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Ch 19 ppt

Ch 19 ppt






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    Ch 19 ppt Ch 19 ppt Presentation Transcript

    • The Seafloor Section 1
    • Seafloor geography
      • Continental shelf – the gradually sloping end of a continent that extends under the ocean
        • Atlantic coast – 100 km – 350 km into the sea
        • Pacific Coast – 10 km – 30 km
        • Ocean depth at continental shelf – avg. 200 m
    • Continental slope
      • Extend from edge of continental shelf to the ocean floor
      • Descends from 200 m to 4,000 m deep
    • Abyssal Plains
      • Sediments constantly settle on the bottom filling in valleys creating flat seafloor called abyssal plains
        • Ocean depth at abyssal plain – 4,000 m to 6,000 m
      • Seamounts – under-water inactive volcanic peaks
    • Volcanic Island
      • Volcano that breaches the surface of the water forming an island
    • Mid-ocean Ridges
      • The area in an ocean basin where new ocean floor has formed
        • Forms due to oceanic plates moving apart and lava hardening
    • Subduction Zones
      • Subduction zones are marked by trenches – long, narrow steep sided depression where one crustal plate sinks beneath another
      • Mariana Trench 11 km ( 10,000 m) below sea level (deeper than Mt. Everest is tall)
    • Seafloor Mineral Resources
      • 1 - Continental Shelf
        • petroleum and natural gas deposits
        • Sand and gravel can be dredged
        • Rivers deposit minerals that are concentrated in one place by ocean currents called placer deposit
      • 2 - Deep Water Deposits
      • Hot water comes out of cracks near mid-ocean ridges and quickly cools causing minerals to fall out
        • Ex: sulfur, iron, copper, silver, zinc
      • Hard to mine economically b/c so deep
      • How would you mine them?
    • Section 2 Life in the Ocean
    • Photosynthesis
      • Using energy from sun to produce energy
      • Sun goes through water up to 100 m deep
    • Producers/Consumers
      • Producers – org. that produce their own food
        • ex: algae, seaweed, kelp, phytoplankton
      • Algae in oceans are an important source of oxygen
      • Consumers – org. that eat (consume) producers
        • Ex: shrimp, fish, dolphins, sharks, killer whales
    • Food Chain/Food Web
      • Org. transfer energy from one to another
      • Ex:
      • algae copepods herring cod
      • seal killer whale
    • Chemosynthesis
      • Org. such as bacteria that chemosynthesize or use sulfur to create energy
    • Reproduction
      • Corals and sponges release reproductive cells into water for currents to distribute
      • Others like salmon and sea turtle return to the same place each year to spawn or nest
    • Ocean Life
      • Most org. live above continental shelf since most of food is located here
      • b/c relatively shallow & sun passes to the bottom
    • Plankton
      • Org. that drift with the current
        • Ex: algae and jellyfish
      • Phytoplankton – producers – plants that drift
      • Zooplankton – consumers – hatchlings, crabs, diatoms
    • Nekton
      • Animals that actively swim
        • Ex: fish, whales
      • Org. control buoyancy using air bladder
      • Bioluminescence – luciferin molecule – used to attract bait, defense mechanism
    • Benthos
      • Plants/animals living on the seafloor
        • Ex: sea cucumber, sea urchins, flounder, sea anemone, sponges
    • Beach Habitat
      • Sand fleas/mole crabs, worms
      • Makes holes in sand when water covers holes they filter feed
      • Where sand is constantly covered – fish turtles horseshoe crabs
      • Org. deal with lots of change
    • Rocky Shore Habitat
      • Starfish, anemones, mussels, barnacles, attach to rocks
      • Tide pools area where water remains during low tide
        • Good place to lay eggs b/c safe from predators
    • Estuary
      • Area where mouth of a river opens into an ocean, lots of biological life
      • Brackish water – fresh water & salt water mix
      • Great place for hatchlings – many plants for protective cover and food
      • Important economic food source
      • Oysters, shrimp, clams, crab
    • Chesapeake Bay
      • VA’s estuary
      • Very easy to pollute b/c rivers flow directly in them
      • Pollutants:
        • Pesticides, herbicides, insecticides, oil, biosolids, fertilizers
    • Coral Reefs
      • Coral thrive in sunlit warm water
      • Animal build hard calcium capsules around its body
        • Calcium from ocean
      • Reef forms as org. connect to each other
      • Other animals begin to live there
    • Section 3 Ocean Pollution
    • Pollution
      • Anything not native to the environment that causes damage to org. by interfering w/ their life processes
      • Oceans are environmentally and economically important
      • Human activity have consequences for the ocean
    • Pollution Introduction
      • 4 ways:
        • Deliberate dumping
        • Lost overboard accidentally
        • Air pollutants the enter through rain
        • Carried by rivers - runoff from lawns (herbicides), crop fields, construction sites (sediment)
    • Sewage
      • Combined Sewage Overflow – Lynchburg
      • Algal blooms – caused by fertilizers, sewage inc. amount of algae, algae dies, bacteria that decompose use up all oxygen, cause fish kills
    • Chemical Pollutants
      • Pesticides, insecticides, herbicides
      • Industrial waste contain heavy metals like mercury and lead, polycarbonated biphenyls (PCBs)
      • biological amplification – when harmful chemicals can build up in the tissues of organisms that are at the top of the food chain
    • Oil
      • Mostly from runoff of streets, parking lots, dumped into drains/ground
      • Oil spills – use bacteria that eat oil and change its chemical composition called bioremediation
    • Solid Waste
      • Balloons, plastic bags sea turtles eat mistaken for jellyfish
      • Biohazardous waste – needles can make beaches unsafe
    • Sediment
      • Forestry, construction, agriculture not practicing good erosion control techniques
      • Sediment covers coral reefs & fill estuaries
    • Bathymetric Maps
      • Isobaths – contour lines used to measure areas of equal depth