Leaf water deuterium enrichment shapes leaf wax n-alkane delta D values of angiosperm plants II: Observational evidence and global implications Academic Article uri icon

abstract

  • Leaf wax n-alkanes are long-chain hydrocarbons that can persist in sedimentary records over geological timescales. Since their hydrogen isotopic composition (expressed as a D value) can be correlated to the D values of precipitation, leaf wax n-alkane D values have been advocated as new and powerful proxies for paleohydrological research. The exact type of hydrological information that is recorded in the D values of leaf wax n-alkanes remains, however, unclear. In a companion paper we provide experimental evidence showing that the D values of leaf wax n-alkanes of angiosperm plants grown under controlled environmental conditions not only reflect D values of precipitation - as has often been assumed - but that evaporative deuterium (D)-enrichment of leaf water has an additional critical effect on their D values. Here we present a detailed observational study that illustrates that evaporative D-enrichment of leaf water also affects the D values of leaf wax n-alkanes in plants from natural ecosystems along a 1500. km climate gradient in Northern Australia. Based on global simulations of leaf water D-enrichment we show that the effects of evaporative D-enrichment of leaf water on leaf wax n-alkane D values is relevant in all biomes but that it is particularly important in arid environments. Given the combined influence of precipitation D values and leaf water D-enrichment we argue that leaf wax n-alkane D values contain an integrated signal that can provide general hydrological information, e.g. on the aridity of a catchment area. We also suggest that more specific hydrological information and even plant physiological information can be obtained from leaf wax n-alkanes if additional indicators are available to constrain the plant- and precipitation-derived influences on their D values. As such, our findings have important implications for the interpretation of leaf wax n-alkane D values from paleohydrological records. In addition, our investigations open the door to employ D values of leaf wax n-alkanes as new ecohydrological proxies in contemporary plant and ecosystem sciences. 2012 Elsevier Ltd.

published proceedings

  • GEOCHIMICA ET COSMOCHIMICA ACTA

altmetric score

  • 3.35

author list (cited authors)

  • Kahmen, A., Hoffmann, B., Schefuss, E., Arndt, S. K., Cernusak, L. A., West, J. B., & Sachse, D.

citation count

  • 172

complete list of authors

  • Kahmen, Ansgar||Hoffmann, Bernd||Schefuss, Enno||Arndt, Stefan K||Cernusak, Lucas A||West, Jason B||Sachse, Dirk

publication date

  • January 2013