1. Chemical and Physical Properties of Seawater
Chapter 3, p

2. Specifics Properties of water Ocean Circulation Waves and Tides
Brainstorm with a partner!

3. Unique properties of water
All 3 states of matter on Earth
Very polar molecule
Weak hydrogen bonds

4. Evaporation
Liquid  Gas
Hydrogen bonds broken
Density and temperature

5. Temperate and State Less dense as a solid than a liquid.
Habitat and insulation for organisms
H+ bonds result in higher melting and freezing temp.

6. Latent heat of melting
Latent heat of melting – the amount of heat required to melt a substance
Absorbs A LOT of heat when it melts –
Hydrogen bonds break, but motion of molecules does not speed up until all of the ice melts.
It takes A LOT of energy to break hydrogen bonds!

7. Heat Capacity
Water is able to absorb a lot of heat with a relatively small increase in temperature
HIGH heat capacity – amount of heat needed to raise a substance’s temperature by a given amount
Important for marine organisms
Not exposed to rapid changes in temperatures

8. Latent heat of evaporation
One of highest of all substances on Earth
Only fastest moving molecules can break hydrogen bonds and evaporate
Molecules left behind in the liquid phase have a lower temperature – evaporative cooling

9. Water Cycle

10. Properties of Seawater
Water is the universal solvent
Ion dissociation

11. Seawater Salinity – total amount of salt dissolved in seawater
Not just Na+ and Cl-
Lots of salts!
See p. 48, Table 3.1
Where do the salts come from?
4nd period

12. Where might ion concentrations of seawater differ from the normal amounts?

14. Salinity, Temperature, Density
More salty = More dense
Lower temperature  more dense
Measuring temperature and salinity at specific points in the ocean – Niskin bottles
Let’s take a look!

15. Temperature Profile
Temperature and salinity at several depths at once; above is a temperature profile or thermocline (zone of rapid temperature change).
7th period

16. SST Satellite Images
Current Conditions

17. Temperature and Salinity
4th

18. SST of NE coast of the United States. Do you know the current?

19. Dissolved Gases Oxygen (O2) – not very soluble
Most released through photosynthesis
Amounts also dependent upon respiration
Carbon Dioxide (CO2) – more soluble
80% of dissolved CO2 is in ocean
Nitrogen (N2)
Dissolve at surface of water or gases released into air
Gas dissolves best in cold water

20. Oxygen Content of Ocean
High oxygen content near the sea surface
Low oxygen at mid-depth
Increase in oxygen in the water ~ 1 km water below sea level

21. CO2 in the Ocean
How is the fact that 80% of the world’s CO2 is found in the ocean affecting our oceans?

22. CO2 Emissions
CO2 is much more soluble than oxygen because it reacts chemically when it dissolves
CO2 makes up more than 80% of the dissolved gas in the ocean, compared to less than 0.04% of air
Ocean stores more than 50x as much total CO2 as the atmosphere.

23. Light Conditions CO2 + H2O + sun energy  C6H12O6 + O2
C6H12O6 + O2  CO2 + H2O + energy
Must have the right light conditions to fuel photosynthesis!
Light levels change with depth.
7th

24. Visible Light Spectrum

25. Colors of the Ocean
7th
Photos courtesy of www. science.nasa.gov

26. Depth of 30 m: Only blue light remains:
Under natural lighting this sea star appears light blue, with the tips of the arms almost black.
A flash reveals the sea star’s true colors.

27. Light Zones
1. Photic zone – sunlit, 200 meters below the surface of the ocean
2. Twilight zone - from about meters below the surface.
3. Abyssal zone – no sunlight, from meters below the surface to the bottom of the ocean.

28. Light Penetration of Surface Waters

29. Gathering Data
4th

30. Pressure in the Ocean
Organisms on land are under 1 atm (14.7 lbs/sq in or psi) at sea level. The weight of all the air above them.
Marine organisms are under the weight of water as well as the atmosphere.
Since water is much heavier than air, marine organisms are under much more pressure than those on land.
As the pressure increases, gases are compressed. Gas-filled structures inside organisms like air bladders, floats, and lungs shrink or collapse.
Limits depth range of organisms
We need special equipment to go deep or special instruments that can withstand pressure

31. Pressure in the Ocean

32. Ocean Circulation
Currents move ocean waters around the world’s oceans at different depths
Currents circulate heat, nutrients, pollution, and organisms
Great affects on earth’s climate
New Gulf Current

33. The Coriolis Effect
If the Earth did not rotate on its axis, the atmosphere would only circulate back and forth between the poles and the equator

34. The Coriolis Effect
Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. This deflection is called the Coriolis effect.

