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Patterns in Aquatic Ecosystems

Patterns in Aquatic Ecosystems. Shallow vs Deep Fresh vs Salt Swift vs Stagnant Changing vs Constant Ephemeral vs Permanent. Limnology vs Oceanography. Patterns of Aquatic Ecosystems. Important Properties of Water Types of Organisms Freshwater Ecosystems Marine Ecosystems

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Patterns in Aquatic Ecosystems

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  1. Patterns in Aquatic Ecosystems Shallow vs Deep Fresh vs Salt Swift vs Stagnant Changing vs Constant Ephemeral vs Permanent Limnology vs Oceanography

  2. Patterns of Aquatic Ecosystems • Important Properties of Water • Types of Organisms • Freshwater Ecosystems • Marine Ecosystems • Transition Areas

  3. Important Properties of Water • High specific heat • Warms and cools slowly • Large amount of heat necessary to raise temperature • Reaches max density at 4oC • Ice floats • Warm water above cold water

  4. Properties of Water • 800x more dense than air • Organisms still more dense • Need buoyancy

  5. Properties of Water • More viscous than air • More energy to move through water • Leads to streamlined shapes

  6. Properties of water… • Light attenuates quickly • Photosynthesis only in shallow waters

  7. Properties of Water • Phosphorus and Nitrogen limiting nutrients • Less oxygen than air • Enters at surface and via photosynthesis • Cold water holds more • Carbon dioxide and buffering

  8. Properties of Water • High surface tension • Can have organisms on surface

  9. Types of Organisms • Can classify based on mode of life/location • Can classify based on trophic mode

  10. Mode of life • Benthos - attached or resting on bottom • Epifauna: live on bottom (crabs, scallops) • Periphyton: attach to stems & leaves of rooted plants • Infauna: buried in sediment (clams, worms)

  11. Mode of life • Plankton • Floating, weak swimmers • Phytoplankton: photosynthesize • Zooplankton: herbivores & carnivores

  12. Mode of life • Nekton • Swimming organisms • Go where they want • Fish, squid, frogs, turtles, seals, octopus http://www.berkeley.edu/news/media/releases/2005/03/images/aculeatus_walk.mov

  13. Mode of life • Neuston • Rest or swim on surface

  14. Trophic Mode • Decomposers • Many insects, bacteria • Break down organic matter • Bacteria, fungi • Photsynthesizers (primary producers) • Derive energy from sunlight

  15. Trophic Mode • Deposit feeders • Eat organic material on bottom • Worms, some snails and clams • Filter feeders • Remove food from water • Clams, mussels, baleen whales…

  16. Trophic Mode • Grazers • Eat living plant material • Insects, sea urchins.. • Carnivores • Eat animals

  17. Types of Aquatic Ecosystems • Freshwater • Marine • Transitions between land & sea

  18. Freshwater Ecosystems • Lentic • Standing water • Lakes, ponds, bogs • Lotic • Running water • Streams, rivers

  19. Lentic Zonation • Limnetic: to depth of light penetration • Profundal zone: beyond depth of light penetration • Usually absent in ponds

  20. Lentic Zones • Littoral zone • Shallow, light penetrates to bottom • Rooted plants • High diversity • Subzones of vegetation • Emergent, floating, submergent

  21. Lentic Zonation • Limnetic zone • Depth of effective light penetration - compensation point • No benthos and few if any neuston

  22. Lentic Zonation • Profundal zone • Bottom and deep water region • Fewer plankton and no neuston • Absent in ponds

  23. Physical Factors • Transparency • Turbidity • Secchi Disk • Alkalinity (buffering capacity)

  24. Thermal Stratification • Epilimnion: warm surface water • Metalimnion: 0C changes with depth • Hypolimnion: cold deeper waters • Changes with season

  25. Thermal Stratification

  26. Seasonal Changes

  27. Stratification • Temperate lakes - mixed twice/year • Brings oxygen to bottom, nutrients to top • Tropical lakes • Low elevation: • Warm water on top, doesn’t cool regularly • Poor to no mixing • High elevation • Can stratify and mix daily

  28. Lake Productivity • Oligotrophic • Deep, sandy or gravel bottom • Low nutrients • low plant growth • low productivity • Low decomp at bottom • oxygen not depleted

  29. Lake Productivity • Eutrophic • Shallow, muddy, nutrient rich • High plant growth • high productivity • Summer stratifies • no mixing • Decomposition • depletes O2

  30. Oligotrophic vs Eutrophic

  31. Oligotrophic vs. Eutrophic

  32. Times of Low Oxygen Interesting • Dimictic vs. Meromictic lakes • Hypolimnion in the summer when no oxygen input • Productive lakes • Deep water fishery disappears • Heavy Snow Cover • No algal photosynthesis

  33. Dystrophic Kettlehole bog

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