Spring Hydrology 2016 Mrs. Kummer

The Water Planet  Nearly ¾ of Earth’s surface is underwater  97% of all water on Earth is in the “global ocean”  The global ocean is only massive as a surface area….as a volume and mass it is tiny  Volume of solid earth = 800X greater than that of water in the global ocean  Mass of global ocean is only 1/4,000 of Earth

What Parts Make Up the Global Ocean? How many Oceans are there? 5 total: Pacific, Atlantic, Indian, Arctic, and Southern-NOAA does NOT consider this an ocean How many seas are there? Many! Examples? All Oceans and Seas are saltwater (CH21) NOAA = National Oceanic and Atmospheric Administration

What are some features of these oceans? Pacific Ocean is the largest feature on Earth Contains > ½ of the ocean water on Earth Average depth = 3.9km (almost 3 miles) makes it the deepest Contains: Sea of Japan, Bering Sea, South China Sea Atlantic Ocean is the next largest Average depth = 3.6km Contains: Mediterranean, Caribbean, and Baltic Seas Indian Ocean is the next largest Average depth = 3.8km Contains Arabian and Red Seas Southern Ocean is the next largest Arctic Ocean is the smallest

What is Oceanography? Study of physical characteristics, chemical composition, and life forms of the ocean Benjamin Franklin first mapped the gulf stream in (even though sailors used it for 200 years before he named it…) The birth of Oceanography was when the superintendent of the US Naval Observatory, Matthew Maury, spent his career on Oceanography He released his book in 1855 and distributed it globally It is considered one of the “newer sciences” like Physics/Calculus/Nuclear Energy

How Do You Explore the Ocean Floor?

Continental Margin That portion of the seafloor adjacent to the continents; it may include the continental shelf, continental slope, and continental rise.

Continental Shelf The gently sloping surface at the base of the continental slope.

Continental Slope The steep gradient that leads to the deep- ocean floor and marks the seaward edge of the continental shelf.

Submarine Canyon A seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower; a canyon carved into the outer continental shelf, slope, and rise by turbidity currents.

Turbidity Current A downslope movement of dense, sediment-laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension.

Continental Rise The gently sloping surface at the base of the continental slope.

Ocean Basin Floor Area of the deep-ocean floor between the continental margin and the oceanic ridge.

Abyssal Plains Very level area of the deep-ocean floor, usually lying at the foot of the continental rise.

Seamounts An isolated volcanic peak that rises at least 1000 meters above the deep-ocean floor.

Mid-Ocean Ridge A continuous elevated zone on the floor of all the major ocean basins and varying in width from 1000 to 4000 kilometers.

Seafloor Spreading The process by which plate tectonics produces new oceanic lithosphere at ocean ridges.

Key Concept

What are the three main regions of the ocean floor? The floor regions are: continental margins, ocean basin floor, and mid- ocean ridge.

Key Concept How do continental margins in the Atlantic Ocean differ from those in the Pacific Ocean? The Atlantic Ocean has thick layers of undisturbed sediment cover with very little volcanic or earthquake activity. The Pacific Ocean crust is plunging beneath continental crust and experiences both volcanic and earthquake activity.

Key Concept How are deep-ocean trenches formed? Trenches are formed at sites of plate convergence where one moving plate descends beneath another and plunges back into the mantle.

Key Concept How are abyssal plains formed? The sediments that make up abyssal plains are carried there by turbidity currents or deposited as a result of suspended sediments settling.

Key Concept What is formed at mid-ocean ridges? New ocean floor is formed at mid- ocean ridges as magma rises between the diverging plates and cools.