Lesson 21 - NOAA

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Lesson 21 - NOAA Powered By Docstoc
					Lesson 21:
Marine Ecosystems

Marine Ecology
    Life in the marine environment

       We’ve learned a lot about the biology of different
        types of marine organisms

       In marine science, it is important to understand why
        these creatures live where they do and how they
        interact with their environment

       Today we will learn about marine ecology: the study
        of the relationship of marine organisms with each
        other and with the environment
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    Life in the marine environment

       The ocean can be divided into zones based on depth
        (vertically) and distance from land (horizontally)

       Different zones of the ocean have conditions that
        support different organisms

       What is an ecosystem?

       An ecosystem is a physically distinct area that
        contains a community of interacting organisms
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    Ocean zones and continental margins

       Many ocean zones are defined based on continental margins.
       To help you understand ocean zones, let’s first review
        continental Margins:
       Continental Margin: Submerged area of continents. Include:
        –   Continental Shelf (flat gradually sloping seafloor) from shoreline to ~
            200m; End of Shelf is called the Shelf Break
        –   Continental Slope (steeply sloping seafloor) seaward of shelf break
        –   Continental Rise (Moderately sloping seafloor) seaward of slope




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    Pelagic and benthic zones
                                                              Photos: NOAA

       One simple ocean zone
        classification is between the
        water and the ocean floor

       The water is referred to as the
        pelagic zone                          Shark: Pelagic (nekton)
        –   Organisms that swim through the
            water column are known as
            nekton

       The ocean floor is referred to
        as the benthic zone
        –   Organisms that live here are
5           benthic organisms or benthos      Crab: Benthic (benthos)
    Pelagic and benthic zone divisions

    Pelagic zone divisions        Benthic zone divisions
    (depth from surface)          (seafloor zones)
                                  Supralittoral –shore above high tide
    Epipelagic (0-200m)           Littoral – the intertidal zone (sometimes
                                  submerged and sometimes above water)
    Mesopelagic (200-1,000m)      Sublittoral – seafloor of the continental
                                  shelf (from low tide to the shelf break)
    Bathypelagic (1,000-4,000m)   Bathyl – seafloor of the continental slope
                                  to the deep ocean bottom
    Abyssopelagic (4,000-6,000m   Abyssal – deep ocean bottom between
                                  the base of the slope and 6,000 m
    Hadalpelagic (6,000-10,000m) Hadal – the deepest zone, below 6,000m
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      Pelagic and benthic zone divisions

                                           200m

                                           1,000m
    Littoral
                                           4,000m



                                                    Pelagic
                                                    zone



                                           6,000m




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    Species evolve traits that help them
    survive in their environment

       Species in different environments may evolve different
        lifestyles, behaviors and physical traits

       Do you remember a few ways that intertidal organisms
        are adapted to their relatively harsh environment?

       Species usually are not completely isolated from one
        another, but interact with other species that live in a
        shared environment

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    What is an ecosystem?
    Coral Reef                       Beach
     Populations    of different species interacting with one
        another in a shared environment form a community

       An ecosystem is a distinct physical entity with
        unique abiotic (nonliving) conditions that is home to
                                     Intertidal (Splash zone)
        a community of interacting species

       Can you think of some marine ecosystems you have
        learned about in earlier lessons, classes or
        elsewhere?
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      Energy is transferred through ecosystems

                                      Secondary
                                      consumers eat
                                      primary
                    Solar energy      consumers to
                    is converted to   get energy
                    chemical
                    energy by
                    autotrophs




                                                      Primary
                                                      consumers eat
                                                      primary
                                                      producers to
10                                                    get energy
     Photos: NOAA
     Life in ecosystems is interconnected

        As you’ve probably already realized, the marine
         environment consists of many distinct ecosystems that
         contain unique organisms
        How do you think life within ecosystems is
         interconnected?
        Marine organisms form relationships with one another
         and share space and resources
        As a result, an impact on a single species in an
         ecosystem can affect many other species in the same
         ecosystem

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     Important interactions
                                                                           Photo: NOAA

        It is important to manage our
         natural resources in a way that
         reflects the interconnectedness of
         ecosystems and their
         components

        Ecosystem-based management
         (EBM) is a management
         approach that includes these
         interactions instead of       Management of ecosystems, like this bleached
         considering single species or coral reef, requires looking beyond just the
         single issues at a time       coral itself. Other important factors to study
                                              might include pollution, development,
        NOAA applies EBM in its              watershed management and interactions with
         management of marine resources       other species.
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     Student activity: Ecosystem case study on
     an estuary

        An estuary is a body of water that forms where
         freshwater from rivers and streams flows into the ocean
         and mixes with seawater to form a unique and productive
         ecosystem
        One of our nation’s most valued ecosystems, the
         Chesapeake Bay, is an estuary
          – In fact, it is one of the largest estuaries in the world
        In today’s exercise, you will analyze data about the blue
         crab to make inferences about the health of the
         Chesapeake Bay ecosystem

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posted:3/25/2013
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