Properties of water South High Marine Biology

1. Properties of waterSouth High Marine Biology

2. Water molecules • 2 Hydrogen atoms bonded to 1 Oxygen atom covalently at a distance of 105° • Results in a slight charge on each end of the molecule making water “polar” Oxygen orients to Hydrogen end to end with “weak” Hydrogen bonds • This creates properties of cohesion,adhesion, & surface tension

3. Cohesion( a function of polarity) A physical property of water “sticking” to itself. Weak Hydrogen bonds attaching + charged Hydrogen to - charged Oxygen(called polar bonds) --creates “surface tension.” --Results in lower evaporation rate -- capillary action

4. adhesion • The physical property of water “sticking” to other things. • This is also a result of its “polar” properties. -- capillarity -- things stay “wet” longer (Intertidal organisms)

5. Surface tension • A property of cohesion; • the tendency of a liquid surface to for a “skin” owing to the bonding forces between molecules. • Quieting force for waves less than 2 feet (gravity is the other)

6. Latent heat of fusion/vaporization • Heat is required to cause a change of state without causing a rise in temperature. • 80 Calories per gram of ice must be removed to cause a change of state. • Lakes don’t freeze or thaw quickly because of heat loss/gain required to cause change

7. Change of state Solid,liquid,gas • Addition of energy (heat calories) causes changes in state from solid to liquid to gas. • Evaporation is a cooling process • Condensation releases heat • Sublimation--solid to gas, skipping the liquid phase. • Dew point: temp which water condenses

8. Heat capacity akaheat index • Amount of heat a substance absorbs per gram • Very high for water • Oceans don’t freeze readily, and don’t warm significantly • Allows for a narrow temp range for organisms

9. Density • Fresh water=1.0g/cm3 @4°C • Salt water = 1.0278 g/cm3 • Ice = 0.917g/cm3 • Density increases as temp decreases, salinity increases, & pressure increases. • Density helps drive circulation of ocean waters. • Living organisms tropical(less dense) waters evolved frilly appendages to assist in floatation

10. compressability • Nearly incompressible • 1 atm = 14lbs per in 2 • Pressure increases 1atm for every 10m of depth • Sea levels would be 121 ft higher if water was noncompressible • Some organisms have adapted to extreme pressures that would kill others

11. viscosity • Property of fluid to resist flow, the higher the viscosity, the thicker the fluid • Increase in water temp, increases viscosity • Addition of salt increases viscosity • Microorganism float easier. Some develop appendages to increase ability to float

12. Light • Seawater transmits the visible spectrum only • 60% light energy absorbed in the first meter, • 80% by 10 meters. • 1% of light appears in clear water below 150 meters • no light below 1000m • Blue-green light is absorbed by clear water.

13. Attenuation: transparency of water • The order in which wavelengths of light are absorbed by water. • determines to what depths plants may grow • Attenuation is influenceds by silt, plankton,and salts

14. Light refraction in water • The speed of light slows down when it strikes water creating refraction.

15. Energy transmissionConduction, Convection, Radiation • Conduction: heat applied in one location, molecules speed up and warm a specific area. • Convection:Heat is carried to a new location • Radiation: Heat is transferred directly from its source

16. Sound in water • Sound travels faster& farther in water than air • Velocity is 1500m/sec • Temp, pressure, salt content, increase speed • Water dissipates high frequency sound faster than low frequency • These properties allow long range communication • Echolocation allows animals to find prey, calculate distances & shapes

17. SoFar Channel • A channel that runs horizontally through the water from 500 feet to 1500 feet. Sound is reflected to stay within the Sofar channel. • Animals communicate over long distances.

18. Sea steady state • Salinity of the oceans stays constant over time. • Salt into the system is balanced by salt leaving the system via precipitation.

19. Solubility of gases • Gases interact at the surface, and dissolve at all depths • Nitrogen and Co2 are most abundant • Mixing by current and wave movement • Oxygen levels decrease with depth as organisms use it up & no plants in the photic zone to produce more.

20. Salinity • The total quantity of dissolved salt in seawater. • Average is 35gNaCl/kg of H2O • Salinity changes with latitude, equator and middle lats are saltier than rainy areas. • Depth salinities are slight

21. Effects of salt • Increases density. Salt content average is 35g/kg; • At 24.7g/kg or less, salt water acts like fresh water • Salinity lowers the freezing point to -1.332°C • Salts are incorporated by living organisms to make shells.

22. Sea ice • Ocean water freezes at -1.4°C • Pancake ice forms first, evolves into sea ice by wind, temp, currents driving ice together and solidifying it • Pressure ridges may be formed by collision of sea ice plates • Little to no light reaches underwater

23. Green Icebergs • Algae & plankton grow on the underside of an iceberg. • The berg becomes too top heavy and turns upside down exposing the algae. • Antarctic bergs exhibit this phenomenon

24. Icebergs • 12% of their mass is above the surface • Castle bergs-irregular shape. • Tabular bergs- flat topped, large, originate off of ice sheets • Their movement shows current paths

25. Fog; advective, • Advective fog most common. Forms when warm air saturated with water moves over cold water, condensation occurs • Sea smoke: dry cold air from the land moves over warm water • Radiative fog: moist air at night condenses over land, forms thick layer, quickly gone with the sun

26. Sea smoke • Fog caused by dry, cold air moving over warm water. The water warms the air above it, which picks up water vapor. The vapor rises and cools;this causes condensing and fog

27. Sound shadow zones

28. Dissolved salts and ions • 6 major ions make up over 99% of the dissolved ions in seawater • Over 30% of ions are Sodium & Chlorine. Positive ions are cations; negative ions are anions • Silicon ions are essential for life processes of many organisms • Ions from hydrothermal vents are available to organisms in the deep oceans