Plant wax D/H fractionation in modern plants from the Falkland Islands

Abstract

The hydrogen isotopic composition (δ²H) of plant waxes is a powerful tool for reconstructing past precipitation, yet its accuracy relies on constraining the apparent fractionation (ε) between plants and source water (ε_wax/water). While regional information on n -alkanes exists in the Falkland Islands, values for n -alkanoic acids remain unconstrained, despite the latter often being more abundant in sedimentary archives. To address this, we analysed paired n -alkanes and n -alkanoic acids from modern plant species in the Falkland Islands. We present a regional dataset for n-alkanoic acids (n = 9), finding a mean fractionation (ε_acid/precip) of –147 ± 22‰. This is broadly consistent with co-occurring n -alkanes (–137 ± 20‰), validating the use of n -alkanoic acids as a complementary proxy. Comparing our n -alkane data with previous studies reveals a ∼ 28‰ offset in (ε_{alkane/precip}), which we attribute to distinct plant communities and year-to-year variability in precipitation δ²H affecting source water. We also assess the influence of high-biomass species on landscape-scale (ε_{alkane/precip}). Our new abundance-weighted mean fractionation factor for the combined n -alkane dataset (–129‰) is statistically indistinguishable from the unweighted community mean (–121‰) and demonstrates that high-biomass species do not skew the landscape-scale signal, providing confidence in using δ²H for quantitative paleoclimate reconstruction in the Falkland Islands.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata

Altmetrics