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Unit IV Notes- Marine Ecology


									Unit IV Notes-
Marine Ecology
I. Energy
 A. Matter and Energy
Life requires both matter and
 energy to exist.
 –Matter that makes up living
  organisms consists of about 13
  of 118 known elements.
   • Carbon, Hydrogen, Nitrogen, and
     Phosphorous are four major
Law of conservation

Energy/Mass  cannot be
 created nor destroyed; it can
 only be changed from one
 form to another.
B. Autotrophy and Heterotrophy
 Most marine organisms get their energy
  directly or indirectly from the sun.
 Autotrophy- process of self-feeding by
  creating rich compounds called
  carbohydrates (i.e. plants, algae,
 Heterotrophy- process of getting energy
  and matter by consuming other organisms
  (i.e. zooplankton, fish, etc.)
C. Respiration

 Both autotrophs and heterotrophs must
  convert carbohydrates into useable
 Done through cellular respiration:

    C6H12O6 + 6O2 → 6CO2 + 6H20 + ENERGY
 D. Photosynthesis

    Process of using light energy to create
     carbohydrates from inorganic

6CO2 + 6H20 + LIGHT ENERGY → C6H12O6 + 6O2
    D. Photosynthesis cont.

 Organisms that perform this are called
  autotrophs, which are also known as
  primary producers.
 Carbohydrates are the basic building
  block of all larger molecules
  characteristic of life on earth.
 Even producers use cellular respiration.
E. Aerobic and Anaerobic
 Aerobic   respiration- uses
 Anaerobic respiration- used by
  organisms in environment
  without oxygen.
    F. Chemosynthesis
   Process of using chemicals to create
    energy-rich organic compounds.
     – Similar to photosynthesis because it
       produces carbohydrates.
     – Differs because it does not use sunlight
       as energy source, but chemical energy
       in inorganic compounds.
     – Not as efficient as photosynthesis.
     – Used by bacteria that live on the ocean
     II. Primary Production

 This is the base of an ecosystem.
 In the ocean there are several producers,
 The land is only slightly more productive than
  the ocean.
 Marine plants and algae are responsible for
  producing a fair amount of dissolved oxygen in
  the ocean.
 However, a very important group of primary
  producers are the plankton.
A  wide variety of organisms that
  share a habitat and lifestyle
 Not one species, but include many
  species from virtually every major
  group of organisms found in the sea.
 They can be autotrophic or
Types of Plankton
 Account for 92-96% of oceans
  primary productivity
 These are the only plankton that
  are producers (they can undergo
 Examples: Diatoms and

   Primary and Secondary consumers that
    feed on phytoplankton and other
    heterotrophic plankton.
   Largest Plankton in the sea is the Mola
    Mola or Ocean Sunfish (it is also the
    largest bony fish).
Limiting Factors

 Physical or Biological necessities that
  restrict survival of primary producers.
 Too much or too little will reduce
  population of an organism.
 1. Eutrophication
 Pollution that results from excess
  nutrients in the ocean.
 Algae and plants overgrow due to
  presence of fertilizers and reduce the
  amount of nutrients available to plankton.
2. Plankton bloom
   Can deplete nutrients available for
    plants, algae and other plankton.
3. Sunlight

 All primary producers require sunlight to
  undergo photosynthesis.
 The amount of sunlight in the ocean
  varies due to depth, season and/or
  water clarity.
End of Notes Part 2!!!
III. Food Webs/Chains
Trophic Levels

   Representation of how energy
    transfers from one level to the
Primary Producers

 Base
 Autotrophs
 Examples: Algae, Plants and
Primary Consumers

 Heterotrophs
 Herbivores
 Most   important primary consumer-
Secondary Consumers

 Feed Primarily on Zooplankton
 Carnivores

 Lastlevel
 Bacteria and Fungi
Energy Flow

 Only about 10% of energy passes from
  one level to the next.
 Other 90% is used for work (repair,
  reproduction, etc).
Food Webs

 Represents the flow of energy through
  consumption in nature.
 Shows organisms have different
  choices of prey and eat across a trophic
  pyramids theoretical levels (a primary
  consumer can also be a secondary
Biological Magnification
 Small
  are increased as
  they go up a food
    – Remember the
       Biogeochemical Cycles

