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

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

3. Fe Isotopes 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 Johnson and Beard, 2006. GSA Today, Vol. 16(11), pp. 4-10.

4. Biomineralization: Forming Biogenic Minerals BIM biologically induced mineralization (Fe bacteria, Sulfate reducers) BCM biologically controlled mineralization (Magnetotactic bacteria, Shewanella) Types of oxides: Magnetite (Fe 3 O 4 ), Greigite (Fe 3 S 4 ), Pyrrhotite (Fe 7 S 8 ) 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

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

6. Magnetospirillum gryphiswaldense 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 Magnetic Bacteria Characteristics  Bacteria only  Motile, Microaerophiles  Magnetosomes

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

8. http://www.mpi-bremen.de/magneto/research/

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

10. http://www.mpi-bremen.de/magneto/research/ Biochemistry of Magnetosome Formation 1.Fe +3 reduction and uptake by siderophores 2.Fe +2 uptake within magnetosome membrane 3.Oxidation of Fe +2 to Fe +3

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