Properties of Seawater

What do you see?

The Blue Planet

What makes water so special?

• High heat capacity

• High latent heat of vaporization

• High latent heat of fusion

• Density of solid less than density of liquid

• Dissolving power

What makes the oceans so special?

• 70% of Earth covered by water

• But…

Location Percent

Ocean 97%

Ice 2%

Ground Water, Lakes/Rivers, Atmosphere

1%

What is seawater made of?• The ocean is one big solution• Dissolved solids (Na, Cl, Mg, Ca, S)• Dissolved

gases (CO2,

O2)

World Ocean Salinity

• Average salt by volume 3.5%

• Salinity reported in Practical Salinity Units (PSU) or parts per thousand ‰

• Salinity of 3.5% ≈ 35 PSU ≈ 35 ‰

• Monterey Bay ≈ 33.5 ‰

• San Francisco Bay varies from 0 - 35 ‰ depending on location

Surface Salinity MapThe saltiest water is found in areas colored RED (Mediterranean Sea)

The least salty water is found in areas colored BLUE (the north pole)

Density of Seawater• D=m/v (g/cm3)• Density of seawater depends on

– Salinity-- more salt = more mass• Higher density

– Temperature— colder water = less volume• Higher density

– Depth-- higher pressure = less volume• Higher density

• Density influences ocean circulation below the surface

Most Humans Float in the Dead Sea

• Dead Sea

• 290 ‰ salt

• 1.17 g/mL density

• Humans

• 9 ‰ salt (blood)

• 1.1 g/mL density

Seawater & Global Warming

• What would happen to the SOLIDS dissolved in seawater as the water warms due to global warming?A. More of them would dissolve

B. Less of them would dissolve

C. There would be no change

Seawater & Global Warming

• What would happen to the SOLIDS dissolved in seawater as the water warms due to global warming?

A. More of them would dissolveB. Less of them would dissolve

C. There would be no change

Seawater & Global Warming

• What would happen to the GASES dissolved in seawater as the water warms due to global warming?A. More of them would dissolve

B. Less of them would dissolve

C. There would be no change

Seawater & Global Warming

• What would happen to the GASES dissolved in seawater as the water warms due to global warming?A. More of them would dissolve

B. Less of them would dissolveC. There would be no change

Seawater & Global Warming

So what does that mean?

increasing the temperature of the atmosphere (global warming) changes how solids and gases can dissolve in the ocean

Seawater & Global Warming

So what does that mean?

global warming is changing the chemistry of our oceans!

changing the chemistry of our ocean affects marine life, and ultimately YOU

So, how does the ocean affect you?

Raise your hand if any of the following statements are true for you.

• I eat fish/ seafood regularly

• I eat ice cream regularly

• I drink chocolate milk

• I wash my hair with shampoo

Seawater & Global Warming

• If you raised your hand, you use a product that comes from the ocean. That means that changes in the ocean can affect you!