Transcript Ecology 15 Freshwater, Marine and Wetland Systems Global

Ecology 15
Freshwater, Marine and
Wetland Systems
Global Climate Change
Ralph Kirby
Freashwater and Estuarine
Ecosystems
Water that falls on land and does not enter the soil or evaporate
must create surface water systems
Gravity forms streams then rivers
These create basins, ponds, lakes floodplains and wetlands
Watershed
– Area of land drained by a stream or river
Catchment
– Ponds, lakes and wetlands that retain water for a long time
Lotic
– Flowing water ecosystems
Streams
Rivers
Lentic
– Nonflowing water ecosystems
Ponds
Lakes
Inland wetlands
Lakes and Ponds
Multiple origins
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Glacial
Tectonic
Subsidence
From rivers and streams by silting up
Animals
Humans
Inland depression holding standing water
– Large range of depths
1 meter to 2000 meters
– Large range of sizes
< 1 hectare to >1000 square kilometers
Ponds have rooted plants over most of area
Lake and pond ecosystems have well defined boundaries
– Dependent on light and therefore depth
Affected by silt and phytoplankton
Oxygen limitation
– Littoral zone
Where light reaches the botomn
– Limnetic zone
Where light penetrates, but not to botomn
– Frofundal zone
Water where light does not support photosynthesis
– Benthic zone
Bottom zone
Littoral Zone
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Greatest diversity
Specialization
Many animal species
Provides a large input of organic matter into the whole system
Limnetic Zone
Dominated by planktonic organisms
– Phytoplankton
– Zooplankton
Seasonal variations
Limited by light
Phytoplankton limits it’s own light
– Thus limnetic zone become shallower as summer progresses
Phytoplankton specialiation based on depth and
temperature
Zooplankton can usually move and therefore may laos
be stratified
Spring and Autumn turnovers move plankton downwards
and organic matter upwards
Fish are usually top predators
– Influenced by food supply, oxygen and temperature
Profundal Zone
Limited life
– Lack of oxygen
– Lack of light
– Low temperature
Some fish
Some plankton, especially zooplankton
Benthic Zone
Where decomposition occurs
Great biological activity
Dominated by anaerobic microorganisms
As it approaches the surface, it changes
– Influence of plants, water movement, light, etc
Eutrophication
Input of organic
matter can
change structure
of a lake
Increases
plankton
Decreases
oxygen
Changes
temperature
profile
Affects Epiimnion
Human
intervention is
very important in
this
– Can occur
naturally
– Fertilizers and
addition of
exotic species
can also cause
this
Flowing Water Communities
Velocity is very
important
Geography determines
the structure and
speed of flow
Speed usually higher
nearer the sources
Speed is reduced on
entering a larger body
of water
– Silt drop
Life adapts to the
speed of the stream
Four major feeding
groups in a stream
community
Flowing water systems are a continuous community
Flowing water systems change from the headwaters to the mouth
– Vegetation changes
– Plankton changes
– Animals change
Dams have a major effect on flowing water system
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Create lakes
Slows water flow
Changes spiraling
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Reduce flooding
Removes silt
Multiple Dams can compound effects
Three Gorges Project
Freshwater eventually joins the marine environment
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Estuary
Sediment drop
Mixed environment
Salinity
Water flow in both directions
Marine Ecosystems
Zonation and Stratification
– Pelagic Zone
Photic zone
– Light
Mesopelagic
– Light limited
Bathypelagic
– Dark
Neritic province – Continental Shelf
Oceanic province
– Benthic Zone
System varies with season and latitude
Surface of pelagic
– Phytoplankton
dominates
Great diversity in
species and size
– Zooplankton major
herbivore
– Bacteria also
important
– Fish very important
in Nekton province
Benthos
Unique World
– Surface and
subsurface living
organisms
– Energy from
decomposition
– Energy from
hydrothermal
vents
Black smokers
– 300-450oC
White smokers
– +300oC
High in minerals
Hyperthermophilic
organisms
– Bacteria
– Worms
Seashores
Rocky shore
– Complex environment
Wave action
– Attachment
Tides
– How often
Oxygen
High diversity
Sandy or muddy shores
– Harsh
No place to attach
Life is hidden
Based on organic matter
Rocky Shore
Sandy shore
Complexity of a coastal ecosystem
Coral Reefs
High productivity
Very high diversity
Mixture of coastal and deepwater system
Wetlands
Area covered with water and supporting aquatic plants
Very wide variety of types
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Vary with periodicity of flooding
Vary with saturation
Vary with oxygen availability
Salinity
Geography
Global Environmental Changes
Evidence
Results