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Oyster Harvests in the Chesapeake Bay
A River
And an Ocean
What Is an Estuary?A meeting place between:
The Chesapeake Bay
• Largest of 130 estuaries in the U.S.
• 18,000,000,000,000 gallons of water
• 3600 species of plants and animals
• 500,000,000 pounds of seafood every year
The Chesapeake Bay
• A diverse habitat:Water
Marsh
Mud
When a River Meets the Sea, What Are the 2 Main Water
Properties that are Affected?–Temperature
–Salinity
Both of these affect the
DENSITY of the water
First, Let’s Look at Density
• What is DENSITY?• Density describes
how tightly packed the molecules in a substance are
• What would happen to the density if salt was added?
Adding salt ____________ the density of the solution.
INCREASES
When River Water and Ocean Water Meet
They may mix together
They may
form layers
They may do
some of both
What Will Happen if Salt Water is Added to Fresh Water?
• Will they mix together?
• Will they form layers?
• What is your prediction?
SALT FRESH
Salinity Plays an Important Role in Estuarine Circulation
As river water and ocean water meet, how do they interact?
River
Ocean
Salinity Plays an Important Role in Estuarine Circulation
The Chesapeake Bay is a partially mixed estuary.
River
Ocean
HOW IS SALINITY IMPORTANT TO WATER CIRCULATION IN
THE BAY?
FRESH
SALT
How Do We Measure Salinity?
• We can use a HYDROMETER to measure density
• Which cylinder contains the salt water?
• Remember, as salt is added to water, density will increase.
HYDROMETER
How Do We Measure Salinity?
• We can use the refraction of light to measure salinity.
• This works because light bends as it goes through different densities
• The saltier the water, the denser the water and the more the light bends
How to Use a Refractometer
These Water Samples Were Taken from Different Depths in the Bay, Can You Match the Depth with the Sample?
SAMPLE #1: 0 o/oo
SAMPLE #2: 35 o/oo
SAMPLE #3: 20 o/oo
Depth of water
sample
Salinity of water
sample
1 meter
(surface)
5 meters
10 meters
These Water Samples Were Taken from Different Depths in the Bay, Can You Match the Depth with the Sample?
Depth of water
sample
Salinity of water
sample
1 meter
(surface)
Sample 1:
0 o/oo
5 meters
10 meters
These Water Samples Were Taken from Different Depths in the Bay, Can You Match the Depth with the Sample?
Depth of water
sample
Salinity of water
sample
1 meter
(surface)
Sample 1:
0 o/oo
5 meters Sample 3:
20 o/oo
10 meters
These Water Samples Were Taken from Different Depths in the Bay, Can You Match the Depth with the Sample?
Depth of water
sample
Salinity of water
sample
1 meter
(surface)
Sample 1:
0 o/oo
5 meters Sample 3:
20 o/oo
10 meters Sample 2:
35 o/oo
What Happens to the Salinity
in the Chesapeake Bay as the Water Gets
Closer to the Ocean?
Can You Match the Water Sample to the Part of the Bay It Came From?
• 0 o/oo
• 15 o/oo
• 30 o/ooSite A
Site B
Site C
Can You Match the Water Sample to the Part of the Bay It Came From?
Site A0 0/oo
Site B15 0/oo
Site C30 0/oo
How Does Temperature Affect Density?
As temperature increases, the speed of the water molecules increases.
Does the density of the water increase or decrease as the molecules move faster?
How Does Temperature Affect Density?
As temperature INCREASES
density DECREASES
Think About a Hot Air Balloon!
• The air inside is warmer than the air outside, so the density is lower inside than outside
• So the balloon will rise to the top!
Can You Predict What Will Happen When Cold Water Is Added to Hot Water?
Make your prediction and then watch the demo.
Would the order that the water is added matter?
COLD HOT
In the Chesapeake Bay, Where Would You Expect Water to Be
Warmest?• At the top?
• Or at the bottom?
As the Seasons Change, the Temperatures of the Water Change
As the water warms up in summer time, will the water at the surface stay there or sink?
As the Seasons Change, the Temperatures of the Water Change
As the warm water begins to cool down in the Fall, will the water at the surface stay there or sink?
How Does Salinity Affect the Organisms that Live in the
Chesapeake Bay?
• Cut out the 6 Chesapeake Bay Organisms
• Paste each on the map of the Chesapeake Bay where they can find the salinity level needed to survive.
CROAKER
ANCHOVYBLUE CRAB
SILVERSIDE
SEATROUT
SHAD
Why Are Temperature and Salinity Important to the Different Organisms in the Chesapeake Bay?
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http://mysterycargo.infofor more adventures
