1. Waves & Tides MOTION IN THE OCEAN

2. Waves  A disturbance which moves through or over the surface of a fluid  Mostly caused by winds (Also earthquakes, volcanoes, grav. pull) (Also earthquakes, volcanoes, grav. pull)  Form of great energy

3. Wave Characteristics  Parts of a Wave Crest = high point Crest = high point Trough = low point Trough = low point Height = vertical distance from crest to trough Height = vertical distance from crest to trough Wavelength = Horizontal distance between crest to crest or trough to trough Wavelength = Horizontal distance between crest to crest or trough to trough

4. Size of Wind Generated Waves  Depends on 3 things : Wind Speed Wind Speed Wind Duration (length of time wind blows) Wind Duration (length of time wind blows) “Fetch” Extent of open water across which the wind can blow “Fetch” Extent of open water across which the wind can blow

5. Water Motion in Waves  Water travels in vertical circular orbits  Wave moves, particles don’t!

6. Importance of Waves  Shaping Coastlines Erode cliffs Erode cliffs Grind rock into sand Grind rock into sand  Ecology Returns O 2 to water Returns O 2 to water Stir up food for filter feeders Stir up food for filter feeders

7. Types of Waves CHOP – Short period (back bays) SWELL – Long period (boat rolls; seasickness) SWASH – water up beach BACKWASH – back down

8. Creation of a Tsunami

9. Tides  The rhythmic rise and fall of the ocean’s water High tide = rising, incoming tide, flow Low tide = receding, outgoing tide, ebb Slack tide = vertical movement stops

10.  Tides are very long, slow waves They have a wave period of 12 hours 25 min They have a wave period of 12 hours 25 min Tidal day is 24 hours 50 min Tidal day is 24 hours 50 min NJ has 2 high and 2 low tides daily NJ has 2 high and 2 low tides daily

11. 1. Gravitational pull of sun & moon on Earth What Causes Tides? Moon closer, therefore > effect Like magnet, pulls water away from surface = TIDAL BULGE

12. 2. Centrifugal Forces Produced by motions of Earth, sun, & moon Bulge on opposite side because centr. force > pull of moon

13. Types of Tides 2x’s/month 2x’s/month Spring Tide - Moon and sun are in direct line with one another - Results in unusually high tidal range -Tidal Range = vertical distance between high & low tides

14.  Neap Tide sun and moon are at right angles sun and moon are at right angles Pulls cancel each other out – causes a weak pull Pulls cancel each other out – causes a weak pull unusually low tidal range unusually low tidal range 2 x’s / month 2 x’s / month

15. Spring vs. Neap Tides

16. Types of Tides Continued  Diurnal Tides 1 high & 1 low / day 1 high & 1 low / day Parts of Gulf of Mexico and Asia Parts of Gulf of Mexico and Asia  Semi-Diurnal Tides 2 high & 2 low / day 2 high & 2 low / day Atlantic coasts of North America and Europe Atlantic coasts of North America and Europe  Mixed 2 high & 2 low / day (height varies) 2 high & 2 low / day (height varies) Pacific coast Pacific coast

17. Importance of Tides Expose & submerge orgs Circulate water in bays & estuaries Trigger spawning (grunion, horseshoe crab) Circulates food, wastes, etc

18. Localized Surface Currents Longshore Current. Flows parallel to shore; move sediment Flows parallel to shore; move sediment

19. RIP CURRENT - Caused by converging longshore currents - Very dangerous ; Red Flag - DO NOT fight rip current; swim parallel to shore to get out of channel

21. The Intertidal Zone  The intertidal zone is the area located between high tide and low tide  Strandline- the long line of seaweed and debris deposited on the beach during each high tide

23. Organisms of the Intertidal Zone  Ex. Crustaceans, worms, mollusks  Well adapted to meeting the challenges of living in an area that has alternating periods of wet and dry

25. The Supratidal zone – “Splash Zone”  The part of the beach where you lay your beach towel  The area above the intertidal zone, up to the sand dunes  Upper supratidal zone- less salt spray and many species of grasses, shrubs & trees  Only gets wet during storms or other high water events

27. The Subtidal Zone  The area of heavy wave impact below the low tide line  Organisms in the subtidal zone: Have structures that help them cling to hard substrates Have structures that help them cling to hard substrates Ex. Encrusting sponges, sea stars, marine snails, anemones, barnacles, kelpEx. Encrusting sponges, sea stars, marine snails, anemones, barnacles, kelp

29. Organisms in the subtidal zone (Con’t)  Many organisms have flat bodies that minimize exposure to wave impact Ex. Flounders & sand dollars Ex. Flounders & sand dollars

31. The Surf Zone  Region of crashing waves  Not a fixed zone, but moves with the tide  Organisms of surf zone: Life is like living in a storm Life is like living in a storm Ex. Mole crab, surf clam, sand crab, blue crab, silverside fishes Ex. Mole crab, surf clam, sand crab, blue crab, silverside fishes

33. Four major zones of life: 1. Upper Intertidal Zone 1. Upper Intertidal Zone Wave splash zoneWave splash zone Area above high tide zone that gets moisture from ocean sprayArea above high tide zone that gets moisture from ocean spray Blue-green bacteria, periwinkle snail, limpetBlue-green bacteria, periwinkle snail, limpet

36. 2. Mid-Intertidal Zone  Lies below the upper intertidal zone  Occupied by barnacles, mussels, & seaweeds  Rockweed provides cover for other marine animals such as snails, limpets, small crabs & worms

37. 3. Lower Intertidal Zone  Below the bed of mussels  Dominated by seaweeds  Creates a “carpet” that helps retain water and create tide pools Tide pool- natural aquarium on the rocky shore that contains algae, snails, crabs and small fish Tide pool- natural aquarium on the rocky shore that contains algae, snails, crabs and small fish

39. 4. The Subtidal Zone  Below the lower intertidal zone  Underwater  Best way to observe life is by snorkeling  Organisms include: Sea urchins Sea urchins Snails Snails Sea stars Sea stars Sea anemones, crabs, lobsters, Sea anemones, crabs, lobsters,

42. The Estuary Environment  Estuary- an environment along the coast where freshwater rivers drain into the ocean and mix with saltwater Varied terrain Varied terrain brackish water (mix of fresh and salt water) brackish water (mix of fresh and salt water) Provides diverse habitats for marine life Provides diverse habitats for marine life One of the most productive coastal environments One of the most productive coastal environments

43. The Salt Marsh Community  Also known as wetlands  Where grasses grow abundantly in shallow water  Calm, nutrient rich waters provide a great place for offspring and juveniles to grow to maturity  Often called the “nursery”

44. Organisms of the salt marsh  Cordgrass  Ribbed mussel  Common shore shrimp  Fiddler crabs  Hermit crabs  Flounders  Killifish  Marine birds

46. The Mud Flat Community  Dark, muddy sand  No marsh grasses  Little wave impact  “graveyard” of the estuary  Where organic debris carried in by the tides  Foul odor from decay

47. Organisms of the Mud Flat  Mud snails  Sandworms  Bloodworms  Soft-shell clam  Razor clam

49. The Mangrove Community  Shores and bays in tropical regions that are covered in mangrove trees  Dominant species is Red Mangrove  Arching roots visible at low tide Traps organic debris Traps organic debris Products of decay provide nutrients for microscopic and small organisms Products of decay provide nutrients for microscopic and small organisms

50.  Protect the shore from erosion  Hold the sand and prevent it from being carried away by waves and currents  Protects the inland habitats from storms