Aquatic Biodiversity

1

• Chapter 8
• Aquatic Biodiversity

2
Most of the Earth Is Covered with Water (1)

• Saltwater global ocean divided into 4 areas
• Atlantic
• Pacific
• Arctic
• Indian
• Freshwater

3
Most of the Earth Is Covered with Water (2)

• Aquatic life zones
• Saltwater life zones (marine life zones)
• Oceans and estuaries
• Coastlands and shorelines
• Coral reefs
• Mangrove forests
• Freshwater life zones
• Lakes
• Rivers and streams
• Inland wetlands

4

• The ocean planet The salty oceans cover 71 of
  the earths surface and contain 97 of the
  earths water. Almost all of the earths water is
  in the interconnected oceans, which cover 90 of
  the planets ocean hemisphere (left) and nearly
  half of its land-ocean hemisphere (right).
  Freshwater systems cover less than 2.2 of the
  earths surface (Concept 8-1a).

5
Most Aquatic Species Live in Top, Middle, or
Bottom Layers of Water (1)

• Plankton free floating
• Phytoplankton
• Primary producers for most aquatic food webs
• Zooplankton
• Primary and secondary consumers
• Single-celled to large invertebrates like
  jellyfish
• Ultraplankton
• Tiny photosynthetic bacteria

6
Most Aquatic Species Live in Top, Middle, or
Bottom Layers of Water (2)

• Nekton
• Strong swimmers fish, turtles, whales
• Benthos
• Bottom dwellers oysters, sea stars, clams,
  lobsters, crabs
• Decomposers
• Mostly bacteria

7
Most Aquatic Species Live in Top, Middle, or
Bottom Layers of Water (3)

• Key factors in the distribution of organisms
• Temperature
• Dissolved oxygen content
• Availability of food
• Availability of light and nutrients needed for
  photosynthesis in the euphotic (photic) zone
• Turbidity degree of cloudiness in water
• Inhibits photosynthesis

8
Oceans Provide Vital Ecological and Economic
Resources

• Estimated 12 trillion per year in goods and
  services
• Reservoirs of diversity in three major life zones
• Coastal zone
• Warm, nutrient rich, shallow
• Shore to edge of continental shelf
• Usually high NPP from ample sunlight and
  nutrients
• Open sea
• Ocean bottom

9
Natural Capital
Marine Ecosystems
Ecological Services
Economic Services
Climate moderation
Food
CO 2 absorption
Animal and pet feed
Pharmaceuticals
Nutrient cycling
Harbors and transportation routes
Waste treatment
Reduced storm impact (mangroves, barrier islands,
coastal wetlands)
Coastal habitats for humans
Recreation
Habitats and nursery areas
Employment
Oil and natural gas
Genetic resources and biodiversity
Minerals
Building materials
Scientific information
Fig. 8-5, p. 172
10
Major Life Zones and Vertical Zones in an Ocean

Fig. 8-6, p. 173
11
Estuaries and Coastal Wetlands Are Highly
Productive (1)

• Estuaries and coastal wetlands
• Where rivers meet the sea
• Seawater mixes with freshwater
• Very productive ecosystems high nutrient levels
• River mouths
• Inlets
• Bays
• Sounds
• Salt marshes
• Mangrove forests

12
Estuaries and Coastal Wetlands Are Highly
Productive (2)

• Seagrass Beds
• Grow underwater in shallow areas
• Support a variety of marine species
• Stabilize shorelines
• Reduce wave impact
• Mangrove forests
• Along tropical and subtropical coastlines
• 69 different tree species that grow in saltwater

13
Estuaries and Coastal Wetlands Are Highly
Productive (3)

• Important ecological and economic services
• Coastal aquatic systems maintain water quality by
  filtering
• Toxic pollutants
• Excess plant nutrients
• Sediments
• Absorb other pollutants
• Provide food, timber, fuelwood, and habitats
• Reduce storm damage and coast erosion

14
Rocky and Sandy Shores Host Different Types of
Organisms

• Intertidal zone
• Rocky shores
• Sandy shores barrier beaches
• Organism adaptations necessary to deal with daily
  salinity and moisture changes
• Importance of sand dunes

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Living between the Tides
Rocky Shore Beach
Hermit crab
Shore crab
Sea star
High tide
Periwinkle
Sea urchin
Anemone
Mussel
Low tide
Sculpin
Barnacles
Kelp
Sea lettuce
Monterey flatworm
Nudibranch
Fig. 8-11a, p. 176
16
Living between the Tides
Beach ?ea
Barrier Beach
Peanut worm
Tiger beetle
Blue crab
Clam
Dwarf olive
High tide
Sandpiper
Ghost shrimp
Silversides
Low tide
Mole shrimp
White sand macoma
Sand dollar
Moon snail
Fig. 8-11b, p. 176
17
Coral Reefs Are Amazing Centers of Biodiversity

