Leaf Wax δD and δ13C in Soils Record Hydrological and Environmental Information Across a Climatic Gradient in Israel

Yonaton Goldsmith*, Pratigya J. Polissar, Peter B. deMenocal, Wallace S. Broecker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The hydrogen (δDwax) and carbon (δ13Cwax) isotope compositions of long-chain alkanes derived from plant waxes record hydrological and environmental conditions. However, the integration of plant n-alkanes into the sedimentary cycle, the variability of δDwax and δ13Cwax in soils, and the paleoclimate applicability in paleosols and archaeological sediments are poorly constrained. We sampled plants and soils across a steep climate transect in Israel to understand how plant type and environmental parameters shape δ13Cwax and δDwax. This transect has three advantages: existence of long-term precipitation isotopic composition (δDr) records, a single wet season potentially reduces variability due to seasonality, and abandoned Byzantine period (~300–600 AD) agricultural terraces that reduce modern and ancient soil mixing and provide age constraints. We find that soil δ13Cwax is constant (0.4‰, 1σ) across a 500- to 1,300-mm/year rainfall gradient and appears insensitive to rainfall amount, unlike bulk plant δ13C. The absence of a rainfall effect suggests that δ13Cwax may be better suited to reconstructing C3/C4 plant ratios than bulk δ13C. Homologue average soil δDwax significantly correlate with δDr, and the offset between δDr and soil δDwaxapp) correlates with growing season relative humidity. The seasonality of leaf production accounted for at most ~10% of total plant δDwax variability. Lastly, soil δDwax and δ13Cwax variability is reduced by ~80% relative to plant δDwax and δ13Cwax variability. Our results show that soil δDwax and δ13Cwax faithfully record δDr and landscape C3-C4 plant contributions and thus support the utility of these proxy data in paleosols and archaeological sites.

Original languageAmerican English
Pages (from-to)2898-2916
Number of pages19
JournalJournal of Geophysical Research: Biogeosciences
Volume124
Issue number9
DOIs
StatePublished - 1 Sep 2019

Bibliographical note

Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.

Keywords

  • leaf wax carbon isotope
  • leaf wax hydrogen isotope
  • long-chain alkane
  • plant
  • soil

Fingerprint

Dive into the research topics of 'Leaf Wax δD and δ13C in Soils Record Hydrological and Environmental Information Across a Climatic Gradient in Israel'. Together they form a unique fingerprint.

Cite this