Do Now

1. Do Now • What is the difference between an ocean & a sea? • List 2 oceans & list 2 seas

2. Ocean Chapters 23 & 24

3. Ch. 23 sec 1 Global Ocean - body of salt water that covers nearly three-fourths of Earth’s surface • contains more than 97% of all of the water on Earth • divided into five major oceans: 1. Pacific Ocean Largest 2. Atlantic Ocean 3. Indian Ocean 4. Southern Ocean 5. Arctic Ocean Smallest

4. Seas Sea - large, commonly saline body of water that is smaller than an ocean & that may be partially or completely surrounded by land • Ex. Mediterranean Sea, Caribbean Sea, & South China Sea

5. Oceanography Oceanography - scientific study of the ocean, including the properties & movement of ocean water, the characteristics of the ocean floor, & organisms that live in the ocean

6. Studying the Ocean Depths Sonar (sound navigation and ranging)- a system that uses acoustic signals & returned echoes to determine the location of objects or to communicate • used to make maps & profiles of the ocean floor

8. Studying the Ocean Depths Submersibles - underwater research vessels • Bathysphere - remains connected to the research ship for communications & life support • Bathyscaph - is a self-propelled, free-moving submarine

9. Ch. 23 sec 2 The ocean floor can be divided into two major areas: 1. Continental margin shallow sea floor located between the shoreline & the deep-ocean bottom 2. Deep-ocean basin - part of the ocean floor that is under deep water beyond the continental margin Deep- ocean basin

10. Features of the Ocean Floor Trenches - long, narrow, & steep depression that forms on the ocean floor

11. Abyssal plain - large, flat, almost level area of the deep-ocean basin

12. Mid-ocean ridges - form underwater mountain ranges that run along the floors of all oceans

13. Seamounts - submerged volcanic mountains that are taller than 1 km. They form in areas of increased volcanic activity called hot spots.

14. Sea Floor Topography

15. Do Now • What does sonar stand for & what is it used for?

16. Ch. 24 sec 1 Ocean water is a complex mixture of chemicals that sustains a variety of plant & animal life. • The main gases dissolved in ocean water = O2 & N2 • Gases can enter the ocean from streams, volcanoes, organisms, & the atmosphere. • Ocean water is 96.5% pure water, or H2O • Dissolved solids, commonly called sea salts, give the ocean its salty taste.

17. Salinity & The Thermocline Salinity - measure of the amount of dissolved salts in a given amount of liquid Thermocline- layer in a body of water in which water temperature drops with increased depth faster than it does in other layers

18. Ocean Color The color of ocean water is determined by the way it absorbs or reflects sunlight. • Much of the sunlight is absorbed by the water • Only the blue wavelength tends to be reflected • The reflection makes ocean water appear blue

19. Do Now • What are three classifications of marine life? • What do we base these groups on?

20. Ch. 24 sec 2 Marine organisms help maintain the chemical balance of ocean water. • removing nutrients & gases • nutrients are eventually returned to the water when the organism dies

21. Upwelling Elements are then released back into the ocean water when organisms die, sink to lower depths, & decay. So, deep water is a storage area for nutrients needed for life. Upwelling- movement of deep, cold, and nutrient-rich water to the surface

22. Three Groups of Marine Life • Organisms are placed in groups based on where they live and how they move • Plankton • Nekton • Benthos

23. PLANKTON • Organisms that float or drift freely near ocean’s surface • Microscopic • Food for many organisms • Phytoplankton • plant like • Provides most of Earth’s oxygen 2. Zooplankton • animal like

24. NEKTON • Swim actively in open ocean • mammals like whales, dolphins, & sea lions • fish

25. BENTHOS • Live on or in ocean floor • Crabs, starfish, worms, coral, sponges, seaweed, and clams

26. Ocean Environments Benthic (BOTTOM) zone- bottom region of oceans & bodies of fresh water Pelagic zone- region of an ocean or body of fresh water above the benthic zone The amount of sunlight, the water temperature, & the water pressure determines the distribution of marine life within these zones.

28. Benthic (BOTTOM) Zones Intertidal zone - shallowest, between the low-tide and high-tide lines Sublittoral zone - most organisms live here Bathyal zone - begins at continental slope - 4,000 m. Abyssal zone - no sunlight , 4,000 m - 6,000 m. Hadal zone - ocean trenches, deeper than 6,000 m

29. Pelagic Zones Neritic zone - area of the pelagic zone above the continental shelve Oceanic zone - extends into the deep waters & divided into four zones, based on depth: • Epipelagic SHALLOW • Mesopelagic • Bathypelagic • Abyssopelagic DEEPEST

30. Zones

32. Ch. 24 sec 3 Food from the Ocean Because fish are a significant food source for people around the world, fishing has become an important industry. When the ocean is overfished, or overharvested, over a long period of time, fish populations can collapse.

33. Fresh Water from Salt Water? Desalination – extraction of fresh water from salt water • Distillation • Ocean water is heated to remove salt • Freezing • Freezing water to remove salt • Reverse Osmosis Desalination • Uses special membranes to filter salt All methods are time consuming & costly!

34. Minerals & Resources • Salt • Petroleum – most valuable (oil) ¼ of the world’s oil comes from offshore wells • Nodules – potato-shaped lumps of minerals (manganese, iron, copper, nickel, cobalt, & phosphates) from ocean floor Expensive & dangerous to obtain • Magnesium • Bromine

35. Food Aquaculture- raising of aquatic plants and animals for human use or consumption Problem:ocean farms are susceptible to pollution