Variation in Hydrogen Isotope Composition Among Salt Marsh Plant Organic Compounds Highlights Biochemical Mechanisms Controlling Biosynthetic Fractionation

Eley, Yvette; White, Joseph D.; Dawson, Lorna; Hren, Michael T.; Pedentchouk, Nikolai

doi:10.1029/2018jg004403

Cited by 9 publications

(6 citation statements)

References 85 publications

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“…In this context, several studies provided insight on the controls on n-alkane distribution and δ 2 H wax of various plant communities in different environments and climates (Diefendorf and Freimuth, 2017;Liu and An, 2018 and refs therein). While a number of plant wax studies have investigated wetland vegetation such as at the Gannan Gahai lake or the Dajiuhu peatland in China (trees, grasses and aquatics; Duan et al, 2014;Zhao et al, 2018;Huang and Meyers, 2019), British coastal salt marshes (mainly halophytes; Eley et al, 2014Eley et al, , 2018 or high latitude bogs (Ficken et al, 1998;Pancost et al, 2002;Nichols et al, 2006Nichols et al, , 2010Brader et al, 2010), none to date focus specifically on the helophytic plant communities so common worldwide in temperate fens, marshes, and peri-lacustrine environments (e.g., Silliman and Schelske, 2003;Mead et al, 2005), from which derive a great number of continental paleo-archives (e.g., Fischer and Wilkes, 2003;Kaufman et al, 2020).…”

Section: Objectivesmentioning

confidence: 99%

“…Internal factors, linked to plant physiology (e.g., biosynthetic pathway, rooting depth) can also contribute to the variation in δ 2 H wax (Smith and Freeman, 2006;Gao et al, 2015;Cormier et al, 2018Cormier et al, , 2019Eley et al, 2018) and modulate the correlation between δ 2 H p and δ 2 H wax , normally expressed as the net (or apparent) 2 H-fractionation between n-alkanes and mean annual precipitation (e.g., ε 29/MAP ) (Liu et al, 2006(Liu et al, , 2016Hou et al, 2007b;Sachse et al, 2012;Gao et al, 2014a;Gamarra et al, 2016;Eley et al, 2018). Despite the resulting high inter-and intra-specific variability characterising δ 2 H wax (e.g., 40‰ between leaves of the same plant; Sachse et al, 2009;Newberry et al, 2015), larger datasets reveal a generally stable correlation between δ 2 H wax and δ 2 H p in plant communities and derived sediments (Chikaraishi and Naraoka, 2003;Sachse et al, 2006;Hou et al, 2008;Rao et al, 2009;Feakins and Sessions, 2010;Chen et al, 2022).…”

Section: Stable Isotopic Compositionmentioning

confidence: 99%

“…The cause of this behaviour is currently unknown. Drawing from prior investigations (Zhou et al, 2010;Eley et al, 2018), we posit that either environmental factors (e.g., aridity) or physiological influences may have affected the a) 2 H-composition of pyruvate, the precursor to both odd and even n-alkane homologues, and/or b) the availability of pyruvate from different sources (e.g., NADPH, carbohydrates; Schmidt et al, 2003;Ladd and Sachs, 2012). The production of n-alkanes is predominantly driven by oddnumbered homologues through the pyruvate-acetate pathway, and primarily utilises strongly 2 H-depleted NADPH derived pyruvate (Schmidt et al, 2003).…”

Section: Net 2 H-fractionationmentioning

confidence: 99%

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Leaf wax n-alkane distribution and hydrogen isotopic fractionation in fen plant communities of two Mediterranean wetlands (Tenaghi Philippon, Nisí fen—Greece)

Ardenghi,

Mulch,

McFarlin

et al. 2024

Front. Earth Sci.

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Many continental paleoclimate archives originate from wetland sedimentary sequences. While several studies have investigated biomarkers derived from peat-generating vegetation typical of temperate/boreal bogs (e.g., Sphagnum), only scant information is available on emergent plants predominant in temperate/subtropical coastal marshlands, peri-lacustrine and fen environments. Here, we address this gap, focusing on two wetlands in the Mediterranean (Nisí fen and Tenaghi Philippon, Greece). We examined the concentration, homologue distribution, and hydrogen stable isotopic composition (δ2H) of leaf wax n-alkanes in 13 fen plant species, their surrounding soil, and surface water during the wet growing season (spring) and the declining water table period (summer). Our findings indicate that local graminoid species primarily contribute to the soil n-alkane signal, with a lesser influence from forbs, likely owing to differences in morphology and vegetation structure. The δ2H values of surface and soil water align with local average annual precipitation δ2H, reflecting winter-spring precipitation. Consistently, the average δ2H of local surface, soil, and lower stem water showed negligible evaporative enrichment, confirming minimal 2H-fractionation during water uptake. We find that δ2H values of source water for wax compound synthesis in local fen plants accurately mirror local annual precipitation. Furthermore, despite differences between leaves and lower stems in n-alkane production rates, their δ2H values exhibit remarkable similarity, indicating a shared metabolic substrate, likely originating in leaves. Our net 2H-fractionation values (i.e., precipitation to leaf n-alkanes) align with those in Chinese highlands and other similar environments, suggesting consistency across diverse climatic zones. Notably, our data reveal a seasonal decrease in the carbon preference index (CPI) in plant samples, indicating wax lipid synthesis changes associated with increased aridity. Additionally, we introduce a new parity isotopic difference index (PID) based on the consistent δ2H difference between odd and even n-alkane homologues. The PID demonstrates a strong anticorrelation with plant CPI, suggesting a potential avenue to trace long-term aridity shifts through δ2H analysis of odd and even n-alkane homologues in sedimentary archives. While further development of the PID is necessary for broad application, these findings highlight the intricate interplay between plant physiology, environmental parameters, and sedimentary n-alkanes in unravelling past climatic conditions.

