1. Characteristics of Ocean Water

2. Oceanography covers physical properties of the ocean:
Dissolved materials: minerals and salts (salinity) and gases
Properties that change with depth: light, temperature and pressure
Motion: Waves, tides, currents

3. Waters Unique Properties…
-Found in 3 states of matter on our planet
-High heat capacity: ability of water to hold heat energy and regulate our climate
-Universal solvent: can dissolve more things than any other solvent

4. Unique Properties of water are due to
Hydrogen Bonding- attraction between water molecules because of the unequal charges of O & H
Charges on O and H help it dissolve things like salts
Attraction between water molecules- a lot of heat is needed to increase water temp and when water cools it release a lot of heat

5. Result of weathering of rocks on land carried by rivers to the ocean
Salinity
Result of weathering of rocks on land carried by rivers to the ocean
Materials from the earth’s interior
Hydrothermal vents
Volcanic eruptions

6. Oceans have an average salinity of 3.5% or 35 ppt (35 ‰)
Materials in Seawater
Oceans have an average salinity of 3.5% or 35 ppt (35 ‰)
ppt= parts per thousand
More than 70 elements in seawater but the main ones are..

7. Chloride
Sodium
Sulphate
Magnesium
Calcium
Potassium

9. Dissolved Gases Oxygen, carbon dioxide and nitrogen
Dissolve into the ocean from the atmosphere through wave action
Dissolve better in cold water
Animal life can change the chemistry of ocean gases

10. Around 500 m water runs out of oxygen
Bacteria and other animals are using it during decomposition and respiration
Animals in this region and lower have large gills, modified hemoglobin or are inactive

11. Pressure We are under 1 atmosphere (atm) of pressure on land
Water is heavier than air so every 10 m deep = 1 more atm of pressure

12. Animal Adaptations and Pressure
Ocean life has adapted to deep ocean and 1000x our pressure with lightweight skeletons, little musculature, and reduced metabolic, growth and reproductive rates.
Diving mammals have rib cages that collapse and expand in result to changing pressure

13. Water Depth vs Light
Photosynthetic organisms use light to make sugars.
Sunlit area (top 100 meters) contains 90% of marine life
Colors of penetrate thru water differently
Red light filters out first and blue light goes the furthest
Red animals are essentially invisible in deep waters

16. Energy in the Ocean
Ocean takes longer to heat and cool than land due to its specific heat
Water temp decreases with depth

17. Motion in the Ocean…Tides
Daily rise and fall of the ocean (high and low tide)
Range as small as 1 m & as high as 20m
Some areas have 1 or 2 high & low tides
Caused by gravitational pull of moon on our ocean basin

18. TIDES Tides rise (FLOOD) to produce a HIGH TIDE
Moon/
Sun
TIDES
Tides rise (FLOOD) to produce a HIGH TIDE
And fall (EBB) (LOW TIDE)

19. Therefore, there are two high tides on Earth at any one time
This side is pulled towards the Sun and/or Moon by gravitational attraction
This side bulges out because of inertia
Therefore, there are two high tides on Earth at any one time

20. Marine Life and Tides
Some marine life time their reproduction to the high or low tide cycle
Horseshoe crabs come ashore to mate on the night of a high tide in May
Eggs hatch 2 wks later on a high tide and are washed into the ocean

21. Motion in the Ocean…Waves
Winds produce waves as it blows across the ocean’s surface
When waves enter shallow water they drag along the ocean floor
The wave top is moving faster than the wave bottom so it topples forward
Specialty waves: rogue waves, tidal waves and tsunamis

22. At the shoreline

23. Surf - sequence of breaking waves
Swash - water sliding up beach
Backwash - water flowing back down beach to sea

24. Longshore drift Waves arrive at a coast at an angle (swash)
Backwash returns at 90 degrees
Sand is moved along the beach = longshore drift or longshore current

25. Coastal deposition Result of longshore drift and a lot of sediment
produces extensions of deposit from the shoreline

26. May grow across a bay (baymouth bar)
spit = curved extension
May grow across a bay (baymouth bar)
May link an island to the main land (tombolo)

27. Motion in the Ocean-Currents
Rivers of water moving through the ocean
Surface currents caused by major wind belts
Deflected by the Coriolis Effect
Important in moving marine life and nutrients around the oceans

29. Vertical Ocean Currents
Differences in temperature and salinity change the density of water.
This causes sinking and rising of water in the ocean
Ocean conveyor belt- convection current of water moving between the equator and poles in the oceans
Takes 1600 years to cycle