ocean chemistry goal: describe salinity and factors that are affected by changes in salinity levels....
TRANSCRIPT
Ocean Water Chemistry
Ocean ChemistryGoal:Describe salinity and factors that are affected by changes in salinity levels.
Agenda:1. Wrap up ‘Ocean Profile’ lab2. Warm-up for Chemistry3. Salinity Reading4. Demo./Notes
Warm-upHow is salt added to the ocean?
The Water CycleLife could not exist without the water cycleThe water cycle continuously moves water
between the atmosphere, the land, and the oceans.
The Water CycleWater vapor condenses and falls to the
Earth’s surface as precipitationSome of this water percolates into the soil to
become ground waterSome runs across the surface into lakes,
rivers, and the oceanThe water is heated by the sun and reenters
the atmosphere by evaporation
Precipitation
Evaporation
Condensation
Evaporation
Percolation
Characteristics of Ocean WaterOcean water is
salty!
The salt is called Sodium chlorideWhy???
SalinityThe amount of dissolved
solids in a given amount of liquid is called salinity
Measured in ppt (parts per thousand)
For example: 1000 grams of ocean water can be evaporated and leave 35 grams of solids behind
How did the oceans get salty?Water flows from land into the oceans and
brings minerals as it flows over rocks and slowly wears them down
At the same time, water is evaporating and leaving the minerals behind
Stop and Think Describe three factors that influence salinity and their relationships.
Factors Affecting Salinity: ClimateCoastal waters in places with hotter, drier
climates typically have higher salinity.Why?
Higher rate of EVAPORATION Removes water but leaves salt behind
Coastal waters in cooler, more humid places typically have a lower salinityLower rate of evaporation
Evaporation = Salinity
Evaporation = Salinity
Factors Affecting Salinity: River runoffCoastal waters near an emptying river tend
to have lower salinityWhy?
The freshwater dilutes the saltwater
Coastal waters not near an emptying river tend to have higher salinity
Fresh water = Salinity
Fresh water = Salinity
Factors Affecting Salinity: MovementSome parts of the ocean move less than other
partsBays, gulfs, seas, open ocean where there’s no
currentSlower moving areas of water develop higher
salinity Less circulation (no currents running through them)
so salt settles here
Faster moving areas of water develop lower salinity
Movement = Salinity
Movement = Salinity
Warm-upExchange paragraphs with a partner and discuss the answers.
Temperature ZonesThe temperature of ocean water decreases as
depth increasesThis change is NOT gradualWater in the ocean can be divided into three
layers by temperature Water at the surface is much warmer than
the average water temperature
Ocean Temperature ZonesSurface Zone
Thermocline
Deep Zone
• Warm, mixed by waves—aka “mixed zone”
• Sunlight, plant growth• Temp depends on latitude
• Temperature drops rapidly with depth
• Uniformly cold• 1-3 degrees C• Polar creep—ocean current
Warm-upHow do thermocline graphs differ depending on latitude and seasons? Describe different latitudes and seasons.