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 4 o C –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/20 05/03/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: 0 C changes with depth Hypolimnion: cold deeper waters Changes with season

25. Thermal Stratification

27. Seasonal Changes

28. 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

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

30. Lake Productivity Eutrophic –Shallow, muddy, nutrient rich –High plant growth high productivity –Summer stratifies no mixing –Decomposition depletes O 2

31. Oligotrophic vs Eutrophic

32. Oligotrophic vs. Eutrophic

33. 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

34. Dystrophic Kettlehole bog