Hydrosphere 1: Earth s Oceans. ppt. by Robin D. Seamon

Transcription

1 Hydrosphere 1: Earth s Oceans ppt. by Robin D. Seamon 1

2 D I S T R I B U T I O N 70 % of Earth s surface is water 4 bya water vapor condensed into shallows 1 big ocean, 5 major basins Pacific Atlantic Indian Arctic Southern VIDEO How Big is the Ocean? (5:30) 2

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4 C H E M I S T R Y Water is a solvent- it dissolves solutes of solids, liquids & gases Solute- substance that dissolves Solution- mixture of solvent and solute solution.html 4

5 C H E M I S T R Y GASES ATOMOSPHERE: 2 gases: Nitrogen, Oxygen ATMOSPHERE OCEANS: Dissolved gases: Nitrogen, Oxygen, carbon dioxide N O CO

6 Dissolved gases enter at rivers, streams, volcanic eruptions, decay, living organisms & through the water cycle 6

7 Effects of Temperature: Colder water dissolve gases better Warmer water cannot hold as many gases (remember global warming?) er5/lesson6 7

8 Carbon sink: ecosystem that absorbs more carbon than it lets out- oceans can hold carbon in the form of CO2 for thousands of years 8

9 Ocean chemistry is currently changing at an unprecedented rate. 9

10 SOLIDS Sea salts: 3.5% mass of oceans Elements- Chlorine (Cl) Sodium (Na) Potassium (K) Calcium (Ca) Magnesium (Mg) Sulfur (S) 10

11 WHY IS THE OCEAN SALTY? Salt: halite = 85% dissolved solids in ocean Salinity: measure of the amount of dissolved salts in a liquid halite 11

12 SALT ENTERS THE OCEAN: Chemical weathering of minerals from land into oceans Volcanic eruptions Chemical reactions between new sea floor & ocean water WATER IS CONSTANTLY BEING EVAPORATED, BUT SALTS REMAIN 3.6% 12

13 C H E M I S T R Y V A R I E S Latitude & climate affect concentration of salts- Warm oceans evaporate more water, leaving saltier water Arctic areas where sea water freezes & pushes out the salt, concentrates the salt in that area Rainy parts of the globe receive more precipitation, diluting salt water Slow moving water is saltier Areas where freshwaters empty into the ocean are less salty (brackish) 13

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16 D E N S I T Y Density= mass divided by volume Influencing factors: 1. Salinity (more salt = more dense) 2. Temperature ( cold water = more dense) *polar regions 16

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19 T E M P E R A T U R E Varies with depth & location Affected by solar energy DEPTH 19

20 ecuturesoceanogr/lecoceanstructure/lecstructure.html Can sea water freeze? Sea water can only freeze when it condenses such that it pushes out the salts first to make solid H 2O (28.4 F) floating ice insulates water below it, preventing it all from freezing WATER SALT 20

21 SURFACE WATER: LOCATION- Oceans are warmer near equatorial latitudes 21

22 TIME OF YEAR- seasons When the Northern Hemisphere faces away from the sun for Winter months, those oceans are cooler When N. Hemisphere points towards the sun for Summer, those oceans are hotter SUMMER in N Hemisphere WINTER in N Hemisphere 22

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24 TEMPERATURE ZONES DEPTH: Oceans get colder as you go deeper 1. Surface zone- top up to 300m, warmer and so less dense= difficult mixing with cooler waters below 2. Thermocline m, temperature drops faster here with depth; colder water is more dense; holds more dissolved gases, slower currents 3. Deep zone- 700m +, cold, slowest currents 24

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26 G L O B A L T H E R M O S T A T Oceans create climate Ocean water and air temperature are always trying to reach equilibrium (same temp) But it never happens due to earth s tilt & revolution AIR Temp WATER Temp AIR CHANGES TEMPERATURE FASTER THAN WATER 26

27 During summer months, ocean water absorbs solar energy from the atmosphere, trying to reach equilibrium with the hot air Before equilibrium can be reached, seasons change- air cools for autumn WARM Air Solar Energy COLD Air COLD Water WARM Water SUMMER WINTER 27

28 When air changes to cooler, winter temperatures, oceans start to release their stored warmth to now calibrate with the cooler air temperatures: WARM OCEAN BREEZES IN THE WINTER nice vacation spot! The opposite is true for Summer months: Air heats up, now oceans must absorb solar radiation to try and reach warmer equilibrium with the hot summer air: COOLER OCEAN BREEZES IN THE SUMMER nice vacation spot! 28

