Hydrogen and carbon isotope fractionation in modern plant wax n-alkanes from the Falkland Islands

Megan C. Corcoran; Aaron F. Diefendorf; Thomas V. Lowell; Brenda L. Hall; Meghan M. Spoth; Anna Schartman; Paul Brickle

doi:10.1016/j.orggeochem.2022.104404

Hydrogen and carbon isotope fractionation in modern plant wax n-alkanes from the Falkland Islands

Megan C. Corcoran, Aaron F. Diefendorf, Thomas V. Lowell, Brenda L. Hall, Meghan M. Spoth, Anna Schartman, Paul Brickle

Continental Scientific Drilling Facility

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

The hydrogen isotopic composition of terrestrial plant waxes (δ²H_wax) is widely used to reconstruct past hydroclimate. δ²H_wax values reflect plant source water or precipitation δ²H (δ²H_precip) values, and when extracted from sediment archives, records of past δ²H_precip values can be generated. In order to better interpret these δ²H_wax records, modern calibrations between plant waxes and source water are required when vegetation and location diverge from plant calibrations in other regions. To date, no modern study has examined how δ²H_wax values and source water δ²H values relate in the southern mid- and high-latitude maritime climatic regions where the climate is affected by the Southern Hemisphere Westerly Wind Belt. We present the first modern calibration of δ²H_wax values on the Falkland Islands by analyzing n-alkane plant wax concentrations, δ²H and δ¹³C values from 11 of the most common plant species, one lichen species, and surface lake sediment samples from four sites on Mount Usborne on East Falkland. Based on plant wax concentrations, the most commonly observed plants on the landscape, Empetrum rubrum and Cortaderia pilosa, are contributing the most to the waxes in sediment archives. We calculate the fractionation between the n-C₂₉ alkane δ²H_wax and δ²H_precip values (ε²H_wax/precip) for all plant species to be –110 ± 17‰ (1σ, n = 22), which is similar to the global average ε²H_wax/precip. Observed and modelled monthly δ²H_precip values indicate that δ²H_wax values can be interpreted as mean annual δ²H_precip values, ultimately establishing the framework for utilizing plant wax-based paleoreconstructions from the mid-latitude maritime climatic regions.

Original language	English (US)
Article number	104404
Journal	Organic Geochemistry
Volume	166
DOIs	https://doi.org/10.1016/j.orggeochem.2022.104404
State	Published - Apr 2022

Bibliographical note

Funding Information:
We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation ( EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research ( PRF #60163-ND2 to AFD).

Funding Information:
We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation (EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research (PRF #60163-ND2 to AFD).

Publisher Copyright:
© 2022 Elsevier Ltd

Keywords

Falkland Islands
Fractionation
Hydrogen isotopes
N-alkanes
Plant wax
Terrestrial biomarkers

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10.1016/j.orggeochem.2022.104404

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title = "Hydrogen and carbon isotope fractionation in modern plant wax n-alkanes from the Falkland Islands",

abstract = "The hydrogen isotopic composition of terrestrial plant waxes (δ2Hwax) is widely used to reconstruct past hydroclimate. δ2Hwax values reflect plant source water or precipitation δ2H (δ2Hprecip) values, and when extracted from sediment archives, records of past δ2Hprecip values can be generated. In order to better interpret these δ2Hwax records, modern calibrations between plant waxes and source water are required when vegetation and location diverge from plant calibrations in other regions. To date, no modern study has examined how δ2Hwax values and source water δ2H values relate in the southern mid- and high-latitude maritime climatic regions where the climate is affected by the Southern Hemisphere Westerly Wind Belt. We present the first modern calibration of δ2Hwax values on the Falkland Islands by analyzing n-alkane plant wax concentrations, δ2H and δ13C values from 11 of the most common plant species, one lichen species, and surface lake sediment samples from four sites on Mount Usborne on East Falkland. Based on plant wax concentrations, the most commonly observed plants on the landscape, Empetrum rubrum and Cortaderia pilosa, are contributing the most to the waxes in sediment archives. We calculate the fractionation between the n-C29 alkane δ2Hwax and δ2Hprecip values (ε2Hwax/precip) for all plant species to be –110 ± 17‰ (1σ, n = 22), which is similar to the global average ε2Hwax/precip. Observed and modelled monthly δ2Hprecip values indicate that δ2Hwax values can be interpreted as mean annual δ2Hprecip values, ultimately establishing the framework for utilizing plant wax-based paleoreconstructions from the mid-latitude maritime climatic regions.",

keywords = "Falkland Islands, Fractionation, Hydrogen isotopes, N-alkanes, Plant wax, Terrestrial biomarkers",

author = "Corcoran, {Megan C.} and Diefendorf, {Aaron F.} and Lowell, {Thomas V.} and Hall, {Brenda L.} and Spoth, {Meghan M.} and Anna Schartman and Paul Brickle",

note = "Funding Information: We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation ( EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research ( PRF #60163-ND2 to AFD). Funding Information: We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation (EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research (PRF #60163-ND2 to AFD). Publisher Copyright: {\textcopyright} 2022 Elsevier Ltd",

year = "2022",

month = apr,

doi = "10.1016/j.orggeochem.2022.104404",

language = "English (US)",

volume = "166",

journal = "Organic Geochemistry",

issn = "0146-6380",

publisher = "Elsevier Ltd",

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T1 - Hydrogen and carbon isotope fractionation in modern plant wax n-alkanes from the Falkland Islands

AU - Corcoran, Megan C.

