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