29 O C E A N C U R R E N T S Current: movement of ocean water that follows a regular pattern 29

30 Surface current: horizontal movements near surface, caused by wind Global winds Coriolis effect: earth rotates, making water arc instead of move in a straight line Continental deflections: currents can t go through continents! Deep currents movement of currents deep below the surface Form where density increases 30

31 Temperature & currents: CONVECTION- warm goes up, cold goes down Thermohaline- temperature and salt affect density & controls movement warm currents start at equator, move toward poles Cold currents move from poles to warm areas VIDEO: Making waves: the power of concentration gradients (5min) 31

32 G L O B A L C O N V E Y O R B E L T 32

33 Upwelling- movement of deep, cold, nutrientrich water to the surface The Importance of Upwelling 1 min) 33

34 AN EXAMPLE: El Nino local wind patterns (along South America) move local surface currents & so are replaced by deep cold water from below Cold, nutrient rich water from deep ocean rises to surface to replace warm surface water: Iron, Nitrates El Nino La Nina NOAA buoys study & predict VIDEO: El Nino (4:30) 34

35 C O L O R = H E A L T H Color is determined by which light waves are reflected into our eyes Blue wavelengths are slow Composition of organic materials or pollution can give ocean different hues Turqouise = phytoplankton 35

36 WHY IS IT IMPORTANT? Phytoplankton: microscopic plants that start the food chain reflect green light; water is greenish They need nutrients, so presence or absence of them tells the health of the ocean HAB (Harmful Algal blooms) Red Tide dinoflagellates 36

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38 M A P P I N G T H E F L O O R Sonar- sound navigation & ranging 1970 s satellites 1978: SeaSat network of satellites measuring ocean direction & speed of currents GeoSat measures changes in ocean depth 38

39 1977 Alvin- manned flight; discovered hydrothermal vents & ecosystem Deep Flight Deep Flight Alvin

40 Jason III & Medea

41 Continental shelf: gently sloping section of the continental margin between the shoreline and the slope PICTURE Continental slope: 200m-4,000m; steeply inclined section of the continental margin between the shelf and rise PICTURE Continental rise: base of slope; piles of sediment drop off PICTURE Abyssal plain: 4,000m + mud & decay PICTURE 41

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43 Mid-oceanic ridge: divergent boundaries; plates pull apart; lava bubbles up to make ridges PICTURE Rift valley: flat areas in rift zones PICTURE Ocean trenches: cracks in ocean basin; ocean plate slides under PICTURE Sea mounts: mountains under the ocean, formed on thin hot-spots in crust PICTURE 43

44 VIDEO: The Deep Sea; Exploring the Zones (6min) BACK 44

45 L I F E 1. plankton float near the surface, microscopic food for organisms 1. Phytoplankton: autotrophs 2. Zooplankton: heterotrophs 2. nekton: swim freely (fish, mammals, etc) 3. benthos: live on or near ocean floor (crabs, sponges, starfish, worms, seaweed, clams) VIDEO: The secret life of plankton (6 min) 45

46 Food Chain: shows how Energy flows from one organism to another Food Web: shows feeding relationships 1. aquatic 2. terrestrial VIDEO: A guide to the energy of the Earth (4:40) Interconnected: carbon from trees & debris support aquatic life amphibians live in both food for land animals 46

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48 M A R I N E Z O N E S Water depth Amount of sunlight 1. Intertidal zone: ocean meets land exposed to air part of the day waves, beaches 2. Neritic zone: deeper; floor slopes warm water, sunlight (corals, sea turtles, fish, dolphins, plankton, seaweed) 48

49 3. Oceanic zone: sea floor drops sharply Deep water of open ocean Plankton on surface, fish, whales, shark 4. Benthic zone: ocean floor No sunlight at deepest parts; cold Adaptations for low temp & no light- chemosynthesis begins food chain Bacteria, worms, sea urchins 49

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51 M A R I N E E C O S Y S T E M S 1. Intertidal areas: near shore Mudflats- worms, crabs, shorebirds Sandy beaches- worms, crabs, clams, plankton Rocky shores- live underwater & exposed to air MUDFLATS n_an_unconsolidated_shore_in_alaska.jpg 51

