Comparison of δ2H values of leaf wax n-alkanes and n-alkanoic acids in subtropical angiosperms

Abstract. Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf wax derived long chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. Our deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes, but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow to distinguish between different vegetation types, but caution must be exercised given the large species-specific variability of chain length patterns. An updated endmember model with a new n-alkane ratio is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

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Leaf waxes in litter and topsoils along a European transect

SOIL ◽

10.5194/soil-2-551-2016 ◽

2016 ◽

Vol 2 (4) ◽

pp. 551-564 ◽

Cited By ~ 30

Author(s):

Imke K. Schäfer ◽

Verena Lanny ◽

Jörg Franke ◽

Timothy I. Eglinton ◽

Michael Zech ◽

...

Keyword(s):

Chain Length ◽

Deciduous Forest ◽

Soil Depth ◽

Large Species ◽

Alkanoic Acid ◽

Climate Conditions ◽

Leaf Wax ◽

Leaf Waxes ◽

Forest Sites ◽

Alkanoic Acids

Abstract. Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C31 + n-C33) / (n-C27 + n-C31 + n-C33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

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Distinguishing between old and modern permafrost sources with compound-specific δ<sup>2</sup>H analysis

10.5194/tc-2017-17 ◽

2017 ◽

Author(s):

Jorien E. Vonk ◽

Tommaso Tesi ◽

Lisa Bröder ◽

Henry Holmstrand ◽

Gustaf Hugelius ◽

...

Keyword(s):

Isotope Composition ◽

Quantitative Measure ◽

The Arctic ◽

Near Surface ◽

Leaf Wax ◽

Leaf Waxes ◽

Shelf Slope ◽

Alkanoic Acids ◽

Long Chain ◽

Ice Complex

Abstract. Pleistocene ice complex permafrost deposits contain roughly a quarter of the organic carbon (OC) stored in permafrost terrain. When permafrost thaws, its OC is remobilized into the (aquatic) environment where it is available for degradation, transport or burial. Aquatic or coastal environments contain sedimentary reservoirs that can serve as archives of past climatic change. As permafrost thaw is increasing throughout the Arctic, these reservoirs are important locations to assess the fate of remobilized permafrost OC. We here present compound-specific deuterium (δ2H) analysis on leaf waxes as a tool to distinguish between OC released from thawing Pleistocene permafrost (Ice Complex Deposits; ICD) and from thawing Holocene permafrost (from near-surface soils). Bulk geochemistry (%OC, δ13C, %total nitrogen; TN) was analyzed as well as the concentrations and δ2H signatures of long-chain n-alkanes (C21 to C33) and mid/long-chain n-alkanoic acids (C16 to C30) extracted from both ICD-PF samples (n = 9) and modern vegetation/O-horizon (Topsoil-PF) samples (n = 9) from across the northeast Siberian Arctic. Results show that these Topsoil-PF samples have higher %OC, higher OC/TN values, and more depleted δ13C-OC values than ICD-PF samples, suggesting that these former samples trace a fresher soil and/or vegetation source. Median concentrations of high-molecular weight n-alkanes (sum of C25-C27-C29-C31) were 210 ± 350 µg/gOC (median ± IQR) for Topsoil-PF and 250 ± 81 µg/gOC for ICD-PF samples. Long-chain n-alkanoic acids (sum of C22-C24-C26-C28) were more abundant than long-chain n-alkanes, both in Topsoil-PF samples (4700 ± 3400 µg/gOC) and in ICD samples (6630 ± 3500 µg/gOC). Whereas the two investigated sources differ on the bulk geochemical level, they are, however, virtually indistinguishable when using leaf wax concentrations and ratios. However, on the molecular-isotope level, leaf wax biomarker δ2H values are statistically different between Topsoil-PF and ICD-PF. The mean δ2H value of C29 n-alkane was −246 ± 13 ‰ (mean ± stdev) for Topsoil-PF and −280 ± 12 ‰ for ICD-PF, whereas the C31 n-alkane was −247 ± 23 ‰ for Topsoil-PF and −297 ± 15 ‰ for ICD-PF. The C28 n-alkanoic acid δ2H value was −220 ± 15 ‰ for Topsoil-PF and −267 ± 16 ‰ for ICD-PF. With a dynamic isotopic range (difference between two sources) of 34 to 50 ‰, the isotopic fingerprints of individual, abundant, biomarker molecules from leaf waxes can thus serve as end-members to distinguish between these two sources. We tested this molecular δ2H tracer along with another source-distinguishing approach, dual-carbon (δ13C-δ14C) isotope composition of bulk OC, for a surface sediment transect in the Laptev Sea. Results show that general offshore patterns along the shelf-slope transect are similar, but the source apportionment between the approaches vary, which may highlight the advantages of either. The δ2H molecular approach has the advantage that it circumvents uncertainties related to a marine end-member, yet the δ13C-δ14C approach has the advantage that it represents the bulk OC fraction thereby avoiding issues related to the molecular-bulk upscaling challenge. This study indicates that the application of δ2H leaf wax values has potential to serve as a complementary quantitative measure of the source and differential fate of OC thawed out from different permafrost compartments.

