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March 10, 2009

March 10, 2009. Exam I due Thursday, March 12 (11am) Proposal descriptions due Thursday, March 26. Australian wrestles kangaroo from family home.

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March 10, 2009

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  1. March 10, 2009 • Exam I due Thursday, March 12 (11am) • Proposal descriptions due Thursday, March 26 Australian wrestles kangaroo from family home CANBERRA, Australia - When a dark intruder smashed through his bedroom window and repeatedly bounced on his bed, Beat Ettlin was initially relieved to discover it was a kangaroo.The kangaroo, which Ettlin said was around his height, 5 foot 9 inches (176 centimetres), left a trail of blood through the house and claw gouges in the wooden frame of his bed.Ettlin, who was left wearing just his shredded underpants and with scratch marks on his leg and buttocks, described himself as "lucky." Kangaroos rarely harm humans, but when they do, it is usually because they feel cornered. They have been known to disembowel people with the claws of their powerful hind legs.

  2. Fe Isotope Fractionation From: Beard et al., 1999, Science 285:1889-1892

  3. Modern Fe cycle No distinction for FeOB Distinct for DIRB Distinct for FeS (SRB) Early Earth Fe cycle Some kind of oxidant present Fe respiration 2.7-2.9 Ga Fe Isotopes Johnson and Beard, 2006. GSA Today, Vol. 16(11), pp. 4-10.

  4. BIM biologically induced mineralization (Fe bacteria, Sulfate reducers) BCM biologically controlled mineralization (Magnetotactic bacteria, Shewanella) Biomineralization:Forming Biogenic Minerals • Result of metabolic activity • Extracellular particles • Poorly crystallized minerals • Broad size distribution • Direct synthesis of mineral • Typically within cell • Well-ordered crystals • Narrow size distributions Types of oxides: Magnetite (Fe3O4), Greigite (Fe3S4), Pyrrhotite (Fe7S8)

  5. BCM: Shewanella • Ferrihydrite inclusions Glasauer, et al. 2002. Science Vol. 295:117.

  6. Magnetospirillum gryphiswaldense Magnetic Bacteria • Characteristics • Bacteria only • Motile, Microaerophiles • Magnetosomes http://www.mpi-bremen.de/magneto/research/ http://www.energy.soton.ac.uk/research/bio_magneto_bac.html http://geography.lancs.ac.uk/cemp/atlas/biogen/biogenic_1.htm

  7. http://www.calpoly.edu/~rfrankel/

  8. http://www.calpoly.edu/~rfrankel/ http://www.mpi-bremen.de/magneto/research/

  9. Function of Magnetic Particles? Magnetotaxis allows passive orientation Aerotaxis drives localization http://www.calpoly.edu/~rfrankel/ MOVIE link: http://www.biophysics.uwa.edu.au/STAWA/magbac_5.html

  10. Biochemistry of Magnetosome Formation Fe+3 reduction and uptake by siderophores Fe+2 uptake within magnetosome membrane Oxidation of Fe+2 to Fe+3 http://www.mpi-bremen.de/magneto/research/

  11. FOSSILIZED MAGNETOTACTIC BACTERIUM IN THE ORGUEIL METEORITE Tan and Van Landingham (1966) Image of freshly fractured surface of a chip from ALH84001 meteorite Image - NASA AMES Magnetic Minerals as Biomarkers • Consistent size indicates biogenic magnetite • Need better techniques to distinguish particles http://www.astrobio.net/news/print.php?sid=250 http://www.abc.net.au/science/news/space/SpaceRepublish_252236.htm

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