1. Chapter 5
Microbes

2. Viruses Viruses in the Marine Community:
They are common in marine waters
They can infect bacteria, plankton, fish, sea turtles and marine mammals
Lysis (bursting) of viral infected cells spills contents and releases large amounts of organic matter that can be utilized by other organisms (dissolved organic matter or DOM)

3. Prokaryotes Archea and Bacteria Prokaryotic- no nucleus
Single chromosome (normally circular)- some also with plasmids
Most with cell wall
Great metabolic diversity

4. Prokaryotes Archea – Widely distributed in the marine community
They can tolerate wide ranges in temperature, salinity and even desiccation (drying out)
Can be found in many areas including near hydrothermal vents and salt flats (two very extreme environments)

5. Special Features of Bacteria:
One of the most important jobs of bacteria in the marine community is to break down dead organic matter – this forms detritus, which are minute particles of organic matter now available as nutrition for other organisms

6. Diatoms Diatoms: Photosynthetic
Yellow-brown color in life is a result of photosynthetic pigments, chlorophyll A and C and carotenoids
Shell of silica called a frustule
Most important primary producer on Earth
Mostly solitary and unicellular
Some can form colonies

7. Most are planktonic
Some produce a toxin, known as domoic acid, that can accumulate in the tissues or organisms that eat diatoms such as shellfish and small fish
Larger organisms that eat these shellfish or small fish can become ill or die from this accumulated toxin

8. Mainly reproduce by cellular division
Due to this, diatoms get smaller each time they reproduce
To restore normal size, they must sexual reproduce

10. Dinoflagellates Dinoflagellates
Most species live in marine environment
Mostly photosynthetic, some can ingest particles
Two flagella
Also reproduce by cellular division
Some are bioluminescent

11. Dinoflagellates
Dinoflagellates
Zooxanthellae are important dinoflagellates that live in a symbiotic relationship with corals, sea anemones and other organisms

12. Algal Blooms
Dinoflagellates can go through periods of rapid growth known as “blooms”
Result of high levels of nutrients in the water
Can be harmful to marine organisms and even people at times
Called “Red Tides”

13. Pfiesteria is a dinoflagellate that produces very serious toxins that can cause massive fish kills, harm shellfish and impair the nervous system in humans.
Pfiesteria was discovered near the Outer Banks in North Carolina

14. Protozoa Foraminiferans (forams) Found on sandy or rocky bottoms
Shells of calcium carbonate
Can be important contributors of calcareous material on coral reefs or sandy beaches
Pseudopods (false feet) extend through pores in the shell where they are used to capture minute food particles such as phytoplankton

15. Protozoa Radiolarians
Planktonic, mostly microscopic, although a few can reach large sizes
Shell of silica
Like forams, they use pseudopods.

17. Protozoa Ciliates Cilia present for locomotion
Most live as solitary cells
Some build shells made of organic debris
May live on hard substrate
Some are planktonic

19. Fungi Eukaryotic and mostly multicellular Heterotrophic
Most of the 1500 species of marine fungi are microscopic

20. Fungi
Like bacteria, many fungus break down dead organic matter into detritus
Some fungus live in symbiosis with cyanobacteria, these are known as lichens
Marine lichens often live in wave-splashed areas of rocky shorelines and other hard substrate