   Carbon-Oxygen Cycle
    – Photosynthesis & Cellular Respiration
   Water Cycle
    – Evaporation, Precipitation & Run-Off
   Nitrogen Cycle
    – Ammonia, Nitrosomonans, Nitrite,
      Nitrobacter & Nitrate
IV. Marine Lifestyles

   Plankton
    – Group of plants (phytoplankton) and animal
      (zooplankton) that exist adrift in ocean
    – Neuston
      • Plankton that float at the surface (i.e.:
        Portuguese man-of-war)
   Nekton
    – What you visualize when you think of
      marine organisms
    – Swim- small invertebrates to large whales
   Benthos
    – Live on or in the bottom
    – Motile or sessile
   3 groups
    – Eipfauna
       • Animals that live on the sea floor (crabs)
    – Epiflora
       • Plants that live on the sea floor (sea grasses)
    – Infauna
       • Partially or completely buried in the sea floor
         (clams, sand dollars, tubeworms)
   Deposit or Suspension Feeders
    – Deposit- Feed off detritus (loose organic
      and inorganic matter) drifting down from
    – Suspension- Filter particles (mostly
      plankton) suspended in water for food.
End of Notes
  Part 3!!
V. Ocean Zones

   Based on Light and Location
Division by Light
   Photic Layer (sunlight layer)
    – 2 areas
       • 1. Euphotic Zone (eu= good)
          –   Goes to about 660’.
          –   Enough light for photosynthesis
          –   Home to a variety of marine species
          –   Relatively warm temperatures
       • 2. Dysphotic Zone (dys= difficult)
          –   Nicknamed “Twilight Zone”
          –   Goes to about 3300’
          –   Insufficient light for photosynthesis
          –   Animals here must be able to handle cold
              temperatures, higher pressures, and darkness
   Aphotic Layer (midnight zone)
    – No sunlight therefore no plants
    – Can reach depths of close to 20,000’
    – Very cold and completely dark
    – Life isn’t easy here; fewer organisms than
      other zones
    – Some animals do not have eyes
Division by Location
   2 Major Divisions
    – 1. Pelagic Division
       • Pelagius= “of the sea”
       • Open water at any depth
       • 2 zones
    – 2. Benthic Division
       • Benthos=bottom (bottom of the sea floor)
       • Ocean bottom below neritic and pelagic zones
       • Nutrients get here by “raining” down from
         waters above (detritus)
Pelagic Division
1. Nertic zone (neritos= shallow)
    Intertidal Zone
     – Shoreline between high and low tides
     – High levels of light, nutrients, and oxygen
     – Stressful environment (drying, wave action)
    Subtidal Zone
     – Open Ocean
     – From shoreline to 650’
     – Organisms all floaters or swimmers
     – Large numbers of phytoplankton
2. Oceanic Zone

   4 areas
    – Epipelagic zone (epi= atop)
    – Mesopleagic (mesos= middle)
    – Bathypelagic (bathos= depth)
    – Abyssopelagic (a= without, byssos=
Benthic Division
6 Areas

   1. Supralittoral zone (supra= upper,
    – Water splashes but does not stay
    – Drying out and thermal stress are a
   2. Littoral zone (littoral= of shore)
    – The band of coast covered and uncovered
      by tidal action- the intertidal zone
Benthic Division cont.

    3. Sublittoral zone (sub= below)
     – Inner sublittoral- near shore
     – Outer sublittoral- ocean floor out to edge of
       continental shelf
    4. Bathyal zone
     – Seabed on the slopes and down to great
Benthic Division cont.

   5. Abyssal zone
    – Deep waters of the ocean
   6. Hadal zone (hades=underworld)
    – Deepest: trench walls and floors
End of Notes Part 4!!
VI. Marine Ecosystems

 Ecology- studies how organisms relate
  to each other and their environment
 Abiotic and Biotic Factors
    – Biotic- living (quantity and type of
    – Abiotic- non-living (temperature, wind, pH,
      currents, minerals, sunlight, etc).

   distinct entity usually with clearly
    defined physical boundaries, distinct
    abiotic conditions, an energy source,
    and a community of interacting
    organisms through which energy is
    transferred. (No ecosystem exists in
    isolation- therefore the ocean is
    composed of interacting ecosystems)
Ecosystem cont.