35. Wind Patterns
Winds in atmosphere are driven by heat energy from the sun.
Equator is warmer than poles – more heat energy absorbed here
Less dense hot air rises
Cooler air replaces it
Wind is formed!
Remember, winds to not travel straight, they are bent by Coriolis Effect

36. Trade Winds
30°N
Doldrums
30°S
Air near equator is warmed by solar heating and rises. Air from higher latitudes moves in over the Earth’s surface to replace the rising air, creating winds. The TRADE WINDS are deflected by the Corliolis effect and approach the Equator at an angle of about 45°.

37. Ekman Transport
If the ocean current is regarded as layered, then each deeper layer moves more slowly than the overlying layer.

38. How do the continents effect the wind patterns?
Global Wind Patterns
The major wind patterns are created by the rising of sun-warmed air and the sinking of cold air.
How do the continents effect the wind patterns?

39. Major Surface Currents

40. Ocean Gyres Created by wind-driven surface currents
Moderate climate by bringing warm water north and cold water south

41. Thermoclines Depth profiles for salinity, temperature, and density
What is a thermocline and how does it develop?
Seasonal vs. permanent thermoclines

42. Temperature Profile
Stable water column = less dense shallow and more dense deeper
Unstable water column = surface water sink and mixes with deeper water
DOWNWELLING
Polar regions in winter

43. Ocean Mixing
These two water masses originate at the surface in the extreme North and South Atlantic, then sink and spread along the bottom.

44. Thermohaline Circulation
The movement (circulation) of water in the ocean over great distances that is driven by changes in density
Changes in density determined by temperature and salinity.
“Fingerprint” of the water mass is how currents are tracked

45. Circulation of the Ocean
The Great Ocean Conveyor – Global current pattern Deep circulation of the oceans is part of the global pattern known as great ocean conveyor. This constantly replenishes the oxygen supply to the depths.

46. Waves
Water particles do not move along with a wave but instead move in circles. When under the crest they move up and forward with the wave, then they are pulled back down. As wave after wave passes, the water and anything floating in or on it moves in circles.

47. Waves Fetch - the span of open water over which the wind blows
Fetch is important in determining the size of waves
Wind starts the wave which eventually settles out into a swell as it gets farther from the source of wind.

48. What kind of waves are these?

49. Waves
Storm winds generate seas, peaked with waves with relatively flat troughs.
When the waves reach shallow water, they get higher and shorter (closer together). They become unstable and break, expending their energy on the shoreline.
Water particles under swells have the ideal circular motion.
In shallower water the influence of the bottom causes the particle motion to flatten out into a back and forth movement known as surge

50. Tides
Gravitational pull of the moon and sun and by the rotations of the earth, moon, and sun.
The moon and earth are held together by gravitational attraction. The moon’s gravity is strongest on the side of the earth closest to the moon.
Centrifugal force produced by the earth’s motion causes water to bulge outward, away from the moon.
On the side of the earth closest to the moon, the gravitational pull overcomes the centrifugal force and pulls the water into a bulge toward the moon.

51. How does a grunion (Leuresthes tenuis) use the tide?

52. Tides
Because the moon moves while the earth is rotating, a full tidal cycle takes 50 minutes longer than the 24 hrs it takes the earth to make a complete rotation.

53. Tides
1. Spring Tide - The tidal bulges are largest, and therefore the tidal range is greatest, when the moon and sun are in line - new and full moon.
2. Neap Tide - Tidal ranges smallest when moon and sun are puling at right angles, which occurs when the moon is in quarter.

54. Tides Semidiurnal tides – 2 high tides and 2 low tide per day
Bay of Fundy
How tides work: great demo

55. Tides
Worldwide distribution of semidurinal (2H, 2L), mixed semidiurnal (2H and 2L of different heights), and diurnal (1H, 1L) tides.