Essential Question:Essential Question:

What role do Thermohaline What role do Thermohaline Circulation, Coriolis Effect Circulation, Coriolis Effect

and Upwelling play in and Upwelling play in Oceans?Oceans?

Ocean Currents

Wind-driven currents and tides are due to the gravity of moon and sun

Understanding Density

•The container represents volume

•The molecules represent mass

• The combination of the mass and volume is called DENSITY (heft).

•Density = Mass/Volume

Seawater is Denser than Freshwater

•Fresh water has H2O molecules that have lots of space between them, much like the cup of marbles• In a container (volume) there are only so many H2O molecules (mass)• The combination of the mass and volume of the water in a container is called the DENSITY (heft)•Is there volume (space) for something to be added that will only change the mass?•How will this impact density?

Water DensitySeawater is Denser than Freshwater

•Fill two beakers each with 200 ml water•Place ONE beaker on the scale and get the mass•Add ONE spoonful of salt – stir•How did this change the water level (volume)?•How did this change the water’s mass?•Why did the water level not change, but the mass level did?

How Does Freshwater and Saltwater Impact Oceans?

•Put a blue dye strip in the salty water and the red dye strip in the other – remove strips and dispose of them.

Water DensitySeawater is Denser than Freshwater

•Pour the water into the two chambers as shown here

Water DensitySeawater is Denser than Freshwater

•Carefully – without jiggling the box, pull the plastic divider out.Observe what happens – Why??

Thermohaline circulation (thermo=temperature, haline=salt)

Thermohaline circulation is the part of the ocean circulation which is driven by density differences. Sea water density depends on temperature and salinity. Differences arise from heating and cooling at the sea surface and the introduction of freshwater into the salty sea water. Heat sources at the ocean bottom play a minor role. 

Thermohaline circulation (thermo=temperature, haline=salt)

•As currents move water near cold areas, it gets colder (denser)• The wind evaporates water but not the salt seawater becomes saltier denser•Currents at the bottom of ocean that moves “packs” of water with different densities (combination of salt and temperature) around the globe THERMOHALINE CIRCULATION

Coriolis EffectCoriolis Effect

https://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm?chapter_no=visualization

Water is flowing across the moving Earth – thus currents within the ocean are impacted by this movement. The water “follows the curve” caused by Earth’s spin.

How does upwelling work?Wind + Coriolis force create a current flowN-hemisphere: right of wind directionS-hemisphere: left of wind direction“Gaps” are filled with water from below, thus:UPWELLING!!

Upwellings

How could you use your straw, the saran wrap and some water to simulate this action?

http://www.classzone.com/books/earth_science/terc/content/visualizations/es2405/es2405page01.cfm

UpwellingsNutrients accumulate in deep waters as they

move out of the photic zone (where nutrients get used up in photosynthesis) and  the remains of organisms sink and decompose  

Upwelling is the process by which deep, nutrient-rich bottom waters flow to the surface of the ocean

When the nutrients reach shallow water, where there is light, tiny algae (water plants) called phytoplankton use this as their primary nutrient source. These plants are the basis of the ocean food chain.

Upwelling areas are therefore very important for all animal life: from shrimp to blue whales

Aquatic LifeBigger sea-animals

eat tiny animals and ocean floor debris

They depend on areas where they can find lots of food, like upwellings

Source: http://www.youtube.com/watch?v=fOMzFFh3rEA