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Microbes In Aquatic Marine Ecosystem

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Microbes In Aquatic Marine Ecosystem

  1. 1. Microbes in Aquatic Marine Ecosystems Joemar C. Taganna MS Microbiology
  2. 2. Introduction <ul><li>The oceans and seas: The largest aquatic system, covering 70% of the earth’s surface </li></ul><ul><li>Includes oceans, estuaries, salt marshes, lagoons, tropical communities, rocky subtidal and intertidal ecosystems </li></ul><ul><li>Home to a host of different species ranging from tiny microbes to huge mammals </li></ul>
  3. 3. Introduction (cont.) <ul><li>While microbes are not visible, they account for more than 90% of ocean biomass and constitute a hidden majority of life that flourishes in the sea </li></ul><ul><li>But much of this microbial life is still unknown because of difficulties in growing them in a culture and in observing them in nature </li></ul>
  4. 4. Introduction (cont.) <ul><li>Differ from freshwater environments in many ways (salinity, average temperature and nutrient status) </li></ul><ul><li>Nutrient levels in the open ocean are often limiting, specially N, P and Fe </li></ul><ul><li>But still, the collective photosynthesis and O 2 production here are major factors that affect many ecological systems on Earth </li></ul>
  5. 5. Chlorophyll in the oceans and vegetation on land throughout the world. Source: The SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE
  6. 6. The Inshore and Open Ocean Microbiology <ul><li>Inshore ocean areas: More dense than open ocean areas since it is more nutritionally fertile </li></ul><ul><li>Denser populations can be found in marine bays and inlets that receive high levels of nutrients from sewage or industrial waste runoff </li></ul>
  7. 7. <ul><li>In severe pollution, shallow marine water can become anoxic from the consumption of O2 by bacteria </li></ul><ul><li>And also, the water become toxic due to the production of H2S by sulfate-reducing bacteria that quickly thrive in anoxic seawater </li></ul>
  8. 8. <ul><li>Open Oceans: Has low inorganic nutrient and organic carbon levels so life is relatively scarce </li></ul><ul><li>10 5 - 10 6 prokaryotes and 10 4 per ml eukaryotes </li></ul><ul><li>How do these organisms survive? </li></ul><ul><ul><li>Oxygenic and aerobic anoxygenic photosynthesis ( Prochlorococcus, Trichodesmium and Ostreococcus ) </li></ul></ul><ul><ul><li>Proteoredopsin: Converts light energy to ATP </li></ul></ul><ul><ul><ul><li>Previously only known in Halobacterium </li></ul></ul></ul><ul><ul><ul><li>A process that enables life in oligotrophic environments </li></ul></ul></ul>
  9. 9. Prochlorococcus Ostreococcus Trichodesmium
  10. 10. Archaea/Bacteria distribution: <ul><li>Phylogenetic stains </li></ul><ul><li>Bacteria dominate among phototrophs - photic zone (top 300 m) </li></ul><ul><li>Archaea ( Crenarcheota ) in deep oceans </li></ul><ul><li>In the world oceans: </li></ul><ul><li>1.3x10 28 Archaea and 3.1x10 28 Bacteria </li></ul>
  11. 11. Deep-sea Microbiology <ul><li>0 - 300 m; the photic zone </li></ul><ul><li>300 - 1000 m; chemotrophs and psychrophiles; 2 - 3 o C </li></ul><ul><li>< 1000 m low activities (cold, high pressure,scarce nutrients) microbes are: psychrophiles, barophiles, oligotrophs </li></ul><ul><li>How do we study the deep oceans? - submersibles </li></ul>
  12. 12. Barotolerant and barophilic bacteria: <ul><li>Barotolerant (3 km) vs. barophiles (4 - 6 km) vs. extreme and obligate barophiles (10 km) e.g., Moritella : cannot tolerate decompression and grows optimally at 2 o C </li></ul><ul><li>10 m = 1 atm </li></ul><ul><li>Mechanisms: </li></ul><ul><ul><li>Increased substrate binding capacity of enzymes </li></ul></ul><ul><ul><li>Increased unsaturation of fatty acids in membranes </li></ul></ul><ul><ul><li>Pressure controlled gene expression (e.g., OmpH) </li></ul></ul>
  13. 13. Hydrothermal Vents <ul><li>Sea floor spreading centers (rifts) </li></ul><ul><li>Warm vents (6-23 o C) </li></ul><ul><li>Hot vents (270 - 380 o C) - “black smokers” </li></ul><ul><li>Ecosystem is energized by chemical energy </li></ul><ul><li>Steep gradients </li></ul>
  14. 14. Deep-sea vent communities: <ul><li>How can life exist at 380 o C and at extremely high pressure? </li></ul><ul><li>Symbiosis of animals with chemoautotrophic bacteria H 2 S, H 2 , NH 4+ , Mn 2+ , CO </li></ul><ul><li>Animals: Giant tubeworms, clams and mussels </li></ul><ul><li>Microbes present here are sulfur oxidizers ( Thiobacillus , Begiatoa, Thiomicrospira, Thiothrix ) </li></ul>
  15. 15. Source:
  16. 16. Nutrition of vent animals: <ul><li>Animals fed on bacterial products and biomass </li></ul><ul><li>Endosymbiotic bacteria are located in trophosomes (3.7x10 9 cells per g) - pure cultures found these to be similar to Thiovulum </li></ul><ul><li>Animals produce hemoglobin-like proteins that transport H 2 S, O 2 , and CO 2 to the microbes </li></ul><ul><li>Evidence from sulfur stable isotope signatures (34S/32S) implicating H2S as the S source </li></ul><ul><li>Chemolithotrophic ectosymbionts of Alvinella (Pompeii worm) is also thought to provide nutrients to its host </li></ul>
  17. 17. <ul><ul><li>Alvinella pompejana </li></ul></ul>
  18. 18. Superheated water: black smokers <ul><li>Water at 450 o C rich in metal sulfides </li></ul><ul><li>“ Chimney” is formed when metal sulfide precipitate </li></ul><ul><li>Hydrothermal fluid is sterile (no life at > 150 o C) </li></ul><ul><li>Steep physical chemical gradient through the chimney’s wall </li></ul><ul><li>Where the most hyperthermophilic Archaea ( Methanopyrus , Pyrolobus and Pyrodictium ) live </li></ul>
  19. 19. References <ul><li>Madigan, M.T., Martinko, J.M. and Parker J. 2003. Brock Biology of Microorganisms , 10 th ed. Prentice Hall: New Jersey, USA. Pages 643-651 </li></ul><ul><li>Partensky, Hess and Vaulot. 1999. Prochlorococcus, a Marine Photosynthetic Prokaryote of Global Significance. Microbiology and Molecular Biology Reviews, vol. 63, no. 1, pages 106-127 </li></ul><ul><li>Environmental Protection Agency (EPA). 2006. Marine Ecosystems. Accessed on Nov 19, 2006 from http:// </li></ul><ul><li>Birgit, Reinert. 2002. Marine Microbes: Genomic tools reveal unexpected diversity of ocean life. Accessed on Nov 20, 2006 from </li></ul><ul><li>Touchette, Nancy. 2003. How the Other Half Lives: Marine Microbes Capture the Limelight. Accessed on Nov 20, 2006 from </li></ul>
  20. 20. Thank you for listening!