Transcript chapter8 2009

Chapter 8
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Biodiversity
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Important ecological and economic services
◦ Moderate atmospheric temperatures
◦ Act as natural barriers protecting coasts from
erosion
◦ Provide habitats
◦ Support fishing and tourism businesses
◦ Provide jobs and building materials
◦ Studied and enjoyed
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Degradation and
decline
Coastal development
Pollution
Overfishing
Warmer ocean
temperatures
leading to coral
bleaching
◦ Increasing ocean
acidity
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Gray reef shark
Sea nettle
Green sea
turtle
Parrot fish
Blue Fairy basslet
tang
Sergeant major
Hard corals Algae
Brittle
star
Banded coral
shrimp
Coney
Phytoplankton
Symbiotic
algae
Coney
Zooplankton
Blackcap basslet
Sponges
Moray
eel
Bacteria
Producer to
primary
consumer
Primary to
secondary
consumer
Secondary to
higher-level
consumer
All consumers
and producers
to decomposers
Fig. 8-11, p. 171
Saltwater and freshwater aquatic life zones
cover almost three-fourths of the earth’s
surface with oceans dominating the planet.
The key factors determining biodiversity in
aquatic systems are temperature, dissolved
oxygen content, availability of food and
availability of light and nutrients necessary
for photosynthesis.
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Aquatic life zones
◦ Saltwater: marine
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Oceans –Atlantic, Pacific, Arctic, Indian
estuaries
Coastlands and shorelines
Coral reefs
Mangrove forests
◦ Freshwater
 Lakes
 Rivers and streams
 Inland wetlands
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Plankton – weakly swimming, free floating
◦ Phytoplankton
◦ Zooplankton
◦ Ultraplankton – photosynthetic bacteria, 70% of the
primary productivity near the ocean surface
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Nekton – strongly swimming consumers
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Benthos – bottom dwellers,(oysters,clams,worms)
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Decomposers- bacteria
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Key factors in the distribution of organisms
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Temperature
Dissolved oxygen content
Availability of food
Availability of light and nutrients needed for
photosynthesis in the euphotic, or photic, zone
Saltwater ecosystems are irreplaceable
reservoirs of biodiversity and provide major
ecological and economic services.
NATURAL
CAPITAL
Marine Ecosystems
Ecological
Services
Economic
Services
Climate moderation
Food
CO2 absorption
Animal and pet feed
Nutrient cycling
Pharmaceuticals
Waste treatment
Harbors and
transportation routes
Reduced storm impact
(mangroves, barrier
islands, coastal
wetlands)
Habitats and nursery
areas
Genetic resources
and biodiversity
Scientific information
Coastal habitats for
humans
Recreation
Employment
Oil and natural gas
Minerals
Building materials
Fig. 8-4, p. 165
Sea level
0
50
Euphotic
Zone
Estuarine
Zone
Depth in
meters
100
Continental
shelf
200
Photosynthesis
Sun
Open
Sea
500
Bathyal Zone
1,000
Twilight
High tide
Low tide
Coastal
Zone
1,500
2,000
Abyssal
Zone
3,000
4,000
5,000
Darkness
Water temperature drops
rapidly between the
euphotic zone and the
abyssal zone in an area
called the thermocline .
10,000
0
5
10
15
20
Water temperature (°C)
25
30
Fig. 8-5, p. 166
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Estuaries and coastal
wetlands
◦ River mouths
◦ Inlets
◦ Bays
◦ Sounds
◦ Salt marshes
◦ Mangrove forests
Seagrass Beds
◦ Support a variety of
marine species
◦ Stabilize shorelines
◦ Reduce wave impact
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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
Herring gulls
Peregrine
falcon
Snowy
egret
Cordgrass
Short-billed
dowitcher
Marsh
periwinkle
Phytoplankton
Smelt
Zooplankton and
small crustaceans
Soft-shelled
clam
Producer to
primary
consumer
Bacteria
Primary to
secondary
consumer
Secondary to
higher-level
consumer
Clamworm
All consumers
and producers
to decomposers
Fig. 8-7a, p. 167
Fig. 8-7b, p. 167
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Intertidal zone – area of shoreline between low
and high tides
◦ Rocky shores◦ Sandy shores: barrier beaches
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Organism must be able to avoid be being swept
away or crushed by waves.
