

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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.

40
Limnetic Zone

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

41
Profundal Zone

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

42
Lakes Water-Filled Depressions
Figure 6-15
43
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.
• What causes this overturning?

44
Thermal Stratification

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

45
Causes of Thermal Stratification

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

46
Thermocline

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

47
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.

48
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.

49
Freshwater Wetlands
50
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
51
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.

52
Marshes

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

53
Swamps

• A lowland region permanently covered with water.

54
Prairie Potholes

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

55
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.

56
Importance of freshwater wetlands

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

57
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.

58
Estuaries
59
Estuary Definition

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

60
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.

61
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.

62
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.

63
Overview Questions

• What are the basic types of aquatic life zones
  and what factors influence the kinds of life they
  contain?
• What are the major types of saltwater life zones,
  and how do human activities affect them?
• What are the major types of freshwater life
  zones, and how do human activities affect them?