Marine Food Webs

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Marine Food Webs

• A complex ecosystem

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Introduction to Ecosystems

• Producers turn the suns energy into usable
  energy for consumers.

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• Consumers will feed on producers or other
  consumers for energy

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• Decomposers will feed on producers or consumers
  when they die and return nutrients to the system
  for producers to use. (bacteria, fungi)

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Symbiotic Relationships

• There are three types of symbiotic relationships
  that can exist between two organisms
• Mutualism
• Both organisms benefit from the relationship
  - clownfish and coral or sea anemones.

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Commensalism

• One organism benefits and the other is unaffected
  (neither harmed or helped).
• Barnacles
• on whales
• or crabs

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Parasitism

• One organism (the parasite) benefits from the
  host, and the host is harmed. Ascaris worm in
  codfish
• Sea lice on Atlantic Salmon

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• A trophic level is the level at which a
  particular organism feeds in the ecosystem.
• Energy and biomass is lost at each level as about
  90 of an organisms energy goes into its daily
  life processes and is not passed on.

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• The ocean is divided into 3 categories
• Plankton Usually very small floating organisms,
  either plants or animals, which are at the mercy
  of the tides winds and currents.
• Nekton Strong swimming animals that live in the
  open ocean, and are not affected by tides or
  currents.
• Benthos Organisms that live on or in the ocean
  floor could be plants or animal

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Plankton

• These feeble swimming plants or animals are
  separated into phytoplankton (plants), which are
  producers, or zooplankton (animals) which are
  first order consumers

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Plankton

• Phytoplankton are mainly diatoms which are the
  most important food source in the ocean, usually
  single celled plants (algae). They are called
  diatoms because of their (silica) shell symmetry
  designed to help them float.

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A marine food web
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Plankton

• Dinoflagellates represent both plants and
  animals they are the second most important food
  source in the ocean. They are often responsible
  for shellfish becoming toxic (red tide) if they
  have an outbreak.
• The rhodophyta
• red algae - can
• contain a toxin.

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Zooplankton

• This is the animal form of plankton. If their
  entire life is in this form they are called
  holoplankton and if they are only in this form
  for part of their life cycle they are called
  meroplankton

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Zooplankton

• These animals come in different sizes and are
  grouped into four categories
• nanoplankton microscopic/unicellular
• microplankton usually eggs and larval stage
• macroplankton usually about 1mm, copepods
• megaplankton- mostly jellyfish.

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Nekton

• Nekton consists of all animals that are capable
  of swimming powerfully, mammals, reptiles,
  sharks, and fish. Squid are the only
  non-vertebrate that is a strong enough swimmer to
  be in this category.

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Nekton

• Although many of these animals adapted to
  swimming great distances, they usually remain
  close to one area because they have not adapted
  to all environmental changes in the ocean.

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Benthos

• The benthic zone consists of plants (epiflora)
  and animals (epifauna) on or in the bottom. Some
  of these organisms are the sea fan, sponges,
  coral, crabs mussels, and sea weed.

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Benthos

• Animals that are buried in the ocean floor like
  clams and worms are called infauna.

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Benthos

• The larval stage of many benthic animals is an
  extremely important part of the meroplankton,
  thus a very valuable food source for the ocean.

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Conclusion

• The marine biome is divided into four main parts
• 1) Planktonic Zone The top few metres of the
  ocean where plankton live.
• 2) Nektonic Zone The open ocean where the
  inhabitants can swim to the surface or the bottom
  and are called nekton.

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• 3) Benthic Zone This is the floor of the ocean
  where the inhabitants are usually fixed to the
  bottom or sessile like coral. Some (like lobster
  or crabs) are mobile.
• 4) Intertidal Zone Organisms here are covered
  by water at high tide and are exposed to air
  during low tide. Many organisms here are adapted
  to living on land and under water.