1. Do Now:
What are the major differences between freshwater and saltwater bodies? Are there any similarities?

2. Aim: How are FW and SW layers classified?

3. Vertical Stratification in Freshwater Biomes
FW layers delineated based on:
Temperature
Oxygen content
Nutrient level
Seasonal changes
Disturbances
Where will oxygen content and nutrient level be greatest?

4. Vertical Stratification Based on Temperature
Epilimnion is less dense, warmer, the uppermost, and thus most oxygenated.
Thermocline is line between the two layers, temperature shifts dramatically.
Hypolimnion is the lower, colder, and denser layer.

5. Chart & Pic: Stratification Layers

6. What is the difference between the two? And Why?
SPRING
SUMMER

7. Vertical Stratification Based on Organisms
1. Littoral zone: very shallow; at shoreline
Ample sunlight for plants & animals
End of this zone is defined as the depth at which rooted plants stop growing

8. Vertical Stratification Based on Organisms
2. Limnetic zone: surface of open water to the deepest area which sunlight can reach.
Organisms that are residents here are short-lived and rely on sunlight to carry out photosynthesis

9. Vertical Stratification Based on Organisms
3. Profundal zone: Water is too deep for sunlight to penetrate. (Aphotic)
Photosynthesizing plants & animals can’t exist here
4. Benthic zone: The deepest layer in a body of water
Low temps
Low oxygen

11. Vertical Stratification in FW Biomes
Littoral zone
Limnetic zone
Profundal zone
Benthic zone

12. Pause…Write
We just learned about the stratification of layers in a freshwater system. Will the layers be the same for a salt water system? Explain your answer in complete sentences.

13. FW Oceans zones

15. SW Oceans zones 1. Coastal zone area closest to land
defined as shore to end of continental shelf

16. SW Oceans zones 2. Euphotic zone the photic, upper layers of water
warmest region of ocean water
highest level of dissolved oxygen.

17. SW Oceans zones 3. Bathyal Zone colder, middle region
receives insufficient light for photosynthesis

18. SW Oceans zones 4. Abyssal zone Deepest region Extreme cold temps.
Low levels of dissolved oxygen
High levels of nutrients sinking to bottom from zones above
Ex: detritus, decomposed plant and animal material
High pressure

19. Pic: SW Ocean Zones