Download Chapter 2 Phytoplankton

Phytoplankton
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The phytoplankton - principal source of primary nutrition
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Produces organic matter through photosynthesis
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Contribute to about 95% of primary production in the oceans and supports the
secondary production (zooplankton) and tertiary production (fish, shellfish,
mammals, etc.)
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About 5,000 phytoplankton have been identified in aquatic ecosystem
Diatoms
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Common forms of centric diatoms are Coscinodiscus, Chaetoceros, Biddulphia,
Skeletonemia, Thallassionema, and Bacteriastrum, Thalassiosira, Navicula,
Triceratium
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Some common pennate diatoms are Pleurosigma, Gyrosigma, Rhizosolenia,
Thalassiothrix, Thalassionema and Nitzschia
Dinoflagellates
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Are next to diatoms
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Abundant in trophical water producing red tides
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The genera of Peridinium and Ceratium are most commen in the plankton
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Common unarmored (“naked”) representatives
Gymnodinium, Cystidinium, and Glenodinium
of
dinoflagellates
are
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Common armored dinoflagellate species are Peridinium, Ceratium, Dinophysis, and
Goniaulax etc.
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Non-photosynthetic species - Noctiluca. Sp.
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Certain species produce a poison – PSP
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Red tide is by Goniaulax sp. and Gymnodinium brevis. Noctiluca scintillans exhibit
bioluminescence
Coccolithophores
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Are one-celled marine plants that live in large numbers in the upper layers of the
ocean
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Abundant in the sub-trophical areas and also live in most subpolar regions.
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Importatent forms - Dicrateria, Phaeocystis, Coccolithus, Prymnesium etc.
Silicoflagallates
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Phytoflagellates are algae
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Abundant in phytoplankton
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Important forms are Dictyoche, Distephanus, Chromulina etc.
Blue-green algae
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Are the hard, simple algae
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Chief primary producers of organic matter
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Trichodesmium sp species are tropical, dominant in warm seas and forms blooms
Trichodesmium sp
Green algae
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The green algae are unicellular and colonial flagellates, often colonial, commonly
found in fresh water.
ZOOPLANKTON
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Are heterotrophic plankton except bacteria and viruses
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Size range from 2 µm (flagellates) to several meters (jellyfish)
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Adaptation to a pelagic mode of existence – holoplankton
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Larval forms present temporarily in the plankton are called meroplankton
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The holoplankton includes – foraminiferans, radiolarians, siphonophores,
ctenophores, pelagic polychaetes, copepods, cladocerans euphausids,
chaetognaths, pteropods, salps etc.
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Whereas meropkankton - the drifting larval stages of numerous littoral and benthic
species such as polychaetes, barnacles, decapods crustaceans, echinoderms,
molluscs etc.
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Fish eggs and fish larvae - ichthyoplankton