52 ROCKY SHORE SANDY BEACH VIDEO: Intertidal Biome (7 min) 52

53 2. Coral reefs: warm, shallow neritic zone Corals- living polyps form colonies over calcium remains of ancestors Second most diverse habitat (2 nd to RF) (algae, brightly colored fish, sponges, sea stars, sea urchins) VIDEO: What are Coral Reefs and what s their purpose? (5min) com/w/page/ /cor al%20polyp 53

54 3. Estuaries: where freshwater from river meets ocean water Rich in minerals Productive ecosystems Prone to pollution & runoff (Plankton, dolphin, manatee, seal, fish, plants, migratory birds, invertebrates) VIDEO: Estuarine Ecology (4:30) 54

55 4. Mangrove swamps: swamps along the coast of tropical areas Protect coastlines from erosion & damage from storms Breeding & feeding grounds for birds & other animals VIDEO: Into the mangrove Forest (6min) 55

56 5. Sargasso Sea- mid Atlantic Floating rafts of algae sargassum VIDEO: Big Changes in the Sargasso Sea (3min) 56

57 6. Polar ice: Arctic and Southern Oceans Rich in nutrients; plankton (Fish, birds, Beluga whales, penguins) 57

58 7. Pacific Garbage Patch VIDEO: The nurdles quest for ocean domination 5 min 58

59 FOOD O C E A N Multi-billion dollar industry R E S O U R C E S Fish, shrimp, oysters, crabs, mussels 75 million tons of fish/yr Overfishing Nets & trawlers damage wildlife (bycatch) Fish farms VIDEO: Overfishing (2:30) 400 tons of mackerel 59

60 Seaweed: kelp thickener for ice cream, Jell-O; Protein- Asian staple 60

61 NONLIVING RESOURCES 1. Oil & natural gas under layers of impermeable rock DRILL NONRENEWABLE Used up faster than can be replaced naturally 61

62 2. Freshwater Desalination removing salt water from water; expensive; Saudi Arabia Evaporation Heat Method: Burn/heat fossil fuels to evaporate & collect water vapor 62

63 Ocean Water Battery! 63

64 Desalination tent survival gear 64

65 Freeze methodfreeze ocean water to remove salt Ice Oil barrier Salt water 65

66 Reverse osmosis filtration pressure causes water to go through semi-permeable membrane: water can go through but salt & impurities cannot

67 3. Sea floor minerals: mineral nodules- ocean floor Manganese (to make steel) Iron, copper, nickel, Phosphates Nodules form from dissolved substances in sea water that stick to solid objects (rocks) 15% ocean floor covered in nodules Deep; difficult & costly mining

68 4. Tidal or Wave Energy: Energy from movement Water during high tide rushes through narrow coastal passageway Water s force can turn turbines to generate E *RENEWABLE clean, inexpensive 68

69 P O L L U T I O N Non-point pollution pollution from many sources Oil/gas leaked from cars Personal water craft leak Pesticides, herbicides from golf courses, farmland, home lawns 69

70 Point-source pollution pollution comes from a specific site (Leaking oil tanker, Factory, Wastewater treatment plan) nment/pollution_nonpoint.shtml VIDEO: Ganges River pollution 70

71 1. Trash dumping s scientists alarmed at type of trash washing on beachs; bandages, vials of HIV blood, syringes EPA investigated: 3 million tons of medical waste/yr has to now go into landfills Dumping in deeper ocean still common 71

72 2. Plastic- Plastic never decomposes Pacific garbage pack- kills wildlife 72

73 3. Sludge dumping- part of treated raw sewage By 1990 US had discharged 38 trillion liters of treated sludge into coastal waters Pollutes beaches; kills marine life Banned, but still practiced 73

74 4. Oil spills- tankers transport oil can spill 1990 double hulled tankers required by the Oil pollution Act (response to March 1989 Exxon Valdez spill in Alaska) Compliance has been slow

75 Gulf Coast spill April 2010 (3.2 million barrels of oil into the Gulf) BP Oil ts/o/oil_spills/gulf_of_mexico_2010/index.html VIDEO: Timeline of Gulf Oil Disaster (4min)

76 CITIZEN POWER 1980 s citizens organized beach cleanups Semi-annual Adopt-a-Beach program 76

77 1972 Clean Water Act put EPA in charge of issuing of permits for trash dumping into oceans 1972 US Marine Protection Research & Sanctuaries Act prohibits dumping any harmful material into marine environments 77

78 RESOURCES NC 8 th grade Holt Science & Technology: Holt, Rinehart & Winston,