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Aquatic Biodiversity
Chapter 8
Core Case Study: Why Should We Care about Coral Reefs? (1)
Biodiversity
Formation
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
Core Case Study: Why Should We Care about Coral Reefs? (2)
Degradation and decline• Coastal development• Pollution• Overfishing• Warmer ocean temperatures leading to coral
bleaching• Increasing ocean acidity
A Healthy Coral Reef in the Red Sea
8-1 What Is the General Nature of Aquatic Systems?
Concept 8-1A Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface with oceans dominating the planet.
Concept 8-1B 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.
Most of the Earth Is Covered with Water (1)
Saltwater: global ocean divided into 4 areas• Atlantic• Pacific• Arctic• Indian
Freshwater
Most of the Earth Is Covered with Water (2)
Aquatic life zones• Saltwater: marine • Oceans and estuaries• Coastlands and shorelines• Coral reefs• Mangrove forests
• Freshwater• Lakes• Rivers and streams• Inland wetlands
The Ocean Planet
Fig. 8-2, p. 163
Ocean hemisphere Land–ocean hemisphere
Distribution of the World’s Major Saltwater and Freshwater Sources
Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1)
Plankton• Phytoplankton• Zooplankton• Ultraplankton
Nekton
Benthos
Decomposers
Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (2)
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
8-2 Why Are Marine Aquatic Systems Important?
Concept 8-2 Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.
Oceans Provide Important Ecological and Economic Resources
Reservoirs of diversity in three major life zones• Coastal zone• Usually high NPP
• Open sea• Ocean bottom
Major Ecological and Economic Services Provided by Marine Systems
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
Natural Capital: Major Life Zones and Vertical Zones in an Ocean
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 Are Highly Productive (1)
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
Estuaries and Coastal Wetlands Are Highly Productive (2)
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
View of an Estuary from Space
Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area
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
Fig. 8-7b, p. 167
Mangrove Forest in Daintree National Park in Queensland, Australia
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
Living between the Tides
Fig. 8-9, p. 169
Rocky Shore Beach
Sea star Hermit crab Shore crab
High tide
Periwinkle
Sea urchin AnemoneMussel
Low tideSculpin
Barnacles
Kelp Sea lettuce
Monterey flatwormBeach fleaNudibranch
Peanut worm Tiger beetle
Barrier Beach
Blue crab ClamDwarf olive
High tide
SandpiperGhost shrimpSilversides Low tide Mole
shrimp
White sand macoma
Sand dollar
Moon snail
Beach flea
Peanut worm Tiger beetle
Barrier Beach Blue crab ClamDwarf olive
High tide
SandpiperGhost shrimpSilversides Low tide Mole
shrimp
White sand macoma
Sand dollar
Moon snail
Fig. 8-9, p. 169
Rocky Shore BeachSea star Hermit
crab Shore crab
High tide
Periwinkle
Sea urchin AnemoneMussel
Low tideSculpin
Barnacles
KelpSea lettuce
Monterey flatworm
Nudibranch
Stepped Art
Primary and Secondary Dunes
Fig. 8-10, p. 170
Ocean Beach Primary Dune
Trough Secondary Dune
Back Dune Bay or Lagoon
Recreation, no building
Walkways, no building
Limited recreation and
walkways
Walkways, no building
Most suitable for development
Recreation
Grasses or shrubs
Bay shore
Taller shrubsTaller shrubs and trees
Coral Reefs Are Amazing Centers of Biodiversity
Marine equivalent of tropical rain forests
Habitats for one-fourth of all marine species
Natural Capital: Some Components and Interactions in a Coral Reef Ecosystem
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
The Open Sea and Ocean Floor Host a Variety of Species
Vertical zones of the open sea• Euphotic zone• Bathyal zone• Abyssal zone: receives marine snow• Deposit feeders• Filter feeders
• Upwellings
Primary productivity and NPP
Animation: Ocean provinces
Video: Elephant seals
Video: Florida reefs
Video: Giant clam
Video: Reef fish (Bahamas)
Video: Schooling fish
Video: Sea anemones
Video: Sea lions
Video: Sting rays
8-3 How Have Human Activities Affected Marine Ecosystems?
Concept 8-3 Human activities threaten aquatic biodiversity and disrupt ecological and economic services provided by saltwater systems.
Human Activities Are Disrupting and Degrading Marine Systems
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
Case Study: The Chesapeake Bay—an Estuary in Trouble (1)
Largest estuary in the US; polluted since 1960
Population increased
Point and nonpoint sources raised pollution
Phosphate and nitrate levels too high
Case Study: The Chesapeake Bay—an Estuary in Trouble (2)
Overfishing
1983: Chesapeake Bay Program• Update on recovery of the Bay• Should we introduce an Asian oyster?
Chesapeake Bay
Video: ABC News: Beach pollution
8-4 Why Are Freshwater Ecosystems Important?
Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.
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
Water Stands in Some Freshwater Systems and Flows in Others (2)
Formation of lakes
Four zones based on depth and distance from shore• Littoral zone• Limnetic zone• Profundal zone• Benthic zone
Major Ecological and Economic Services Provided by Freshwater Systems
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
Distinct Zones of Life in a Fairly Deep Temperate Zone Lake
Fig. 8-15, p. 175
Sunlight
Painted turtle
Blue-winged teal
Green frog
Muskrat
Pond snail Littoral zone Plankton
Limnetic zoneProfundal zoneDiving beetle Benthic zone
Northern pike
Yellow perch Bloodworms
Some Lakes Have More Nutrients Than Others
Oligotrophic lakes• Low levels of nutrients and low NPP
Eutrophic lakes• High levels of nutrients and high NPP
Mesotrophic lakes
Cultural eutrophication leads to hypereutrophic lakes
The Effect of Nutrient Enrichment on a Lake
Fig. 8-16a, p. 175
Stepped Art
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
Three Zones in the Downhill Flow of Water
Fig. 8-17, p. 176
LakeGlacierRain and
snowRapids
WaterfallTributary
Flood plainOxbow lake
Salt marsh
Delta Deposited sediment
Source ZoneOcean
Transition Zone
WaterSediment
Floodplain Zone
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
Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans
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
New Orleans, Louisiana, (U.S.) and Hurricane Katrina
Projection of New Orleans if the Sea Level Rises 0.9 Meter
Freshwater Inland Wetlands Are Vital Sponges (1)
Marshes
Swamps
Prairie potholes
Floodplains
Arctic tundra in summer
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
Active Figure: Lake zonation
Animation: Lake turnover
Animation: Trophic natures of lakes
Video: River flyover
8-5 How Have Human Activities Affected Freshwater Ecosystems?
Concept 8-5 Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands.
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 rivers
Impact of drained wetlands
Case Study: Inland Wetland Losses in the United States
Loss of wetlands has led to• Increased flood and drought damage
Lost due to• Growing crops• Mining• Forestry• Oil and gas extraction• Building highways• Urban development