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The Marine Environment

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  1. The Marine Environment

  2. Exploration of the Ocean • Oceanography: • Oceanographers: study the ocean & its floor up to 6.4 km into the ocean floor • Ocean floor: is made up of continental & oceanic crust • Submersibles: underwater research vessels • Help oceanographers study the ocean depths • Bathysphere: early type of submersible used for deep-ocean diving • Remained connected to the research ship for communication & life support

  3. Submersibles • Bathyscaph: self-propelled, free-moving submarine used for deep-ocean diving • Can hold one pilot & 2 scientists • Has made new discoveries where life was thought to be non-existant • Robot submersibles: enable oceanographers to study the ocean at great depths & long periods of time

  4. SONAR:SOundNavigation And Ranging • Aid in mapping the ocean floor • Consists of transmitter & receiver • Sound waves are sent out, bounce off ocean floor & are reflected back to receiver

  5. SONAR

  6. Features of the Ocean Floor • Continental Margins: shallower portions of the ocean floor with thick wedge of sediments • Continental Shelf: shallow water at the edge of continents & ocean boundary • Affected by the rise & fall of sea level • Continental Slope: steeper slope of the seaward edge of a continental shelf • Boundary between continental & oceanic crusts • Submarine Canyon: feature carved into continental slope by fast moving currents

  7. Continental Margin

  8. Features of the Ocean Floor • Deep Ocean Basin: oceanic crust with a thin layer of sediment • Trenches: long, narrow deepest features on Earth’s surface • Abyssal Plain: extremely vast flat areas where the ocean depth is greater than 4 km • Covers about ½ the deep ocean basin • Mid-Ocean Ridges: continuous series of underwater mountain ranges that run along the ocean floors • Form when plates pull away from each other • Sea Mounts: submerged volcanic mountains at least 1000 m high • General associated with hot spots • If above earth’s surface they form islands (Hawaii) • Guyot/Tablemount: volcanic mountain with a flat top

  9. Deep Ocean Basins

  10. Shoreline Features • Beach: Area in which sediment is deposited along the shore • Beaches and shorelines are constantly undergoing changes as waves and currents act on them • Formation beaches and their features is caused by wave refraction: the bending of waves when they reach shallow water

  11. Features of depositional shores • Spit • Tombolo • Barrier island Figure 10-7

  12. Depositional Features • Spit: long narrow accumulation of sand with one end attached to the land and the other extending into the sea • Tombolo: an island is attached to the mainland by a narrow piece of land such as a spit • Barrier Island: long ridge of sand or other sediment deposited or shaped by currents separated from mainland

  13. Barrier island, New Jersey Figure 10-9c

  14. Features of erosional shores • Headland • Sea arch • Sea stack Figure 10-4

  15. Erosional Features • Headland: land, high and with a sheer drop, that extends out into a body of water • Sea Arch: opening eroded out of a cliff face • Sea Stack: blocks of rock isolated from the land by sea. Sea stacks begin as part of a headland. Erosion by waves erodes the softer, weaker parts of a rock first, leaving harder, more resistant rock behind

  16. Sea stack and sea arch, Oregon

  17. Protective Structures • Seawalls: built parallel to shore • Groins & Jetties: wall like structures built into the water perpendicular to the shoreline in order to trap beach sand • Breakwaters: built parallel to shoreline in water in front of beach

  18. Ocean Resources • Fresh water • Needed throughout the world • Possible to make through distillation, freezing, & reverse osmosis • Minerals • Nodules taken from deep ocean for making steel & other resources • Petroleum is the most valuable mineral taken from ocean

  19. Ocean Resources • Food • Aquaculture: farming of the ocean • Now restricted into zones for farming, fishing, recreation, & no touch-no take • Ocean-Water Pollution • Becoming more dangerous as we use harsh chemicals & dump them into the ocean • BP oil spill controversy estimated between 90-180 million gallons of oil • Plastic bottles and bags in oceans