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The Microbial World Chapter 5 Prokaryotic Metabolism • Autotrophs • Heterotrophs Autotrophs • Some bacteria and archaea make their own organic compounds – Primary producers – If they do photosynthesis it takes place in on folded membranes in the bacteria cell • Photosynthetic bacteria account for much of the primary production of open ocean • Other bacterial autotrophs- chemosynthetic bacteria Heterotrophs • Most marine bacteria are heterotrophs • Heterotrophs obtain energy from organic matter by respiration • Respiration in aerobic bacteria and archaea use oxygen • In Anoxic sediments bacteria use anaerobic respiration Nitrogen Fixation • Bottom dwelling and planktonic cyanobacteria carry out nitrogen fixation • Nitrogen fixation N2 NH4 (covert nitrogen to ammonium) • Ammonium is then transferred into NO3- (nitrate) and other N compounds – These N sources can be used by primary producers Unicellular Algae • Algae – very diverse group (mostly aquatic, mostly photosynthetic) • Eukaryotic- cells have a nucleus, organelles • Photosynthesis- Chloroplast • Lack true leaves, stems, roots • Have plant and animal characteristics- Protista Diatoms • Unicellular but they can be colonial or form groups or chains • In a shell made of silica frustule (2 halves) • The perforations allow dissolved gases and nutrients to enter and exit • Coloration- carotenoid pigments (few are colorless) • Photosynthetic factories • Some are toxic Diatom Reproduction • Asexual reproduction • Auxospores- resistant stages that eventually give rise to larger cells that display the frustule characteristic of the species **get smaller each division** • Favorable conditions- bloom • Diatomaceous ooze- dead diatoms sink and form thick deposits of siliceous material Dinoflagellates • Large group of planktonic unicellular organisms • 2 flagella, cell wall, plates • Photosynthesize and ingest • Reproduction is almost exclusively by cell division • Bioluminescence • Toxic Protozoans (animal like protists) • • • • Eukaryotic Structure is simple Animal like Protozoans comprise several groups of unrelated origins • Heterotrophs and some photosynthesize Foraminiferans • • • • Type of marine protozoan Have a shell (test) made of CaCO3 Pseudopodia- extensions of the cytoplasm Live on the bottom either free or attached – Shells of bottom forams are important contributors to calcarious material • White cliffs of Dover Radiolarians • Planktonic marine protozoans • Secrete shells of glass and other materials • Typical shells are spherical with radiating spines • Sausage shaped colonies • When they die and sink to the bottom they become silicious ooze – Resistant to dissolving under pressure Ciliates • Protozoans • Lots of hair like extentions – Locomotion and feeding • Found all over seaweeds and in bottom sediments • Live in gills of clams, urchin intestines,skin of fish Fungi • Eukaryotic and mostly multicellular – Molds, yeasts are unicellular • They are heterotrophs that lack chloroplasts • 500 species of marine fungi (most are microscopic) • Decompose detritus • Some are parasites • Some form symbiotic relationships with algae – lichens Microbial world Prokaryotes • Bacteria – Cyanobacteria (stromatolites) • Archaea – Extremophiles Eukaryotes • Diatoms • Dinoflagellates • Protozoans (animal like) – Foraminierans – Radiolarians • Fungi Presentation • • • • • • Table 1 –Diatoms Table 2- Dinoflagellates Table 3- Foraminiferans Table 4- Radiolarians Table 5- Ciliates Table 6- Fungi Poster Rubric • • • • Image Definition At least 5 facts Importance to marine environment/role in marine environment • ** this will be a graded assignment** • If you finish early complete your sponge reading and question sheet until we start presenting
