1. Lesson 3: More about water

2. Thinking – 97% of earth’s water is salty………
Where does the salt in the ocean come from? __________________________________________________
Does the ocean have the same “saltiness” everywhere? Why or why not? Do you have any evidence to support your answer? (i.e. – visits, readings)
________________________________________________________________ ________________________________________________________________
How might salt affect marine organisms? ______________________________________________________________

3. Thinking – 97% of earth’s water is salty………
Where does the salt in the ocean come from?
Minerals, rivers, sediments
Does the ocean have the same “saltiness” everywhere? Why or why not? Do you have any evidence to support your answer? (i.e. – visits, readings)
Yes, depends on the volume of the body of water as well as temperature which leads to evaporation.
How might salt affect marine organisms? They have to adapt to ranging saltiness, most organism prefer 0.9% saltiness for homeostasis.

4. Water: the universal solvent
Water’s unequal distribution of electrons gives it extreme solubility
This is called polarity
Many salts in the ocean easily dissolve in water
Salts typically contain a metal and nonmetal
Creates an ionic bond which is a transfer of electrons
Let’s draw an ionic compound:
Na – atomic number?
Cl – atomic number? 11 17

5. When water interacts with salt, the NaCl ionizes meaning it splits into individual ions
This is what happens when a substance dissolves.
Na+ is attracted to the negative side of water
Cl- is attracted to the positive side of water

7. Properties of compounds and molecules
Conductivity – ability of a substance to carry an electric charge
Created by dissolved salts
Pure or distilled water has no ions therefore does not conduct electricity

8. Properties of compounds and molecules
Salinity – measure of dissolved salts in water
Seawater contains sulfate, magnesium, calcium, potassium, and bicarbonate in addition to sodium chloride
Average salinity = 35 ppt (3.5%)

9. Properties of compounds and molecules
Distilled water has no salinity
Fresh and tap water have very low salinity
Water is considered fresh if < 1 ppt salt
Expressed in practical salinity units or PSU.
1 PSU = 1 ppt

10. Global map of sea surface salinity

11. Organize your data Type of Water Average Salinity (PSU Distilled Tap
Fresh
Salt

12. Organize your data Type of Water Average Salinity (PSU) Distilled Tap
Tap
0.5
Fresh 1
Salt 35

13. Why is the sea salty?
Water’s excellent ability to act as a solvent carries materials all over Earth. Similarly, the water in your blood helps carry oxygen, vitamins, minerals, and nutrients to your body’s cells.

14. Where does it come from? From Land:
4 billion tons of salt are carried by rivers into oceans each year

15. Hydrothermal vent at seafloor
From inside the Earth:
Volcanoes, hydrothermal vents, and other processes at seafloor spew minerals from Earth’s crust into ocean
Hydrothermal vent at seafloor

16. Particles deposited by wind
From the Atmosphere:
Particles carried by wind are deposited into ocean
Both natural and human-made

17. Salinity and marine organisms
Brackish – water that is somewhere between salty and fresh
Estuaries – where rivers meet the sea
Mangrove forests and salt marshes
“Nurseries of the sea”
Young organisms develop here
Prevent erosion

18. NOAA estuary Videos Based on the videos:
North Carolina Estuaries
Southwest Florida Estuary
Based on the videos:
Describe 3 important roles of estuaries ____________________________________________________________________ ____________________________________________________________________
Based on what you know about density from the last Lesson, describe how the fresh water and salt water in an estuary would form layers ____________________________________________________________________ ____________________________________________________________________

19. NOAA estuary Videos Describe 3 important roles of estuaries.
Provide a habitat for commercial and recreational fish
Protect coastlines
Filter pollutants from the water
Serve as a resting place for migratory birds
Provide a habitat for juvenile fish, seabirds, and shellfish

20. NOAA videos
Based on what you know about density from the last Lesson, describe how the fresh water and salt water in an estuary would form layers.
Fresh water from the river will lay atop the salt water because fresh water is less dense.

21. Osmoregulation: a balance act
Why do you are fingers looks wrinkled after swimming or being in the bath too long?
_______________________________________________________________
Actually they are swelling!!
Liquid in your cells has a higher salinity than the fresh water surrounded them.
Osmosis occurs – do you recall?
Movement of water from high to low concentration
Challenge: Is this hypotonic or hypertonic?
Hypotonic!!!

22. Because of the process of osmosis, many bony fish in the ocean lose water to their highly saline environment. In order to stay hydrated, they drink a lot of seawater and secrete the salts through specialized cells and excrete concentrated urine.

23. Freshwater fish experience the opposite problem
Freshwater fish experience the opposite problem. If it was not for osmoregulation, their cells would be constantly taking on water, like your skin cells in the bath. Instead, freshwater fish produce a lot of dilute urine, which gets rid of excess water in their systems.

24. Lab 2: Investigating surface tension

25. cohesion
Recall from Bio I: Water is “stickiness” due to hydrogen bonding.
Leads to surface tension.

26. cohesion

27. Surface tension

28. Astronaut Leroy Chiao watches a water bubble float between him and the camera on the International Space Station. Materials onboard are exposed to microgravity, allowing the properties of water to be understood more clearly.

29. Water droplet on a leaf onboard the International Space Station
Water droplet on a leaf onboard the International Space Station. The spherical nature of water is shown in an environment with virtually no gravity.

30. Mangrove trees in the U. S. Virgin Islands showing off their roots
Mangrove trees in the U.S. Virgin Islands showing off their roots. Water's property of cohesion allows materials to be distributed through the bodies of living things like plants and animals.

31. Sponges, such as this large one with a Rock Hind hiding inside, are filter feeders. They pump water in through their pores and remove food particles.

32. evaluate
List the following types of water in order of increasing salinity:
Brackish water
Distilled water
Salt Water
Fresh Water

33. Distilled water
Fresh water
Brackish water
Salt water

34. Explain how the chemical structure is related to:
A. Cohesion
B. Salinity

35. Give 2 examples of how marine organisms are affected by the properties of water such as density, ability to exist in all 3 states of matter, ability to dissolve materials, high heat capacity, and cohesion.

36. The Hudson River borders New York and New Jersey and is an interesting study in salinity. The river begins high in the mountains of New York State and runs fresh for hundreds of miles, even as far south as Manhattan during spring rainstorms and snowmelt. Salty water from the Atlantic Ocean pushes upriver due to the tides. During drought conditions when fresh water is scarce, salt water extends as far north as Poughkeepsie.