Taxonomic Classification In the ocean hardly represented ...oceanography.asu.edu/Oc_Nov21_pos.pdf · Classification of marine organisms according to habitat and mobility Marine organisms
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Taxonomic ClassificationTaxonomic Classificationof Organismsof Organisms
• 3 domains of life:–Archaea–Bacteria–Eukarya
Figure 13-1
In the oceanIn the oceanhardly represented.hardly represented.
Only in coastalOnly in coastalocean, mangroves ocean, mangroves and swamps and swamps (eelgrass, (eelgrass, surfgrasssurfgrass), ), and salt marshes.and salt marshes.
Classification of marine organisms according to habitat
and mobilityMarine organisms can be classified into
one of three groups based on habitat and mobility:
1. Plankton (floaters)• Phytoplankton (drifting algae)• Zooplankton (drifting phagotrophic protists and
animals)• Bacterioplankton, Archaea (marine prokaryotes
either free floating or attached)
2. Nekton (swimmers)3. Benthos (bottom dwellers)
Metabolic Classification
• Depending on Carbon source used: heterotrophic vs autotrophic
• Depending on the Energy source:Chemosynthesis, Photosynthesis, Respiration, Fermentation
See Handout!
Classification according to size
Picoplankton (see last handout) is the group with the smallest cells, measuring anywhere from 0.2 – 2 µm (1 µm = 10-3 mm or 10-6 m).
Nanoplankton measures from 2-20 µm.
Microplankton measures from 20-200 µm (= 0.2 mm)
Mesoplankton measures from 200-2000 µm (= 2 mm)
Macroplankton is larger than 2 mm –20 mm (= 2 cm)
Megaplankton is larger than 2 cm
Classification according to developmental stages
• E.g., squid experience benthic, planktonic, and nektonic stages
• Squid are considered meroplankton(opposite = holoplankton)
Classification of marine organisms according to habitat
and mobilityMarine organisms can be classified into
one of three groups based on habitat and mobility:
1. Plankton (floaters)• Phytoplankton (drifting algae)• Zooplankton (drifting phagotrophic protists and
animals)• Bacterioplankton, Archaea (marine prokaryotes
either free floating or attached)
2. Nekton (swimmers)3. Benthos (bottom dwellers)
Phytoplankton(examples)
– Diatoms (Phylum Chrysophyta, Class Bacillariophyceae)
• silica test resembles a pillbox– Coccolithophorids (Phylum Chrysophyta, Class
Prymnesiophyceae)• calcite plates form a spherical test
– Dinoflagellates (Phylum Pyrrhophyta)• Produce a test made of cellulose• Posses a whip-like flagella• Bioluminescence (biological production of light by
organisms)• Exist in great abundance, creating red tides (harmful
algae blooms)
Diatoms and dinoflagellates
15-4
Diatom life cycle Coccolithophorids: The most abundant eukaryotes on Earth
A vast bloom of Trichodesmium visible fromspace - Photo NASA.
Tufts of Trichodesmium
Cyanobacteria
Trichodesmium floats on the surface of tropical/subtropical oceans and is one of the most important nitrogen fixers in the ocean.
Very small phytoplankton(picoplankton and nanoplankton) are the most important group of phytoplankton in the open ocean.
They can only be visualized by high magnification in the microscope.
The glow of these cells (Synechococcus)comes from the fluorescence of theirphotosynthetic pigments(epifluorescence microscopy).
Single celled cyanobacteria
Classification of marine organisms according to habitat
and mobilityMarine organisms can be classified into
one of three groups based on habitat and mobility:
1. Plankton (floaters)• Phytoplankton (drifting algae)• Zooplankton (drifting phagotrophic protists and
animals)• Bacterioplankton, Archaea (marine prokaryotes
either free floating or attached)
2. Nekton (swimmers)3. Benthos (bottom dwellers)
© Springer-Verlag 2002
Natural diets of vertically migrating zooplankton in theSargasso Sea
A. Schnetzer1, 2, and D. K. Steinberg1, 3
Ciliates:Phagotrophic protists that feed on bacteria, and other pico- and nanoplankton
heterotrophic dinoflagellate: Noctiluca Radiolaria and Foraminifera
Some microzooplankton (phagotrophic protists) Meso-zooplankton: Copepods
• Copepods are planktoniccrustacea.
• They filter phytoplankton out of the water
• They have a hard exoskeleton and a segmented body with jointed legs
Figure 15-5
Macro-zooplankton : Krill (Euphausiids)
• Krill are related to copepods but are larger in size
• Abundant in Antarctic waters, where they are a favorite food of the largest whales
Figure 15-6
Megaplankton : Salps(planktonic tunicates) Megaplankton : Cnidarians
• Cnidarians are soft-bodied organisms including:– Hydrozoans:
Siphonophores(Portuguese man-of war)
– Scyphozoans (jellyfish)
Figure 15-7
With the advent of diving missions, researchers such as Bruce Robison are uncovering the secret watery world of jellies — some, for instance, dine on jelly themselves.
Back home: some crustaceans, such as this amphipod, settle down and raise their young atop a jelly.
Depth charge: Shinkai 6500 gives researchers a rare glimpse of the deep ocean's delicate jellies.
Jelly fishJelly fish((ScyphozoaScyphozoa))
Nature Nature 426426, 12 , 12 -- 14 ( 2003)14 ( 2003)
Classification of marine organisms according to habitat
and mobilityMarine organisms can be classified into
one of three groups based on habitat and mobility:
1. Plankton (floaters)• Phytoplankton (drifting algae)• Zooplankton (drifting phagotrophic protists and
animals)• Bacterioplankton, Archaea (marine prokaryotes
either free floating or attached)
2. Nekton (swimmers)3. Benthos (bottom dwellers)
© Springer-Verlag 2002
Natural diets of vertically migrating zooplankton in theSargasso Sea
A. Schnetzer1, 2, and D. K. Steinberg1, 3
Bacteria that float in the ocean (single cells, in aggregates, detritus).Most are very small (avg. 0.5 µm) and are heterotrophic (respire dissolved organic substances).
Bacterioplankton:
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