Properties of Ocean Water & the Ocean Floor

Water density Maximum density at 4oC Ice less dense than liquid water Atomic structure of ice Ice floats Increased salinity decreases temperature of maximum density

Seawater Salinity=total amount of solid material dissolved in water (g/1000g) Typical salinity is 3.5% or 35 o/oo or ppt Brackish (hyposaline) < 33 ppt Hypersaline > 38 ppt

Dissolved Gases in the Ocean O2 high in surface ocean due to photosynthesis O2 low below photic zone because of decomposition O2 high in deep ocean because source is polar (very cold) ocean CO2 low in surface ocean due to photosynthesis CO2 higher below photic zone because of decomposition Deeper seawater high CO2 due to source region and decomposition

Surface variations of salinity Polar regions: salinity is lower, lots of rain/snow and runoff Mid-latitudes: salinity is high, high rate of evaporation Equator: salinity is lower, lots of rain Thus, salinity at surface varies primarily with latitude

Vertical variations of salinity Surface ocean salinity is variable Deeper ocean salinity is nearly the same (polar source regions for deeper ocean water) Halocline, rapid change of salinity with depth

Imagine you were walking along the ocean floor. What would you see? What would you feel? What would you encounter?

Ocean Floor Contains the world’s largest mountain range (40,000 miles long) & canyons deeper than the Grand Canyon 2 Major Regions: Continental Margin: made of continental crust Deep-Ocean Basin: made of oceanic crust

Ocean Floor Continental Margin: Continental Shelf Continental Slope Continental Rise

Ocean Floor Deep-Ocean Basin: Abyssal Plain Mid-Ocean Ridges Rift Valley Ocean Trenches Seamounts

Ocean Floor Features