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Effect of Rainfall Exposure on Leaf Wettability in Near-Isogenic Barley Lines with Different Leaf Wax Content.

Journal of Agricultural Meteorology ◽

10.2480/agrmet.54.155 ◽

1998 ◽

Vol 54 (2) ◽

pp. 155-160 ◽

Cited By ~ 6

Author(s):

Shigemi TANAKAMARU ◽

Toshihiko TAKEHANA ◽

Kazuyoshi KIMURA

Keyword(s):

Leaf Wax ◽

Wax Content ◽

Leaf Wettability

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Reactions of 2-(perfluoroalkyl)ethane thiols with 1,6-heptadiene and 4-substituted 1,6-heptadienes: the synthesis of RFethanethio-cyclopentanoic and -dioic acids; and, “geminal-twin-tail” bis-(perfluoroalkylethanethio)alkanoic acids

Journal of Fluorine Chemistry ◽

10.1016/j.jfluchem.2004.03.012 ◽

2005 ◽

Vol 126 (1) ◽

pp. 7-15 ◽

Cited By ~ 11

Author(s):

Neal O. Brace

Keyword(s):

Alkanoic Acids

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Molecular association of normal alkanoic acids with their thallium(I) salts: a new homologous series of fatty acid metal soaps

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)37448-4 ◽

1997 ◽

Vol 38 (2) ◽

pp. 361-372

Author(s):

M Fernández-García ◽

M V García ◽

M I Redondo ◽

J A Cheda ◽

M Fernández-García ◽

...

Keyword(s):

Fatty Acid ◽

Homologous Series ◽

Molecular Association ◽

Alkanoic Acids ◽

Metal Soaps

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A long-term investigation of the variation in leaf wax n-alkanes responding to climate on Dongling Mountain, north China

Quaternary International ◽

10.1016/j.quaint.2021.04.020 ◽

2021 ◽

Author(s):

Minrui Shi ◽

Jiamao Han ◽

Guoan Wang ◽

Jia Wang ◽

Yaowen Han ◽

...

Keyword(s):

North China ◽

Leaf Wax

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Honey-collecting in prehistoric West Africa from 3500 years ago

Nature Communications ◽

10.1038/s41467-021-22425-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Julie Dunne ◽

Alexa Höhn ◽

Gabriele Franke ◽

Katharina Neumann ◽

Peter Breunig ◽

...

Keyword(s):

West Africa ◽

Residue Analysis ◽

Fatty Acyl ◽

Prehistoric Pottery ◽

Alkanoic Acids ◽

Complex Lipid ◽

Ceramic Vessels ◽

Early Farming ◽

Early Farmers ◽

Chemical Evidence

AbstractHoney and other bee products were likely a sought-after foodstuff for much of human history, with direct chemical evidence for beeswax identified in prehistoric ceramic vessels from Europe, the Near East and Mediterranean North Africa, from the 7th millennium BC. Historical and ethnographic literature from across Africa suggests bee products, honey and larvae, had considerable importance both as a food source and in the making of honey-based drinks. Here, to investigate this, we carry out lipid residue analysis of 458 prehistoric pottery vessels from the Nok culture, Nigeria, West Africa, an area where early farmers and foragers co-existed. We report complex lipid distributions, comprising n-alkanes, n-alkanoic acids and fatty acyl wax esters, which provide direct chemical evidence of bee product exploitation and processing, likely including honey-collecting, in over one third of lipid-yielding Nok ceramic vessels. These findings highlight the probable importance of honey collecting in an early farming context, around 3500 years ago, in West Africa.

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