AU - Diefendorf, Aaron F.

AU - Lowell, Thomas V.

AU - Hall, Brenda L.

AU - Spoth, Meghan M.

AU - Schartman, Anna

AU - Brickle, Paul

N1 - Funding Information: We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation ( EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research ( PRF #60163-ND2 to AFD). Funding Information: We would like to thank Sarah Hammer for laboratory support and MacKenzie King and Samuel Little for their assistance with sample preparation. We also thank Antony Smith of Discovery Falklands who provided key logistical support, and the staff at the South Atlantic Environmental Research Institute and the Falklands Islands Government for assistance. We also wish to thank Gill Smith and the late Colin Smith, landowners, Ken Morrison, Teresa Smith, Richard Fogerty, and the many others in the Falkland Islands who assisted us. We would like the thank the editors, Nemiah Ladd, and two anonymous reviewers for comments that improved this manuscript. This research was supported by the US National Science Foundation (EAR-1636740 and EAR-2039795 to AFD and TVL). Sample collection was funded by the University of Maine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of the research (PRF #60163-ND2 to AFD). Publisher Copyright: © 2022 Elsevier Ltd

PY - 2022/4

Y1 - 2022/4

N2 - The hydrogen isotopic composition of terrestrial plant waxes (δ2Hwax) is widely used to reconstruct past hydroclimate. δ2Hwax values reflect plant source water or precipitation δ2H (δ2Hprecip) values, and when extracted from sediment archives, records of past δ2Hprecip values can be generated. In order to better interpret these δ2Hwax records, modern calibrations between plant waxes and source water are required when vegetation and location diverge from plant calibrations in other regions. To date, no modern study has examined how δ2Hwax values and source water δ2H values relate in the southern mid- and high-latitude maritime climatic regions where the climate is affected by the Southern Hemisphere Westerly Wind Belt. We present the first modern calibration of δ2Hwax values on the Falkland Islands by analyzing n-alkane plant wax concentrations, δ2H and δ13C values from 11 of the most common plant species, one lichen species, and surface lake sediment samples from four sites on Mount Usborne on East Falkland. Based on plant wax concentrations, the most commonly observed plants on the landscape, Empetrum rubrum and Cortaderia pilosa, are contributing the most to the waxes in sediment archives. We calculate the fractionation between the n-C29 alkane δ2Hwax and δ2Hprecip values (ε2Hwax/precip) for all plant species to be –110 ± 17‰ (1σ, n = 22), which is similar to the global average ε2Hwax/precip. Observed and modelled monthly δ2Hprecip values indicate that δ2Hwax values can be interpreted as mean annual δ2Hprecip values, ultimately establishing the framework for utilizing plant wax-based paleoreconstructions from the mid-latitude maritime climatic regions.

AB - The hydrogen isotopic composition of terrestrial plant waxes (δ2Hwax) is widely used to reconstruct past hydroclimate. δ2Hwax values reflect plant source water or precipitation δ2H (δ2Hprecip) values, and when extracted from sediment archives, records of past δ2Hprecip values can be generated. In order to better interpret these δ2Hwax records, modern calibrations between plant waxes and source water are required when vegetation and location diverge from plant calibrations in other regions. To date, no modern study has examined how δ2Hwax values and source water δ2H values relate in the southern mid- and high-latitude maritime climatic regions where the climate is affected by the Southern Hemisphere Westerly Wind Belt. We present the first modern calibration of δ2Hwax values on the Falkland Islands by analyzing n-alkane plant wax concentrations, δ2H and δ13C values from 11 of the most common plant species, one lichen species, and surface lake sediment samples from four sites on Mount Usborne on East Falkland. Based on plant wax concentrations, the most commonly observed plants on the landscape, Empetrum rubrum and Cortaderia pilosa, are contributing the most to the waxes in sediment archives. We calculate the fractionation between the n-C29 alkane δ2Hwax and δ2Hprecip values (ε2Hwax/precip) for all plant species to be –110 ± 17‰ (1σ, n = 22), which is similar to the global average ε2Hwax/precip. Observed and modelled monthly δ2Hprecip values indicate that δ2Hwax values can be interpreted as mean annual δ2Hprecip values, ultimately establishing the framework for utilizing plant wax-based paleoreconstructions from the mid-latitude maritime climatic regions.

KW - Falkland Islands

KW - Fractionation

KW - Hydrogen isotopes

KW - N-alkanes

KW - Plant wax

KW - Terrestrial biomarkers

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U2 - 10.1016/j.orggeochem.2022.104404

DO - 10.1016/j.orggeochem.2022.104404

M3 - Article

AN - SCOPUS:85127464611

SN - 0146-6380

VL - 166

JO - Organic Geochemistry

JF - Organic Geochemistry

M1 - 104404

ER -

Hydrogen and carbon isotope fractionation in modern plant wax n-alkanes from the Falkland Islands

Abstract

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Keywords

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