Phytoplankton

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Phytoplankton

• September 25, 2007

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Marine Plants

• Prokaryotes
• Archaea
• Bacteria
• Heterotrophic Bacteria
• Autotrophic Bacteria
• Cyanobacteria
• Eukaryotes
• Unicellular Eukaryotes
• Multicellular Eukaryotes
• Multicellular Algae (Seaweeds)
• True Marine Plants

Phytoplankton
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Archaea

• Look similar to bacteria - were only recently
  classified separately
• Decomposers
• Live in extreme environments

http//www.ucmp.berkeley.edu/archaea/archaeamm.htm
l
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Bacteria

• All prokaryotes and unicellular
• Very small, most less than 1 ?m
• Found everywhere
• Very abundant - 106 bacteria/ml

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Bacteria

• Heterotrophic Bacteria
• Decomposers
• Recycle Nutrients
• Autotrophic Bacteria
• Chemosynthetic Bacteria
• Cyanobacteria

http//www.microscopy-uk.org.uk/mag/imagsmall/bact
eria2.jpg
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Cyanobacteria

• Prokaryotic primary producers
• The smallest, simplest phytoplankton
• Major Types
• Prochlorococcus
• Synechococcus
• Nitrogen Fixers (Trichodesmium)

http//scrippsnews.ucsd.edu/pressreleases/images/c
ell.jpg
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Cyanobacteria

• What are the advantages and disadvantages to
  being small as phytoplankton?
• Where would cyanobacteria thrive in the ocean?

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Eukaryotic Phytoplankton

• Unicellular
• Chloroplasts
• Evolved from endosymbiosis
• Major Types
• Diatoms
• Dinoflagellates
• Coccolithophores
• Others

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Diatoms

• Vary in size from a few ?m to over 1mm
• Very important in coastal and other upwelling
  regions - form large blooms
• Many form chains
• Cell enclosed by a silica frustule (test)

http//oceanandair.coas.oregonstate.edu/images/use
rimages/StudentsInTheField/diatoms_noaa_239x157.jp
g
http//thalassa.gso.uri.edu/ESphyto/sizeshap/shape
.htm
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Diatoms

• Silica Frustule
• Upper and lower frustules join like a pillbox
• 2 major shapes - pennate or centric
• Perforated
• Often ornamented with spines

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Diatom Reproduction

• Explosive population growth

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Diatoms

• Where and would we expect to find blooms of
  diatoms?
• How would an abundance of diatoms affect a marine
  ecosystem?

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Dinoflagellates

• Motile
• Have 2 flagella (one longitudinal and one
  transverse)
• What advantages are there to being motile?

http//webs.lander.edu/rsfox/rsfoximages1/protozoa
143L_x550_x_289x.gif
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Dinoflagellates

• Can be autotrophic, heterotrophic, or mixotrophic
• Some have a test known as a theca

http//www.palaeos.org/Dinoflagellata
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Dinoflagellates

• Some can form blooms known as red tides
• Some bloom-forming dinoflagellates can be toxic
• What are the effects of these harmful algal
  blooms?
• Shellfish poisoning
• Fish kill
• Hypoxia

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Coccolithophores

• Typically smaller than diatoms and
  dinoflagellages
• Have calcium carbonate (CaCO3) tests made up of
  many coccoliths
• Can form large blooms
• Tests are preserved in sediments

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Big vs. Small Phytoplankton

• Big
• Defense against predators
• Fast growth when conditions are right
• Small
• Slow Sinking
• High Surface AreaVolume Ratio for Nutrient
  Uptake

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Why are phytoplankton important?

• Responsible for 50 of global photosynthesis
• Are the base of the oceanic food web
• Provide much of the worlds oxygen
• Sink for atmospheric carbon dioxide
• Regulate global climate

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Primary Productivity

• What limits primary productivity at different
  depths?

http//content.cdlib.org/xtf/view?docIdkt167nb66r
chunk.id0doc.viewprint
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Primary Productivity
Desiderio et al., Jounral of Atmospheric and
Oceanic Technology., 1993.
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Primary Productivity

• What limits primary productivity at different
  times of the year?

Thurman and Burton, (2001) Introductory
Oceanography., pg. 405
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Primary Productivity