Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C4-C3 semi-arid vegetation transitions

A - Papers appearing in refereed journals

Puttock, A., Dungait, J. A. J., Bol, R., Dixon, E. R., Macleod, C. J. A. and Brazier, R. E. 2012. Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C4-C3 semi-arid vegetation transitions. Rapid Communications in Mass Spectrometry. 26 (20), pp. 2386-2392.

AuthorsPuttock, A., Dungait, J. A. J., Bol, R., Dixon, E. R., Macleod, C. J. A. and Brazier, R. E.
Abstract

RATIONALE Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C4 to C3 vegetation with characteristic d13C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. METHODS Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C4-C3 dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 2022 isotope ratio mass spectrometer to determine bulk d13C values. RESULTS Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p <0.05) in the bulk d13C values of C4 Bouteloua sp. (grama) grassland, C3 Larrea tridentata (creosote) shrubland and C3 Pinus edulis/Juniperus monosperma (pinon-juniper) woodland sites. Significantly, this distinctive d13C value was maintained in the bulk d13C values of fluvially eroded sediment from each of the sites, with no significant variation between surface sediment and eroded sediment values. CONCLUSIONS The significant differences in bulk d13C values between sites were dependent on vegetation input. Importantly, these values were robustly expressed in fluvially eroded sediments, suggesting that stable isotope analysis is suitable for tracing sediment fluxes. Due to the prevalent nature of these dryland vegetation transitions in the USA and globally, further development of stable isotope ratio mass spectrometry has provided a valuable tool for enhanced understanding of functional changes in these ecosystems. Copyright (c) 2012 John Wiley & Sons, Ltd.

KeywordsBiochemical Research Methods; Chemistry, Analytical; Spectroscopy
Year of Publication2012
JournalRapid Communications in Mass Spectrometry
Journal citation26 (20), pp. 2386-2392
Digital Object Identifier (DOI)doi:10.1002/rcm.6257
PubMed ID22976204
Open accessPublished as non-open access
FunderUniversity of Exeter
NSF
British Society for Geomorphology
Biotechnology and Biological Sciences Research Council
Rothamsted Research
Funder project or codeSEF
Processes and mechanisms of the interactions between grasslands and water
Soil and organic matter processes
Output statusPublished
Publication dates
Online10 Sep 2012
Publication process dates
Accepted23 Apr 2012
Copyright licensePublisher copyright
PublisherWiley
ISSN0951-4198

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