AQUATIC ECOSYSTEMS

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AQUATIC ECOSYSTEMS
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What are the basic needs of aquatic biota
(organisms)?

• CO2
• O2
• Sunlight
• Nutrients- food minerals

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Types of Aquatic Ecosystems

• Freshwater Ecosystems
• Standing Water- lakes ponds
• Moving Water- rivers streams
• Transitional Communities
• Estuaries
• Wetlands- bogs/fens, swamps, marshes
• Marine Ecosystems
• Shorelines
• Barrier Islands
• Coral Reefs
• Open Ocean

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Freshwater Ecosystems

• Usually 0.005 salt
• Some exceptions
• Great Salt Lakes-
• 5-27 salt
• Dead Sea- 30 salt
• Moving water- high elevations cold high O2
  trout streamlined plants
• Standing water- lower elevations warmer less
  O2 bass, amphibians cattails, rushes
• Why would there be less oxygen in standing water?

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Plankton

• Plankton is a general term for the tiny,
  free-floating organisms that live in both
  freshwater and saltwater environments.
• Unicellular algae, or phytoplankton, are
  supported by nutrients in the water and form the
  base of many aquatic food webs.
• Planktonic animals, or zooplankton, feed on the
  phytoplankton.

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Transitional Communities
Delta

• ESTUARIES
• Where freshwater dumps into ocean
• Brackish water (less salty than seawater)
• Has rich sediments that often form deltas
• Productive biodiverse
• Organisms adapted to varying levels of salinity
  as tide ebbs flows
• Nursery for larval forms of many aquatic
  species of commercial fish shellfish

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Transitional Communities

• WETLANDS
• Land saturated at least part of the year
• Swamps- have trees like bald cypress high
  productivity
• Marshes- no trees tall grasses high
  productivity
• Bogs/Fens- may or may not have trees waterlogged
  soil with lots of peat low productivity
• Fens- fed by groundwater surface runoff
• Bogs- fed by precipitation

Swamp
Marsh
Bog
Fen
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Importance of Wetlands

• Highly productive- get lots of sunlight, ? plants
  
• ? animals
• Nesting, breeding ground for migratory birds
• Slows flooding by absorbing runoff
• Silt settles, making water clearer nutrient
  rich
• Trap filter water, Bacteria in soil break down
  contaminants
• Natures Septic Tank
• Natural chemical rxns neutralize and detoxify
  pollutants
• Gives H2O time to percolate (filter thru soil)
  replenish underground aquifers
• Threats- artificial eutrophication (see slide
  13), draining, sedimentation via construction

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Marine Ecosystems

• Benthic zone - lowest level. Organisms living in
  this zone are called benthos.
• Photic Zone well-lit upper layer of the oceans.
• Aphotic Zone - permanently dark layer of the
  oceans below the photic zone

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MARINE ECOSYSTEMS

• CORAL REEFS
• Clear, warm shallow seas
• Made up of accumulated calcareous (made of
  calcium) skeletons of coral animals
• Formation of reefs depends on light penetration.
• Corals have a symbiotic relationship with algae
  (which are photosynthetic) .
• Very diverse, abundant (Rainforests of Sea)
• Threats- destructive fishing (cyanide dynamite
  to stun fish), pet trade about 75 of coral
  reefs have been destroyed

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What factors can alter aquatic ecosystems?

• Natural Succession- normal cycle of pond becoming
  forest
• Artificial Succession- humans add Nitrogen
  Phosphate to water via fertilizer sewage
  causing succession to happen faster
  EUTROPHICATION

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What factors can alter aquatic ecosystems?

• Humans!
• Find food
• Recreation
• Waste disposal
• Cooling of power plants
• Transportation
• Dams, canals