• Marine equivalent of tropical rain forests
• Habitats for one-fourth of all marine species

18
The Open Sea and Ocean Floor Host a Variety of
Species (1)

• Three vertical zones of the open sea
• Euphotic zone
• Phytoplankton
• Nutrient levels low
• Dissolved oxygen levels high
• Bathyal zone
• Dimly lit
• Zooplankton and smaller fishes

19
The Open Sea and Ocean Floor Host a Variety of
Species (2)

• Abyssal zone
• Dark and cold
• High levels of nutrients
• Little dissolved oxygen
• Deposit feeders
• Filter feeders
• Upwelling brings nutrients to euphotic zone
• Primary productivity and NPP

20
Human Activities Are Disrupting and Degrading
Marine Systems

• Major threats to marine systems
• Coastal development
• Overfishing
• Use of fishing trawlers
• Runoff of nonpoint source pollution
• Point source pollution
• Habitat destruction
• Introduction of invasive species
• Climate change from human activities
• Pollution of coastal wetlands and estuaries

21
Natural Capital Degradation
Major Human Impacts on Marine Ecosystems and
Coral Reefs
Marine Ecosystems
Coral Reefs
Ocean warming
Half of coastal wetlands lost to agriculture and
urban development
Rising ocean acidity
Over one-fifth of mangrove forests lost to
agriculture, development, and shrimp farms since
1980
Soil erosion
Algae growth from fertilizer runoff
Bleaching
Beaches eroding because of coastal development
and rising sea levels
Rising sea levels
Increased UV exposure
Ocean bottom habitats degraded by dredging and
trawler fishing
Damage from anchors
Damage from fishing and diving
At least 20 of coral reefs severely damaged and
2533 more threatened
Fig. 8-13, p. 179
22
Water Stands in Some Freshwater Systems and Flows
in Others (1)

• Standing (lentic) bodies of freshwater
• Lakes
• Ponds
• Inland wetlands
• Flowing (lotic) systems of freshwater
• Streams
• Rivers

23
Water Stands in Some Freshwater Systems and Flows
in Others (2)

• Four zones based on depth and distance from shore
• Littoral zone
• Near shore where rooted plants grow
• High biodiversity
• Turtles, frogs, crayfish, some fish
• Limnetic zone
• Open, sunlight area away from shore
• Main photosynthetic zone
• Some larger fish

24
Water Stands in Some Freshwater Systems and Flows
in Others (3)

• Profundal zone
• Deep water too dark for photosynthesis
• Low oxygen levels
• Some fish
• Benthic zone
• Decomposers
• Detritus feeders
• Some fish
• Nourished primarily by dead matter

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Natural Capital
Freshwater Systems
Ecological Services
Economic Services
Climate moderation
Food
Nutrient cycling
Drinking water
Waste treatment
Irrigation water
Flood control
Groundwater recharge
Hydroelectricity
Habitats for many species
Transportation corridors
Genetic resources and biodiversity
Recreation
Scientific information
Employment
Fig. 8-15, p. 181
26
Distinct Zones of Life in a Fairly Deep Temperate
Zone Lake
Fig. 8-16, p. 182
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Some Lakes Have More Nutrients Than Others

• Oligotrophic lakes
• Low levels of nutrients and low NPP
• Very clear water
• Eutrophic lakes
• High levels of nutrients and high NPP
• Murky water with high turbidity
• Mesotrophic lakes
• Cultural eutrophication of lakes from human input
  of nutrients

28
Freshwater Streams and Rivers Carry Water from
the Mountains to the Oceans

• Surface water
• Runoff
• Watershed, drainage basin
• Three aquatic life zones
• Source zone
• Transition zone
• Floodplain zone

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Lake
Glacier
Rain and snow
Headwaters
Rapids
Waterfall
Tributary
Flood plain
Oxbow lake
Salt marsh
Delta
Deposited sediment
Ocean
Source Zone
Transition Zone
Water
Sediment
Floodplain Zone
Fig. 8-18, p. 183
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Stepped Art
Fig. 8-18, p. 183
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Freshwater Inland Wetlands Are Vital Sponges (1)

• Marshes
• Swamps
• Prairie potholes
• Floodplains
• Arctic tundra in summer

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Freshwater Inland Wetlands Are Vital Sponges (2)

• Provide free ecological and economic services
• Filter and degrade toxic wastes
• Reduce flooding and erosion
• Help to replenish streams and recharge
  groundwater aquifers
• Biodiversity
• Food and timber
• Recreation areas

33
Human Activities Are Disrupting and Degrading
Freshwater Systems

• Impact of dams and canals on rivers
• Impact of flood control levees and dikes along
  rivers
• Impact of pollutants from cities and farms on
  streams, rivers, and lakes
• Impact of drained wetlands