1. Chapter 6 Marine Microbes
Plankton
(organisms invisible to the naked eye)

2. • Include viruses, one-celled organisms, and fungi.
• Microbes play many different roles in marine ecosystem.
• Phytoplankton-planktonic algae
• Zooplankton-larvae of small animals-ex fish, jellyfish
• We will discuss 3 of these in detail that you will be
accountable for and be able to identify under a
microscope
1. Diatoms
2. Dinoflagellates
3. Forams
4. Euglena
5. Volvox

3. Diatoms Characteristics
• Most distinctive of plankton samples
– Most common
• Low latitudes-occur in coastal waters
• Phytoplankton-Contributed to most of
primary productivity of an area.

4. Diatom Structure
• Bilaterally symmetrical
• Glassy Cell wall
• 2 valves- 1 large, 1 small
• Visible geometrically shaped pattern-(helps
distinguish between species)

5. Reproduction
• Reproduction: • Digestion:
– Asexually by – Makes own food
fission (autotroph) via
photosynthesis
• When cells divides,
each daughter gets
one of the 2 valves
• Eventually daughter
that inherited smaller
valve will reproduces
sexually

7. • Level of organization:
– Unicellular and
eukaryotic
• Ecological Role
– Responsible for ~50% of
oceans energy
production
– Producers

8. Dinoflagellates- structure
• Globular, single-celled
organisms
• 2 flagella that lie in
groves on the center of
surface
• Larger of phytoplankton

9. Reproduction
• Asexually by fission
– Split cell into two
– Can happen at a rate of one division per day
• Sexual in some species by gametes
• If you had two species of Dinoflagellates and
species A produced asexually while species B
produced sexually, which species to you expect to
survive throughout time longer and why?

10. • Ecological Role: Some species
are responsible for Red Tide
– algae bloom-large quick
population boom
– Produce toxins, usually cannot
eat fish during this time
– http://www.youtube.com/watch
?v=auEePWRqj7Y&safety_mode
=true&persist_safety_mode=1&
safe=active
• Example (back side of Study
Guide) Zooxanthellae are
collections of dinoflagellates
– They lack flagella like most
species
– Mutualistic relationships with
corals, jellyfish, and mollusks.

11. Goodby’s Creek in Mandarin during last Algae Bloom

13. Forams Characteristics and
Structure
• Have a pseudopod-organelle that is an
extension of the cell surface
– Used for locomotion and food capture
• Have a shell
• deep as Marianas Trench
• members of zooplankton

14. Foram Reproduction
• Asexual fission most
species
• Sexual reproduction-
some species

15. Forams: digestion/energy
• Consume a lot of
diatoms and
dinoflagellates
• Some host green/red
algae
– Symbiotic relationship
• Forams get nutrients
• Coral reefs get calcium
carbonate

16. Ecological Role
• Food for fish and invertebrates (inverts)
• Turn over nutrients in the ocean
• Most abundant group of fossils
– Make up sediments

17. • http://www.youtube.com/watch?v=Fpry23bS
6g0&safety_mode=true&persist_safety_mode
=1&safe=active

18. Ever wonder about that green
gunk?
• Its Euglena!
– Possess chlorophyll, 1 or
2 flagella

19. Euglena
• Salt or fresh water
• Digestion- perform
photosynthesis or absorb
nutrients
– stigma at base of flagella
allows euglena to orient
themselves towards a light
source
• Reproduce using binary
fission
– Split into two new
organisms

20. Euglena Structure (draw sketch
on back side of Study Guide)

21. Euglena: Ecological Role
• Photosynthesizer
• Acts as food for
other protists and
fish

22. • http://www.youtube.com/watch?v=4MlR3dKf
Xmc&feature=related&safety_mode=true&per
sist_safety_mode=1&safe=active
•

23. Volvox
• Structure:
– Individual cells form
colonies (level of
organization=
multicellular) up to
50,000 cells!!!!- cannot
live alone
– Eyespots that allow
them to swim near light
– Flagellates –locomotion
• Similar to Euglena

24. Volvox Reproduction
Asexual Sexual
• Gonadia near the posterior
– Divide numerous times to
• Male colonies release
produce new colonies sperm into water column
– Genetically identical to the • Female colonies’ individual
parent cells enlarge to become
– Mitosis eggs
• Offspring different from
parents
– Meiosis

25. Volvox Digestion
• Producer
• Makes energy via
photosynthesis

26. Volvox Ecological Role
• Primary producers in
freshwater ecosystems
– Lakes, ponds, ditches
• Model science organism
for cell death and
regrowth
• Some parasites feed off
Volvox

27. Volvox
• http://www.youtube.com/watch?v=He9FSeGR
i3A&safety_mode=true&persist_safety_mode
=1&safe=active

28. Independent Work Time
• Finish back side of your study guide and turn
in.
– Study Guides will count as a homework/classwork
assignment for Session 3
• You can find more information in Chapter 6
(blue MARINE BIOLOGY class set books)