Physical Properties of Seawater
What percentage of seawater is made up of water molecules?
96.5%
What is the average salinity of seawater in parts per thousand (ppt)?
35 ppt
What happens to the density of seawater as its temperature increases?
Density decreases
What is the uppermost layer of the ocean called?
The surface layer or mixed layer
What drives surface ocean currents?
Wind patterns and the Coriolis effect
Which property of water helps regulate ocean temperatures?
High heat capacity
Which salt is most abundant in seawater?
Sodium chloride (table salt)
What are the two main factors influencing seawater density?
Temperature and salinity
In which ocean layer does the temperature decrease rapidly with depth?
The thermocline
What is the name of the large circular systems formed by surface currents?
Gyres
What causes the high surface tension of water?
The hydrogen bonding between water molecules
How does increased evaporation affect seawater salinity?
It increases salinity
Why is seawater denser in regions with high evaporation?
Because evaporation increases salinity
What is the temperature in the deep ocean typically near?
0°C
Name one current that transports warm water to higher latitudes
The Gulf Stream
Name two gases dissolved in seawater that are critical for marine life
Oxygen (O₂) and carbon dioxide (CO₂)
Which dissolved gas is essential for photosynthesis in marine plants?
Carbon dioxide (CO₂)
What is the relationship between depth and seawater pressure?
As depth increases, pressure increases
Why is the surface layer of the ocean biologically productive?
Because sunlight penetrates this layer, supporting photosynthesis
What is the process where cold, nutrient-rich water rises to the surface?
Upwelling
What is the term for the total amount of dissolved salts in seawater?
Salinity
Name one factor, other than salinity, that affects the amount of dissolved gases in seawater.
Temperature
What is the term for the circulation of deep ocean water driven by density differences?
Thermohaline circulation
How does the thermocline act as a barrier?
It separates warmer surface waters from colder, denser waters below
How does thermohaline circulation affect global climate?
It redistributes heat, regulates temperatures, and supports marine ecosystems.