Transcript Lec #3 - University of San Diego Home Pages

Water
• Properties
– Surface Tension
– Viscosity
– Changes in State
Temperature
• Most important factor governing life processes and the distribution of
organisms
• High Specific heat of water allows it to absorb or lose lots of heat
without changing temperature much
Temperature
• SST (Sea Surface Temperature) varies with latitude and
ranges between -1.9 º - 40 º C
Temperature
• Surface Mixed Layer (Redish Color): water layer of almost uniform
temperature caused by mixing from wind and waves
• Thermocline (Green): area where temperature changes rapidly with
depth
• Deep Ocean (Blue): gradual temperature change (water temp between
0 - 4 º C)
Temperature
• Depth profile of temperature from South to North in Atlantic Ocean
Temperature
• SST can be used to designate biogeographic zones
• Organisms adapted to specific temp ranges
– Ectotherm
– Endotherm
Salinity
• Weight (grams) of inorganic salts dissolved in 1 kg of
water
– Units are ‰ or psu (Practical Salinity Units)
Salinity
• Where do Salts come from?
Salinity
Salinity
• What impacts salinity in the oceans?
• Ocean Salinity ranges between 32 - 38 psu (34.7 psu
average)
Salinity
Salinity Profile of the Atlantic Ocean
Salinity
• Why do we care about salinity as biologists?
– Salinity will impact the salt content inside organisms
bodies
– Affects the buoyancy of pelagic organisms
– Partly impacts the density of water
Salinity
Diffusion: molecules tend to migrate away from regions of higher
concentrations to areas of lower concentrations
Salinity
Osmosis: movement of water across a selectively permeable
membrane from areas of low salt content to areas of
high salt content
• Osmoconformer
• Osmoregulator
Salinity