Download Ch 20 Ocean Water Notes

Ocean Water
Chapter 20
Properties of Ocean Water
• Dissolved Gases: gases can enter the ocean
from streams, volcanoes, organisms, and
the atmosphere.
• Gases dissolve more rapidly in cold water
than in warm water.
• The oceans are a “carbon sink.”
Properties of Ocean Water
• Dissolved Solids: Ocean water is 96.5% pure
water (H20). 3.5% are dissolved solids called
sea salts.
• Most common solids (85%) are the salt halite
made up of sodium and chloride ions.
• Most of the sea salts come from chemical
weathering of rocks on land.
Salts in the Ocean
Salinity of Ocean Water
• Salinity: a measure of the amount of
dissolved salts in a given amount of liquid.
• Temperature affects salinity conditions.
Warm/Tropical regions have higher rates of
evaporation therefore have a higher
concentration of salinity (meaning more
salts).
Temperature of Ocean Water
• Pack Ice: a floating layer of sea ice that
completely covers an area of the ocean
surface. Ocean water freezes at about -1.9 C.
• Thermocline: a layer in a body of water in
which water temperature drops with increased
depth faster than it does in other layers.
Temperature of Ocean Water
Density of Ocean Water
• Density: the ratio of the mass of a substance
to the volume of the substance.
• Ocean water becomes denser as it becomes
colder and less dense as it becomes warmer.
The densest ocean water is found at the polar
regions causing it to sink.
Color of Ocean Water
• Water absorbs most of the wavelengths or
colors of visible light. Only blue wavelengths
tend to be reflected causing the ocean waters
to appear blue.
Life in the Oceans
• Marine organisms depend on 2 major factors
for their survival: essential nutrients available
in ocean water and sunlight.
• Marine organisms help maintain the chemical
balance of ocean water. They do this by
removing nutrients and gases from the water
while returning others to the ocean.
Upwelling
• Upwelling: the movement of deep, cold, and
nutrient-rich water to the surface. Upwelling
is caused by offshore movement of surface
water.
Life in the Oceans
• Most marine organisms live in the upper
100m of water.
• Plankton: the mass of mostly microscopic
organisms that float or drift freely in the
waters of aquatic environments. They live
within the sunlit zone and form the base of
most food webs in the ocean.
Life in the Oceans
• Nekton: all organisms
that swim actively in
open water, independent
of currents.
• Benthos: organisms that
live at the bottom of
oceans or bodies of fresh
water.
Ocean Environments
• Benthic Zone: the bottom region of oceans
and bodies of fresh water.
• Pelagic Zone: the region of an ocean or
body of fresh water above the benthic
zone.
Ocean Environments