Sea Water Basics
What do we call the amount of salt in seawater?
Salinity
Is ocean water warmer at the surface or in the deep?
At the surface
What are large circular ocean current systems called?
Gyres
What causes air to rise at the equator and sink at the poles?
Uneven heating by the sun
What is it called when deep, cold, nutrient-rich water rises to the surface?
Upwelling
What is the average salinity of ocean water (in PSU)?
About 35 PSU
What is the zone of rapid temperature change with depth called?
Thermocline
What is the name of the warm current along the U.S. East Coast?
The Gulf Stream
What are the winds called that blow from east to west near the equator?
Trade Winds
Upwelling zones usually have high or low biological productivity?
High
Which two factors affect seawater density the most?
Temperature and salinity
Why is deep ocean water usually cold?
Because sunlight doesn’t reach it
What causes the Coriolis Effect?
Earth’s rotation
Which cell lies between 30° and 60° latitude?
Ferrel Cell
What happens during an El Niño event?
Trade winds weaken and warm water moves east
What happens to salinity when sea ice forms?
It increases
What happens to the density of seawater when it gets colder?
It becomes denser and sinks
In which direction do gyres rotate in the Northern Hemisphere?
Clockwise
What effect makes winds and currents turn right in the Northern Hemisphere?
Coriolis Effect
What happens to coastal upwelling during El Niño?
It decreases (less cold water rises)
Name two major ions found in seawater.
Chloride (Cl⁻), Sodium (Na⁺) (others: sulfate, magnesium, calcium, potassium)
Name the three main layers of the ocean in order from top to bottom.
Surface layer, thermocline, deep layer
What is the deep ocean circulation called that’s driven by temperature and salinity?
Thermohaline circulation (the “global conveyor belt”)
What is the name of the fast-moving air current near the top of the troposphere?
Jet Stream
What do we call the sinking of surface water to deeper layers?
Downwelling