Iron isotope biosignatures

Science

Volumn 285, Issue 5435, 1999, Pages 1889-1891

  Beard, Brian L ^a   Johnson, Clark M ^a   Cox, Lea ^b   Sun, Henry ^b   Nealson, Kenneth H ^b   Aguilar, Carmen ^c  

^a UNIVERSITY OF WISCONSIN MADISON   (United States)

^b CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

^c UNIVERSITY OF WISCONSIN MILWAUKEE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

IRON; ISOTOPE;

BACTERIUM; EARLY EARTH; MICROORGANISM;

ARTICLE; ASTRONOMY; CHEMICAL COMPOSITION; CONCENTRATION (PARAMETERS); FRACTIONATION; MOON; PALEOANTHROPOLOGY; PRECIPITATION; PRIORITY JOURNAL; ROCK; SEDIMENT; SHEWANELLA;

NASA CENTER JPL; NASA DISCIPLINE EXOBIOLOGY;

EARTH (PLANET); GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS; IRON; IRON ISOTOPES; MASS SPECTROMETRY; MOON;

ALGAE; BACTERIA (MICROORGANISMS); BRYOPHYTES; FUNGI; SHEWANELLA; SHEWANELLA ALGAE;

EID: 0033578925     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.285.5435.1889     Document Type: Article

References (18)

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10. 54Fe was added to an aliquot of each analyzed sample to normalize the measured iron isotope ratios for instrumental mass bias.
11. 7 cells/ml.
12. 7 cells/ml.
13. 7 cells/ml.
14. 6 cells/ml.
15. Fe(II) contents were determined with the ferrozine technique [L. C. Stookey, Anal. Chem. 42, 779 (1970)]. Ferrozine (1 g/liter) in Hepes buffer (50 mM) at pH 7 was used. A 0.1-ml sample, filtered through a 02-μm syringe filter, was mixed with 5 ml of the ferrozine solution. After about 5 min, the absorbance was measured at 562 nm on a spectrophotometer, which had been calibrated with Fe(II) solutions.
16. T. D. Bullen and P. M. McMahon, Eos 78, S173 (1997).
17. K. H. Nealson and C. R. Myers, Am. J. Sci. 290A, 35 (1990).
18. This work was supported by NASA grant NAGS-6342, NSF grant OPP-9713968, and the NASA Astrobiology Institute. We thank P. Brown, and C. Bowser for donating samples for Fe isotope analysis.