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Section: Objectivesmentioning

confidence: 99%

Section: Stable Isotopic Compositionmentioning

confidence: 99%

Section: Net 2 H-fractionationmentioning

confidence: 99%

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Leaf wax n-alkane distribution and hydrogen isotopic fractionation in fen plant communities of two Mediterranean wetlands (Tenaghi Philippon, Nisí fen—Greece)

Ardenghi,

Mulch,

McFarlin

et al. 2024

Front. Earth Sci.

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“…Bulk 13 C/ 12 C isotopic content in samples was determined as previously performed (Eley et al, 2018). Briefly, the mean δ 13 C values were measured using a Delta XP ThermoFisher isotope-ratio mass spectrometer interfaced with a Costech elemental analyser.…”

Section: Stable Isotope Analysismentioning

confidence: 99%

A Mechanistic Understanding of Polyethylene Biodegradation by the Marine Bacterium Alcanivorax

Zadjelovic

Erni-Cassola²,

Lester

et al. 2021

SSRN Journal

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“…are both capable of accumulating salt in leaf vacuoles and producing organic solutes, different types and concentrations of compatible solutes produced by each species may also affect osmotic potentials to different degrees (Popp et al, 1985). In addition, distinct compatible solutes produced by different species may have a larger impact on δ H lipid values than on δ 2 H water values, as types and varying proportions of compatible solutes in different salt marsh plants or mangrove species may result in varying contributions of hydrogen in alkanes and fatty acids from photosynthetic and metabolic NADPH pools (Ladd and Sachs, 2015a;Eley et al, 2018).…”

Section: Influence Of δ 2 H Lw On δ 2 H Fatty Acidmentioning

confidence: 99%

Hydrogen and carbon isotope responses to salinity in greenhouse-cultivated mangroves

Park

Ladd

Sachs

2019

Organic Geochemistry

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Paired hydrogen and carbon isotope ratios ( 2 H/ 1 H and 13 C/ 12 C) of mangrove lipids can be used to quantitatively reconstruct past salinity and 2 H/ 1 H ratios of environmental water, and in some cases precipitation rate. This approach is based on the observation that net 2 H-and 13 Cfractionation increases and decreases, respectively, with the salinity of environmental water. In order to better understand the mechanisms underlying these empirical observations and ultimately improve estimates of paleoprecipitation from the paired H and C isotope approach, we analyzed the isotopic composition of fatty acids from five species of mangroves cultivated in salinity treatments of 5-30 ppt (g/kg) for 3.5 years in a greenhouse. Decreased net 13 Cfractionation with salinity in three mangrove species was attributed to increased water use efficiency and thus a 13 C-enriched internal CO 2 pool. Net 2 H-fractionation decreased with salinity in three mangrove species, opposite to previous observations of mangroves growing along salinity gradients in lakes and estuaries. The difference between uncultivated and greenhouse-cultivated mangroves may result from variability of 2 H/ 1 H of environmental water in natural environments. In addition, increased net 2 H-fractionation with salinity could be due to temporal variability in 2 H/ 1 H of leaf water and timing of lipid production, and the use of stored carbohydrates in seeds. Due to the sensitivity of the salinity and 13 C-fractionation relationship for calculating both salinity and water isotopes, optimization of mangrove lipid H and C isotopes as a paleohydrologic tracer may be best achieved through laboratory-based calibrations of the relationship between 13 C-fractionation and salinity.

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Variation in Hydrogen Isotope Composition Among Salt Marsh Plant Organic Compounds Highlights Biochemical Mechanisms Controlling Biosynthetic Fractionation

Abstract: Hydrogen isotopes of plant-derived biomarkers can vary by >100‰ at a single location. Isotope

Cited by 9 publications

References 85 publications

Leaf wax n-alkane distribution and hydrogen isotopic fractionation in fen plant communities of two Mediterranean wetlands (Tenaghi Philippon, Nisí fen—Greece)

Leaf wax n-alkane distribution and hydrogen isotopic fractionation in fen plant communities of two Mediterranean wetlands (Tenaghi Philippon, Nisí fen—Greece)

A Mechanistic Understanding of Polyethylene Biodegradation by the Marine Bacterium Alcanivorax

Hydrogen and carbon isotope responses to salinity in greenhouse-cultivated mangroves

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