Aquatic Biodiversity

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• Aquatic Biodiversity

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Core Case StudyWhy Should We Care About Coral
Reefs?
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Coral Bleaching
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AQUATIC ENVIRONMENTS

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

Figure 6-2
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AQUATIC ENVIRONMENTS
Figure 6-3
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Red most productivity and Purple nearly empty
of life
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Nutrients trapped on ocean floor move up with an
upwelling
Winds blowing across the ocean surface often push
water away from an area. When this occurs, water
rises up from beneath the surface to replace the
diverging surface water. This process is known as
upwelling.
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Nutrients brought to the euphotic zone used by
phytoplankton
The thermocline blocks the upwelling and prevents
nutrients from reaching the euphotic zone (this
is observed to occur during an El Nino)
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Why is there more nutrients available in the cold
arctic waters than the warm tropical waters?
Warm water (less density than cold water)
Cold water (more density than warm water
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Red most productive Purple least productive
Notice the connection between SST and primary
productivity
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Infra Red radiation, Visible Light, and UV
radiation as its wavelengths are absorbed as
depth increases
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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)
• Nekton fish, turtles, whales.
• Benthos bottom dwellers (barnacles, oysters).
• Decomposers breakdown organic compounds (mostly
  bacteria).

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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.

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Marine Ecosystems

• 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 Where Most of the Action Is

• The coastal zone the warm, nutrient-rich,
  shallow water that 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 but contains 90 of all marine
  species.
• Provides numerous ecological and economic
  services.
• Subject to human disturbance.

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The Coastal Zone
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Biological Zones in the Open SeaLight Rules

• Euphotic zone brightly lit surface layer.
• Nutrient levels low, dissolved O2 high,
  photosynthetic activity.
• Bathyal zone dimly lit middle layer.
• No photosynthetic activity, zooplankton and fish
  live there and migrate to euphotic zone to feed
  at night.
• Abyssal zone dark bottom layer.
• Very cold, little dissolved O2.

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Estuaries and Coastal Wetlands Centers of
Productivity

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

Figure 6-7
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Mangrove Forests

• Are found along about 70 of gently sloping sandy
  and silty coastlines in tropical and subtropical
  regions.

Figure 6-8
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Estuaries and Coastal Wetlands Centers of
Productivity

• 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.

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Rocky and Sandy Shores Living with the Tides

• Organisms experiencing daily low and high tides
  have evolved 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.

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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
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Barrier Islands

• Low, narrow, sandy islands that form offshore
  from a coastline.
• Primary and secondary dunes on gently sloping
  sandy barrier beaches protect land from erosion
  by the sea.

Figure 6-10
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Threats to Coral ReefsIncreasing Stresses

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

Figure 6-11
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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
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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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Natural Capital Degradation
Marine Ecosystems
Half of coastal wetlands lost to agriculture and
urban development Over one-third of mangrove
forests lost to agriculture, development, and
aquaculture shrimp farms Beaches eroding because
of coastal development and rising sea
level Ocean bottom habitats degraded by dredging
and trawler fishing At least 20 of coral reefs
severely damaged and 3050 more threatened
Fig. 6-13, p. 136
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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
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Natural Capital
Natural Capital
Freshwater Systems
Economic Services
Ecological Services
Climate moderation Nutrient cycling Waste
treatment Flood control Groundwater
recharge Habitats for many species Genetic
resources and biodiversity Scientific information
Food Drinking water Irrigation
water Hydroelectricity Transportation
corridors Recreation Employment
Fig. 6-14, p. 136
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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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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.

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Sunlight
Painted turtle
Green frog
Blue-winged teal
Muskrat
Pond snail
Littoral zone
Limnetic zone
Diving beetle
Plankton
Profundal zone
Benthic zone
Northern pike
Yellow perch
Bloodworms
Fig. 6-15, p. 137
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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
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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.

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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.

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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
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Rain and snow
Glacier
Lake
Rapids
Waterfall
Tributary
Oxbow lake
Flood plain
Salt marsh
Deposited sediment
Delta
Ocean
Source Zone
Transition Zone
Water
Sediment
Floodplain Zone
Fig. 6-17, p. 139
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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.

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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.

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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.

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The End
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Guess what I am thinking.