Molecular Paleohydrology: Interpreting the Hydrogen-Isotopic Composition of Lipid Biomarkers from Photosynthesizing Organisms
Tóm tắt
Hydrogen-isotopic abundances of lipid biomarkers are emerging as important proxies in the study of ancient environments and ecosystems. A decade ago, pioneering studies made use of new analytical methods and demonstrated that the hydrogen-isotopic composition of individual lipids from aquatic and terrestrial organisms can be related to the composition of their growth (i.e., environmental) water. Subsequently, compound-specific deuterium/hydrogen (D/H) ratios of sedimentary biomarkers have been increasingly used as paleohydrological proxies over a range of geological timescales. Isotopic fractionation observed between hydrogen in environmental water and hydrogen in lipids, however, is sensitive to biochemical, physiological, and environmental influences on the composition of hydrogen available for biosynthesis in cells. Here we review the factors and processes that are known to influence the hydrogen-isotopic compositions of lipids—especially n-alkanes—from photosynthesizing organisms, and we provide a framework for interpreting their D/H ratios from ancient sediments and identify future research opportunities.
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Tài liệu tham khảo
Benthien A, van der Meer MTJ, Schouten S, Zondervan I, Bijma J. 2009. The effect of growth rate and light intensity on the hydrogen isotopic composition of long-chain alkenones produced by Emiliania huxleyi. Presented at EGU Gen. Assem. 2009, Apr. 19–24, Vienna
Bowen GJ. 2009. The Online Isotopes in Precipitation Calculator(OIPC),version 2.2. http://www.waterisotopes.org
Craig H, 1965, Stable Isotopes in Oceanographic Studies and Paleotemperatures, 9
Luo YH, 1991, Plant Cell Physiol., 32, 897
Sachse D, 2004, Int. J. Earth Sci., 93, 554