Unique Nature of Pure Water
What two elements make up a water molecule?
Hydrogen and oxygen
What is the amount of dissolved salt in water called?
Salinity
What is the main dissolved substance that makes seawater salty?
Salts
What gas is mainly responsible for ocean acidification?
Carbon dioxide
What is the ocean's sunlit upper layer called?
Photic zone
What is the chemical formula for water?
H₂O
What is the average salinity of seawater?
About 35 parts per thousand (35%)
Which gas dissolved in seawater do marine animals need for respiration?
Oxygen
What process removes carbon dioxide from the atmosphere using sunlight?
Photosynthesis
What is the name of the zone where little or no sunlight reaches?
Aphotic zone
What is the attraction between water molecules called?
Hydrogen bonding
What happens to seawater density when salinity increases?
Density increases.
What is the most abundant dissolved salt in seawater? Sodium chloride
Sodium Chloride
What happens when carbon dioxide dissolves in seawater?
It forms carbonic acid
What is the transition layer where temperature decreases rapidly with depth?
Thermocline
What is the difference between temperature and heat?
Temperature measures average kinetic energy; heat is total
What three factors affect seawater density?
Temperature, salinity, and pressure
What is the pH scale used to measure?
How acidic or basic a substance is
How does ocean acidification affect organisms that build shells?
It makes it harder for them to build and maintain shells.
Why does photosynthesis mainly occur in the photic zone?
It receives enough sunlight for photosynthesis.
Why does water require a lot of energy to change temperature?
Hydrogen bonds absorb energy before breaking.
Why does cold seawater generally sink below warm seawater?
Cold seawater is denser.
Why are dissolved gases important to marine organisms?
They support processes such as respiration and photosynthesis.
Explain how burning fossil fuels can affect ocean chemistry.
It increases atmospheric CO₂, causing more CO₂ to enter the ocean and lower its pH.
How do temperature and sunlight generally change as you travel deeper into the ocean?
Both generally decrease