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Chapter 7
The Microbial World
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Copyright © 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

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Viruses
Infectious particle not made up of a cell:
Not capable of reproduction without a host cell
Structure:
Nucleic acid core – DNA or RNA
Capsid (protein coat) –
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Viruses
Common in the marine environment
Can infect marine bacteria, plankton, invertebrates, fishes, sea turtles, and mammals
ROLE: Lysis (bursting) of cells infected with viruses releases large amounts of dissolved organic matter (DOM) that can be used by other organisms
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4. Tiny Plankton Drift with ocean currents & waves, the ”wanderers”
Represents All kingdoms
Types:
Phytoplankton (photosynthetic algae)
Zooplankton (small animals)
Bacterioplankton (bacteria)
Meroplankton (larval stage of benthic & nektonic animals)
The 1st three are Holoplankton- ALWAYS plankton form

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Prokaryotes
Archaea:
Ancient organisms – fossils found that date 3.8 bya
*1st bacteria on Earth
They can tolerate wide ranges in temperature, salinity, and even desiccation (drying out).
Extremophiles Can be found in many “hostile” areas including near hydrothermal vents
Thermus aquaticus
Deinococcus radiodurans
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6. Prokaryotes Marine Bacteria:
Break down dead organic matter forming detritus, making them available as food for other organisms
Cyanobacteria -1st photosynthetic bacteria *gave us Oxygen on Earth
Most abundant Picoplankton (very small)
Single cell or colonial

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HOW THEY GET ENERGY
Metabolic diversity of Archaea and Bacteria:
Photosynthesis – derive energy from light
Chemosynthesis – derive energy from chemical compounds
Heterotrophs – derive energy from organic matter by means of respiration
Nitrogen fixation – converting gaseous nitrogen (N2) into ammonium (NH4+)
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8. 7.3 Unicellular Algae (Phytoplankton)
microscopic
Single celled
Color (green, brown, or red) results from photosynthetic pigments
Examples: algae, diatoms, dinoflagellates
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9. Phytoplankton Lives Matter
ROLES (add to notes)
They form an essential part of the marine food chain.
Regulate the amount of carbon in the atmosphere.

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Diatoms (add to chart)
Most efficient at photosynthesis
has frustule - cell wall made of silica, a (glass-like shell)
Produces oil (float)
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Marine Diatoms
They store excess energy as an oil that also aids in buoyancy.
Some produce a toxin, that can accumulate in the tissues or organisms that eat them such as shellfish and small fishes.
Larger organisms that eat these shellfish or fishes can become ill or die from the accumulated toxin.
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12. Why we like dead diatoms (Diatomaceous Earth)
Used in filters
Clarifying beer
Temperature and sound insulators
Mild abrasives in toothpaste
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13. Dinoflagellates (add to chart)
Two flagella for motion
Migrate up during sunlight portion of day
Migrate down at night for protection
Cell wall Made of cellulose.
Some are bioluminescent
Rapidly reproduce
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Algal Blooms
Diatoms and dinoflagellates can go through periods of rapid growth known as blooms.
Causes red tides when conditions right (nutrients)
Can create a Harmful algal bloom (HAB)
Some produce strong neurotoxins which are harmful to marine animals (death) and humans (respiratory)
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15. Marine Dinoflagellates (add to chart)
Zooxanthellae are important dinoflagellates that live in a symbiotic relationship with reef corals, some sea anemones, and other organisms.
Many of these host organisms can’t grow without zooxanthellae.
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16. Other Unicellular Algae (add to chart)
Coccolithophorids
photosynthetic
spherical cells
calcium carbonate plates
Fossils in chalk sediments
White Cliffs of Dover
Emiliania huxleyi
This Photo by Unknown Author is licensed under CC BY-SA
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Fungi (add to chart)
Cell wall cellulose or chitin
Decomposers
Cause diseases
symbiotic with cyanobacteria to form lichens
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18. Protozoans (add to chart)
Foraminiferans :
heterotrophs, animal-like
Shells of calcium carbonate
important contributors of calcareous material on coral reefs or sandy beaches.
Have test (shell) made of CaCO3
Have Pseudopods (false feet) extend through pores in the shell where they capture food particles
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Protozoans
Ciliates:
Hair-like cilia for locomotion and feeding
Most live as solitary cells.
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21. Most Important Characteristics of Marine Microbes
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