Chapter 6 Marine MicrobesPlankton

(organisms invisible to the naked eye)

• 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 microscope1. Diatoms2. Dinoflagellates3. Forams4. Euglena5. Volvox

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.

Diatom Structure• Bilaterally symmetrical• Glassy Cell wall• 2 valves- 1 large, 1 small• Visible geometrically shaped pattern-(helps

distinguish between species)

Reproduction• Reproduction: –Asexually by

fission• When cells divides,

each daughter gets one of the 2 valves• Eventually daughter

that inherited smaller valve will reproduces sexually

• Digestion: – Makes own food

(autotroph) via photosynthesis

• Level of organization:– Unicellular and

eukaryotic

• Ecological Role– Responsible for ~50% of

oceans energy production

– Producers

Dinoflagellates- structure

• Globular, single-celled organisms

• 2 flagella that lie in groves on the center of surface

• Larger of phytoplankton

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?

• 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.

Goodby’s Creek in Mandarin during last Algae Bloom

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

Foram Reproduction

• Asexual fission most species

• Sexual reproduction-some species

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

Ecological Role

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

• http://www.youtube.com/watch?v=Fpry23bS6g0&safety_mode=true&persist_safety_mode=1&safe=active

Ever wonder about that green gunk?

• Its Euglena! – Possess chlorophyll, 1 or

2 flagella

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

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

Euglena: Ecological Role

• Photosynthesizer • Acts as food for

other protists and fish

• http://www.youtube.com/watch?v=4MlR3dKfXmc&feature=related&safety_mode=true&persist_safety_mode=1&safe=active

•

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

Volvox ReproductionAsexual• Gonadia near the posterior

– Divide numerous times to produce new colonies

– Genetically identical to the parent

– Mitosis

Sexual

• Male colonies release sperm into water column

• Female colonies’ individual cells enlarge to become eggs

• Offspring different from parents– Meiosis

Volvox Digestion

• Producer• Makes energy via

photosynthesis

Volvox Ecological Role

• Primary producers in freshwater ecosystems– Lakes, ponds, ditches

• Model science organism for cell death and regrowth

• Some parasites feed off Volvox

Volvox

• http://www.youtube.com/watch?v=He9FSeGRi3A&safety_mode=true&persist_safety_mode=1&safe=active

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)