Dissolved Gases
Warm Up
Turn to page 24 in your notebook.
Together we will complete the Rubber Duck activity and add it to this page.
Agenda
INB Setup
Dissolved Gases
Gas Exchange
Ocean Gas Exchange & Ecology
INB Setup
Turn to page 26 in your notebook and label it “Gas Exchange”
Turn to page 27 in your notebook and label it “Dissolved Gases”
Above the title on page 27 write the following:
GQ: What role do dissolved gases play in marine ecosystems?
Dissolved Gases
Ocean water holds dissolved gases.
How?
Pressure
Pressure can trap gases in liquids.
Ex: Soda, sparkling water
What does this mean for ocean zones of high pressure compared to zones of low pressure?
Deep water, which has a high pressure, holds more gas than shallow water.
Temperature
What happens to molecules when you add heat?
They speed up.
When you increase temperature of ocean water the gas molecules speed up and escape to the atmosphere.
Cold water holds more gas than warm water.
What gases are commonly found in ocean water?
Nitrogen
Nitrogen gas makes up ~78% of Earth’s atmosphere.
Waves disturb the ocean surface, stimulating the exchange of gases between the ocean and the atmosphere.
Oxygen
Oxygen makes up ~21% of Earth’s atmosphere.
Photosynthesis releases oxygen into ocean water which is in turn used by ocean organisms for respiration.
Carbon Dioxide
Carbon dioxide makes up ~0.04% of Earth’s atmosphere.
Animals release carbon dioxide as a byproduct of respiration.
Carbon dioxide is one of the most important gases that dissolve in the ocean.
Many marine organisms use the carbon dioxide to help form shells.
What About Salinity?
Salts are polar substances like water.
Nitrogen, oxygen, and carbon dioxide gases are not.
What does this mean?
Polar substances are strongly attracted to polar substances.
Seawater with low salinity holds more gas than high salinity water.
Ocean Gas Exchange & Ecology
Watch the following video, after watching we will have a brief discussion.
Things to consider while viewing:
Consider how an incredibly tiny organism can affect human populations.
Ocean Gas Exchange & Ecology
Discussion questions:
What organism supplies 50% of all oxygen breathed on Earth?
What connections can you make between ocean zones, currents, and dissolved gases? Look back at your notes.
How has global warming affected sea life?
Gas Exchange
Recreate the diagram below in your notebook on page 26.