Notes Part 1: Oceans are connected! Chapter 3: Oceans Notes Part 1: Oceans are connected!

Facts about the Ocean 71% of all water on Earth is salt/sea water There are 4 oceans….but they are all connected to form 1 sea. Pacific, Atlantic, Indian, and Arctic

Facts about the Ocean

Why is Earth mostly water? Dense materials (rock, metals, etc…) sank Water vapor rose to the surface Temperatures cooled and the water vapor condensed.

Natural Resources The ocean contains several resources that we use on a daily basis: Food – the US is the 3rd largest consumer of seafood Provides oxygen Chemicals – some make medicines, such as cancer-fighting treatments

Salt Salinity: the amount of dissolved salt in H2O Processes can remove salt from the sea (desalination) but the salinity of the water does not change.

Salt Water and Density Salt water has a greater density than fresh water… Ocean water is most dense: In shallow areas Warm climates VERY cold climates

Other Minerals Underwater volcanoes erupt minerals into the sea. Rain and rivers carry minerals to the sea The ocean contains all 92 natural elements

Gases in the Ocean Dissolved oxygen (O), nitrogen (N), and CO2 Ocean animals take in O and release CO2 O is added by algae and other plants CO2 is used to help build shells for animals

Ocean Temperatures 1. Surface: the warmest layer because it is heated by the sun 2. Thermocline: warmer at the top, but temps drop quickly with depth 3. Deep water: cold all year… 32-37 degrees F

Notes Part 2: Ocean Features and Currents Chapter 3: Oceans Notes Part 2: Ocean Features and Currents

Ocean Features

Continental Shelf The gradual sloping land between the edge of a continent and the continental slope

Continental Slope Land that drops steeply at the end of the continental shelf

Submarine Canyons Canyons that cut through the continental shelf and slope

Ocean Trench Narrow, steep clefts in the ocean floor

Abyssal Plain Wide, flat area of the ocean floor covered with sediment

Mid-Ocean Ridge/Seamounts Chain of underwater mountains Single underwater mountain Mid-Ocean Ridge/Seamounts

Volcanic Islands Underwater volcanoes that reach the surface

Ocean Exploration With today’s technology, scientists are able to map the ocean floor They use sonar to find depths by using sound waves to measure distances and locate objects. Fast echo = shallow Slow echo = deep

Ocean Exploration Scientists also use satellite imaging to detect bumps and dips in depth

Ocean Currents Section 3.2

What is an ocean current? A mass of moving water found in the ocean. Water and winds work together to move cold and warm temps around the world El Nino occurs if the winds do not help carry the weather There are surface currents and deep currents.

Surface Currents Strong winds blow over the ocean causing these. They only go down 100-200 meters There are giant whirlpools in the northern (clockwise) and southern (counterclockwise) hemispheres. Warm water is moved away from the equator, and cold air is pushed toward it.

Surface Currents

Deep Currents Caused by differences in the water densities. Water becomes dense from salt and sinks to the bottom, moving along the ocean floor.

Deep Currents Downwelling: movement of water from the surface to the ocean floor. Water brings oxygen down to support life. Upwelling: movement of water back to the surface. Returns many nutrients to surface.

Notes Part 3: Waves and Tides Chapter 3: Oceans Notes Part 3: Waves and Tides

Important Terms Wave: up and down movement in the water. Crest: high point of the wave Trough: low point of the wave Wave height: distance from the top of the crest to the bottom of the trough. Wave length: distance between one wave’s crest and the next wave’s crest.

Important Terms

Wave Action at the Surface It may look like waves are moving the water, but they are not. Currents move water, waves move energy

Wave Action near Shore Waves lose speed and energy as they approach the shore, and eventually “break” The water runs back down the sand into the ocean. Undertoe: the pull of the water as it runs back to the sea Very dangerous!

Waves cause Currents: Longshore currents Moves water parallel to the shore Occurs when waves meet the land at an angle Can form sandbars: long piles of sand that form parallel to the coast

Waves cause Currents: Rip Currents Narrow streams of water that break through sandbars and drain rapidly back into the ocean. Occur when high winds or waves cause excess water movement.

Ocean Tides Section 3.4

What is a tide? The periodic rising and falling of the water level in the ocean Highest water level at high-tide Lowest water level at low-tide

Daily Tides The moon’s gravitational pull pulls on the water facing it, causing a bulge. The moon’s gravitational pull also pulls Earth toward it, causing a bulge on the opposite side.

Tidal Range As Earth rotates, the high tide moves. Tidal range: the difference in height between a high tide and a low tide. the range is greater in a narrow bay compared to the open shore An area with a steep ocean floor also has a larger range

Tidal Range

Monthly Tides In a month, the moon, sun, and Earth all line up 2 times (at the new and full moons) The gravity of the moon adds to the gravity of the sun and they both pull Earth’s water in the same direction. Creates an extra-high tide and extra-low tide known as the spring tide.

Monthly Tides During the 1st and 3rd quarter moons, the Sun and the moon do not align. The gravity of them pulls Earth’s water in different directions. Causes the tides to be less extreme, known as a neap tide.

Tides and Electricity A tidal dam is built near the coast. Water flows in at high tide and is locked in with gates. When the low tide comes, the water rushes out and falls on the turbines.

Tides and Electricity Few places can use it Timing does not match up Pros Less Pollution Renewable Energy source Cons Few places can use it Timing does not match up Could harm marine life