Must survive changing levels of salinity
Importance of sand dunes – first line of defense
against ravages of the sea
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Vertical zones of the open sea
◦ Euphotic zone-brightly lit upper zone, 40% of the
world’s photosynthetic activity, nutrient levels low , DO
high, predatory fish
◦ Bathyal zone- dimly lit middle zone, smaller fishes
◦ Abyssal zone: dark,cold,low DO
◦ receives marine snow – dead and decaying organisms
 Deposit feeders
 Filter feeders
◦ Upwellings
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Primary productivity and NPP /unit area low, but
the seas cover so much of the earth’s surface ,it
is the largest contributor to earth’s overall NPP
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Major threats to marine systems
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Coastal development
Overfishing
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
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Largest estuary –US
Increased population
Point/Nonpoint sources
High phosphate/nitrate
Overfishing
1960 –polluted
1983-Chesapeake Bay
Program
Freshwater ecosystems provide major
ecological and economic services and are
irreplaceable reservoirs of biodiversity.
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Standing (lentic) bodies of freshwater
◦ Lakes-vary in size , depth ,nutrient content
◦ Ponds
◦ Inland wetlands
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Flowing (lotic) systems of freshwater
◦ Streams
◦ Rivers
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Formation of lakes
Four zones based on depth and distance from
shore
◦ Littoral zone – near shore, shallow sunlit waters to
the depth at which rooted plants stop growing ,
high biodiversity
◦ Limnetic zone- open, sunlit surface away from
shore, sunlight extends to the depth , main source
of photosynthesis, microscopic plankton
◦ Profundal zone-deep ocean water, very dark, low
DO
◦ Benthic zone – bottom of the lake, decomposers,
detritus feeder nourished by dead matter that falls
from littoral zone
NATURAL CAPITAL
Freshwater Systems
Ecological
Services
Climate moderation
Nutrient cycling
Economic
Services
Food
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. 8-14, p. 174
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Oligotrophic lakes
◦ Low levels of nutrients and low NPP,
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Eutrophic lakes
◦ High levels of nutrients and high
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Mesotrophic lakes – between the above 2
types
Cultural eutrophication ( human input of
nutrients) leads to hypereutrophic lakes
Oligotrophic lakes
Low levels of nutrients
and low NPP, deep with
steep banks. Water
supplied by glaciers and
mountain streams,
crystal clear water
Crater Lake in Oregon
The Effect of Nutrient Enrichment
on a Lake
NPP- shallow, murky
brown or green water with
high turbidity.
Lake in Western New York
State
Stepped Art
Fig. 8-16a, p. 175
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Surface water-precipitation that does not sink
into the ground
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Runoff – flows into stream
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Watershed, drainage basin – land area that
delivers runoff, sediment, dissolved substances
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Three aquatic life zones
◦ Source zone – head waters, clear cold, fast flowing
◦ Transition zone wider, deeper, warmer streams
◦ Floodplain zone – flow across flat valleys, higher
temperatures, muddy, high concentrations of silt
Rain and
snow
Lake
Glacier
Rapids
Waterfall
Tributary
Flood plain
Oxbow lake
Salt marsh
Delta Deposited
sediment
Ocean
Source Zone
Transition Zone
Floodplain Zone
Water
Sediment
Stepped Art
Fig. 8-17, p. 176
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Coastal deltas, mangrove
forests, and coastal
wetlands: natural
protection against storms
Dams and levees reduce
sediments in deltas:
significance?
New Orleans, Louisiana,
and Hurricane Katrina:
August 29, 2005
Global warming, sea rise,
and New Orleans
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Marshes – dominated by grasses and weeds
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Swamps - dominated by trees and shrubs
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Prairie potholes- depressions carved ot by
ancient glaciers
Floodplains- excess water during heavy rains and
floods
Arctic tundra in summer -
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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
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Human activities threaten biodiversity and
disrupt ecological and economic services
provided by freshwater lakes, rivers, and
wetlands.
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Impact of dams and canals on rivers
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Impact of flood control levees and dikes
along rivers
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Impact of pollutants from cities and farms on
rivers
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Impact of drained wetlands
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Loss of wetlands has led to
◦ Increased flood and drought damage
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Lost due to
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Growing crops
Mining
Forestry
Oil and gas extraction
Building highways
Urban development