Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Kateryna Klochko
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_204-2


Borate is a common oxoanion (BO33−) found in borate minerals (e.g., boracite, borax, kernite, colemanite, etc.), some borosilicates (e.g., tourmaline), and in association with natural carbonates. In natural aqueous environments, borates exist in equilibrium with boric acid B(OH)3° and borate anion B(OH)4 . The pH-dependent equilibrium between these species in seawater (pKa = 8.597, (Dickson 1990)) is accompanied by boron isotope fractionation of 27.2‰ (Klochko et al. 2006). The two naturally occurring and stable isotopes are 11B (80.1 %) and 10B (19.9 %). The mass difference results in a wide range of boron isotopic compositions in terrestrial environments, and boron isotopic compositions in marine carbonates have been used as a paleo-pH proxy of the oceans (Hemming and Hanson 1992). Borates have also been found to stabilize ribose (Ricardo et al. 2004), which may have been important for the origin of life on early Earth, although the prebiotic availability of borate...


Isotopic Composition Stable Isotope Aqueous Environment Bioorganic Chemistry Boric Acid 
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References and Further Reading

  1. Dickson AG (1990) Thermodynamics of the dissociation of boric acid in synthetic seawater from 273.15 to 318.15 K. Deep-Sea Res 37:755–766ADSCrossRefGoogle Scholar
  2. Hazen RH, Papineau D, Bleeker W, Downs RT, Ferry JM, McCoy TJ, Sverjensky DA, Yang H (2008) Mineral evolution. Am Mineral 93:1693–1720CrossRefGoogle Scholar
  3. Hemming NG, Hanson GN (1992) Boron isotopic composition and concentration in modern marine carbonates. Geochim Cosmochim Ac 56:537–543ADSCrossRefGoogle Scholar
  4. Klochko K, Kaufman AJ, Yao W, Byrne RH, Tossell JA (2006) Experimental measurement of boron isotope fractionation in seawater. Earth Planet Sci Lett 248:261–270CrossRefGoogle Scholar
  5. Ricardo A, Carrigan MA, Olcott AN, Benner SA (2004) Borate minerals stabilize ribose. Science 303:196CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Carnegie Institution of WashingtonWashingtonUSA