Dinoflagellates

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Dinoflagellates

• Dinoflagellates
• Possess 2 flagella
• Cell wall composed of cellulose
• Autotrophic and heterotrophic abilities
• Some ability to migrate vertically in response to
  sunlight
• Bioluminescence
• Harmful algal blooms

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Coccolithophorids

• Calcium carbonate plates (coccoliths) cover the
  cell
• Blooms are visible from space
• As cells grow, coccoliths shed and sink to the
  bottom

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Prasinophytes-a type of green algae

• Eukaryotes related to land plants
• Store starch and have chlorophyll
• The smallest known eukaryotic cell is
  Ostreococcus (Left)
• Another important small cell is Micromonas
  (right)
• Found in open ocean and near shore

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Zooplankton

• Two general categories of plankton
• Holoplankton spend their entire lives as
  plankton
• Meroplankton includes eggs, larvae, and
  juveniles of many species that are only plankton
  for a portion of their lives

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• The Holoplankton
• spend their entire lives as plankton

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Zooplankton

• Herbivores, carnivores, or omnivores
• Some ability to swim, vertical migration
• Rapid growth rate and short lifespan ? rapid
  liberation of nutrients
• Patchiness of population density

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• Most well studied and widespread groups are the
  crustaceans
• Copepods
• Herbivorous
• Link between photoplankton and first level
  carnovours

Rapid swimming in a series of jumps
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• Euphausiids (Krill)
• Omnivores
• Occur in huge quantities near Antarctica where
  highest abundance of photoplankton are found.
• Main food for Baleen whales
• Up to 1.35 billion tons
• Iodine content too high for human consumption
• Harvested for animal feed.

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• Other important zooplankton include
• Chaetognaths
• Foraminifera and radiolarians
• Tintinnids
• Pteropods
• Ctenophores
• Salps
• Cnidarians

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Chaetognaths (Arrow worms)

• Voracious planktonic predators
• First level carnivores
• Abundant from surface to great depths
• Species are specific to water masses
• Sagitta setosa North Sea water
• Sagitta elegans Only in Oceanic waters

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Foraminiferans, Radiolarians, Tintinnids

• Microscopic single celled amoeba-like protozoans
• Feed on phytoplankton and some zooplankton
• Forams encased in a calcareous covering
• Radiolarians encased in a silica test or shell
• Both found in warmer waters
• Upon death, shells settle to the bottom
• Forams in shallow water (Foraminiferan ooze)
• Radiolarians in deeper water (Radiolarian ooze)
  below 13,200 feet. Silica resists dissolving
  action
• Tintinnids found in coastal waters

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Ctenophores

• Comb jellies, sea walnuts, sea gooseberries
• Transparent, gelatinous, bioluminescent
• Float in surface waters
• All are carnivores

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Pteropods

• Mollusks
• Holoplanktonic
• Related to snails
• Some are carnivores, others are herbivores
• Upon death, shells settle to the bottom and form
  Pteropod Oozes.

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Salps

• Pelagic tunicates-related to chordates
• A group of underwater saclike filter feeders
• Feed on phytoplankton
• Live in a gelatinous walnut size house