 Community- collection of different
  organisms living and interacting in an
  ecosystem. (Includes all species and
  types of organisms)
 Population- group of the same species
  living and interacting within a
Ecosystem cont.

 Habitat- includes the area and
  conditions in which you find an
 Microhabitat-exists on a very small
 Niche- organisms role in its habitat
    Ecosystems in the Open Sea
   Neutson ecosystem (plankton that live
    afloat on the sea surface)
    – Very thin layer (few mm)
    – Receives maximum amount of sunlight
    – Largest floating ecosystem- Sargasso Sea
      • Sargassum- brown algae accumulates in the
        middle of the North Atlantic as floating mats.
Ecosystems in the Open Sea
 Continental   Shelf
  – Rarely exceeds 656’; s nutrients are
    kept in the photic zone.
  – Highly productive ecosystem
Ecosystems in the Open Sea
 Upwelling
 –Significant to open sea
  ecosystems because they bring
  nutrients from deep water to
  shallow more productive depths
    Costal Ecosystems
   Estuaries
    – Exists where the tides meet rivers
    – Trap and accumulate runoff sediments, so
      they are rich with nutrients and biologically
    – Provide shallow sheltered water with a
      steady stream or nutrients
    – Serve as nurseries for 75% of commercial
      fish species
Costal Ecosystems cont.
   Salt Marshes
    – Exist in estuaries and along the coast
    – Halophytes- plants with adaptations that
      allow them to survive in salt water.
      • Have stomata on leaves that allow it to draw in
        oxygen into its submerged parts.
      • Sacrificial leaves that serve as a storage area
        for excess salt and fall of when the slat load
        reaches a certain point
      • Salt glands on leaves and stem excrete excess
    Costal Ecosystems cont.
   Mangrove Swamps
    – Various adaptations allow them to live in salt
       • Grow above waterline on stilt-like roots, which
         allows oxygen to reach the roots
    – Provide habitats for juvenile fish and
      invertebrates because of strong, tangled
    – Protect habitat and coasts from erosion
Costal Ecosystems cont.

   Sea grasses
    – Provide shelter
    – Internal salinity is the same as the sea
    – Reproduce by releasing pollen into
Costal Ecosystems cont.

   Intertidal zones
    – May be above waterline a times
    – Adaptations help retain moisture
Costal Ecosystems cont.
   Beaches
    – Rich and productive ecosystem
    – Acts a filter that processes compounds
      entering the sea
    – Sand protects coastline
      • Reduce sedimentation caused by costal erosion
    – Complex organisms live in submerged
      beach sand
    – Meiofauna
      • Benthic organisms that live in spaces between
        sand grains
Costal Ecosystems cont.

   Kelp and
    – Seaweed-red,
      green, and brown
    – Kelp forest- very
    Costal Ecosystems cont.

   Coral Reefs
    – Most productive ecosystem
    – Threats to coral reefs
      • Nutrients
      • Increased temperature is causing coral bleaching
        (Global Warming)
      • Competitive algae
      • Sedimentation
      • Coral Disease
End of Notes Part 5!!
    Polar Ecosystems
   The Arctic
    – Species found here have special adaptations
      • Anti-freezing compounds in blood
      • Low metabolism
    – Upwellings: Increased productivity because
      of nutrients being brought to the top
    – Challenges to marine organisms:
      • Reduced sunlight
      • Near freezing water
Polar Ecosystems cont.

   The Antarctic
    – Largest nutrient-rich area on Earth
    – Supports massive phytoplankton blooms
Deep-sea Ecosystems

   The Abyssal Zone
    – Average temperature 2C
    – No primary productivity (nutrients come
      from marine snow)
    – Greatest diversity found in the meiofauna
Deep-sea Ecosystems cont.

   Whale Falls
    – Place where dead whales come to rest on
      the deep ocean floor
Deep-sea Ecosystems cont.

   Hydrothermal
    Vents and Cold
    – Home to
Deep-sea Ecosystems cont.

   Hadal Depths- Ocean Trenches
    – Makes up the deepest ocean depths
    – Scientists know little because of limits of
       • Few submersibles have been built that can
         descend safely into the zone
       • 1 manned trip has been made to the deepest
         known spot in the ocean.
End of Notes Part 6!!

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