Chapter 6 Marine Microbes Plankton(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 microscope 1. Diatoms 2. Dinoflagellates 3. Forams 4. Euglena 5. 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.
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
• 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
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
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 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
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
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)