chapter 8. biodiversity important ecological and economic services ◦ moderate atmospheric...
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Biodiversity
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
Degradation and decline◦ Coastal
development◦ Pollution◦ Overfishing◦ Warmer ocean
temperatures leading to coral bleaching
◦ Increasing ocean acidity
Fig. 8-11, p. 171
Gray reef shark
Sea nettle
Green sea turtle
Blue tang
Fairy bassletParrot fish
Sergeant major
Hard corals Algae Brittle star
Banded coral shrimpPhytoplankton
Symbiotic algae
Coney
Coney
ZooplanktonBlackcap basslet
Sponges
Moray eel
Bacteria
Producer to primary consumer
Primary to secondary consumer
Secondary to higher-level consumer
All consumers and producers to decomposers
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.
Aquatic life zones◦ Saltwater: marine
Oceans –Atlantic, Pacific, Arctic, Indian estuaries Coastlands and shorelines Coral reefs Mangrove forests
◦ Freshwater Lakes Rivers and streams Inland wetlands
Plankton – weakly swimming, free floating◦ Phytoplankton◦ Zooplankton◦ Ultraplankton – photosynthetic bacteria, 70% of
the primary productivity near the ocean surface
Nekton – strongly swimming consumers
Benthos – bottom dwellers,(oysters,clams,worms)
Decomposers- bacteria
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, or photic, zone
Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.
Fig. 8-4, p. 165
Marine Ecosystems
Economic Services
Climate moderation Food
CO2 absorption Animal and pet feed
Nutrient cycling Pharmaceuticals
Harbors and transportation routes
Waste treatment
Reduced storm impact (mangroves, barrier islands, coastal wetlands)
Coastal habitats for humans
RecreationHabitats and nursery areas Employment
Genetic resources and biodiversity
Oil and natural gas
Minerals
Scientific information Building materials
Ecological Services
NATURAL CAPITAL
Fig. 8-5, p. 166
Low tideCoastal Zone
Open Sea
Depth in meters
High tideSun
Sea level
50Estuarine Zone
Euphotic Zone
100
Ph
oto
syn
thes
is
Continental shelf
200
Bathyal Zone 500
1,000
Tw
ilig
ht
1,500
Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline .
Abyssal Zone
2,000
3,000
4,000
Dar
knes
s
5,000
10,000
0 5 10 15 20 25 30
0
Water temperature (°C)
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
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
Fig. 8-7a, p. 167
Herring gulls Peregrine falcon
Snowy egret Cordgrass
Short-billed dowitcher
Marsh periwinkle
PhytoplanktonSmelt
Zooplankton and small crustaceans
Soft-shelled clam
ClamwormBacteria
Producer to primary consumer
Primary to secondary consumer
Secondary to higher-level consumer
All consumers and producers to decomposers
Intertidal zone – area of shoreline between low and high tides◦ Rocky shores-◦ Sandy shores: barrier beaches
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
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 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
Major threats to marine systems ◦ 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
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.
Standing (lentic) bodies of freshwater◦ Lakes-vary in size , depth ,nutrient content◦ Ponds◦ Inland wetlands
Flowing (lotic) systems of freshwater◦ Streams◦ Rivers
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
Fig. 8-14, p. 174
NATURAL CAPITAL
Freshwater Systems
Ecological Services
Economic Services
Climate moderation Food
Nutrient cyclingDrinking water
Waste treatmentIrrigation water
Flood control
HydroelectricityGroundwater recharge
Habitats for many species
Transportation corridors
Genetic resources and biodiversity
Recreation
Scientific information Employment
Oligotrophic lakes◦ Low levels of nutrients and low NPP,
Eutrophic lakes◦ High levels of nutrients and high
Mesotrophic lakes – between the above 2 types
Cultural eutrophication ( human input of nutrients) leads to hypereutrophic lakes
Oligotrophic lakesLow levels of nutrients and low NPP, deep with steep banks. Water supplied by glaciers and mountain streams, crystal clear water
Crater Lake in Oregon
Fig. 8-16a, p. 175
Stepped Art
NPP- shallow, murky brown or green water with high turbidity.
Lake in Western New York State
The Effect of Nutrient Enrichment on a Lake
Surface water-precipitation that does not sink into the ground
Runoff – flows into stream
Watershed, drainage basin – land area that delivers runoff, sediment, dissolved substances
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
Waterfall
LakeGlacierRain and
snowRapids
Source Zone
Fig. 8-17, p. 176
Transition Zone
Tributary
Flood plainOxbow lake
Salt marsh
Delta Deposited sediment
Ocean
WaterSediment
Floodplain Zone
Stepped Art
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
Marshes – dominated by grasses and weeds
Swamps - dominated by trees and shrubs
Prairie potholes- depressions carved ot by ancient glaciers
Floodplains- excess water during heavy rains and floods
Arctic tundra in summer -
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
Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands.
Impact of dams and canals on rivers
Impact of flood control levees and dikes along rivers
Impact of pollutants from cities and farms on rivers
Impact of drained wetlands
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