9/29/2014 · 9/29/2014 7 Marine Ecosystems Subdivided into life zones Intertidal zone –land/sea...
Transcript of 9/29/2014 · 9/29/2014 7 Marine Ecosystems Subdivided into life zones Intertidal zone –land/sea...
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Chapter 6Major Ecosystems of the World
Overview of Chapter 6
PART 1
Earth’s Major Biomes
PART 2
Aquatic Ecosystems
Freshwater ecosystems
Estuaries
Marine Ecosystems
Interaction of Life Zones and Humans
Part 2: Aquatic Ecosystems
Fundamental Division:
Saltwater (Marine)
Freshwater
Aquatic ecosystems also affected by
Dissolved oxygen
Light penetration
Water chemistry (pH, salinity, etc.)
Water currents
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Aquatic Ecosystems
Three main categories of aquatic organisms
Plankton - free floating
Nekton - strong swimming
Benthos - bottom dwelling
Plankton Nekton Benthos
Freshwater Ecosystems
Include:
Rivers and streams
Lakes and ponds
Marshes and swamps
Represent 2% of earth’s surface
Assist in recycling water back to the oceans
Rivers and Streams
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Lakes and Ponds
Body of freshwater that does not flow
Three zones
Littoral
Limnetic
Profundal
Experience thermal stratification (depending on depth)
Lakes and Ponds
Littoral Zone - shallow water area along the shore
Limnetic Zone - open water beyond the littoral zone
Profundal Zone - beneath the limnetic zone of deep lakes
Lakes and Ponds
Littoral ZoneLimnetic Zone
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Thermal Stratification
Temperature changes sharply with depth
Thermocline
Temperature transition between warmer surface water and colder water at depth
Only present in warm months
Fall Turnover
Fall Turnover
Summer Winter
Echo Lake, California
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Marshes and Swamps
Lands covered by shallow, fresh water for at least part of the year
Historically filled in for development
Process called “Reclamation”
Current law recognizes their ecosystem services and ecological value
Flood protection, water purification, nesting habitat, etc.
Marshes and SwampsNapa-Sonoma Marsh
Marshes and SwampsNapa-Sonoma Marsh (Restoration)
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Marshes and SwampsNapa-Sonoma Marsh (After Restoration)
Estuaries
Where freshwater and saltwater mix
Highly variable environment
Temperature, salinity, depth of light penetration
Highly productive Nutrients transported
from land
High level of light
penetrates shallow water
Plants provide
photosynthetic carpet
Estuaries
San Francisco Bay (Estuary)
Largest estuary on west coast of United States
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Marine Ecosystems
Subdivided into life zones
Intertidal zone – land/sea interface
Benthic zone – sea bottom
Pelagic environment – open ocean
Tide pools Open ocean
Benthic Zone
Ocean floor, extending from tidal zone to deep sea trenches
Sediment is mostly mud
Burrowing worms and clams
Deep benthos Shallow benthos
Productive Benthic Communities
Seagrass Beds
Present to depth of 10 m
Provide food and habitat to ecosystem
Kelp Forest
60 m long brown algae found off rocky shores
Large Biodiversity
Coral Reefs
Built from accumulated layers of CaCO3
Colonies of millions of tiny coral animals
Found in shallow warm water
Most diverse of all marine environments
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SeagrassBed
Kelp Forest
Productive Benthic Communities
Coral Reef
Human Impacts on the Ocean