Hydrogen isotope fractionation in modern plants along a boreal-tundra transect in Alaska

O'Connor, Keith; Berke, Melissa A.; Ziolkowski, Lori A.

doi:10.1016/j.orggeochem.2020.104064

Cited by 16 publications

(7 citation statements)

References 105 publications

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“…The long-chain n-alkanes (n-alkanoic acids, n-alcohols) with 27 to 35 carbon atoms are biomarkers of terrestrial higher plants (Eglinton and Hamilton, 1967). Indeed, long-chain (C27-C33) n-alkanes are predominantly derived from higher terrestrial plants in the El'gygytgyn catchment (Wilkie et al, 2013), similar to observations at other Arctic locations (Daniels et al, 2017;O'Connor et al, 2020). Over the MPT study interval, CPI values average 3.6 indicating that higher plant inputs dominate the n-alkane pool.…”

Section: Interpretation Of the N-alkane Acl Recordsupporting

confidence: 61%

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Lindberg

Daniels

Castañeda

et al. 2021

Preprint

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Abstract. The Mid-Pleistocene Transition (MPT) is a widely recognized global climate shift occurring between approximately 1,250 to 700 ka. At this time, Earth's climate underwent a major transition from dominant 40 kyr glacial-interglacial cycles to quasi-100 kyr cycles. The cause of the MPT remains a puzzling aspect of Pleistocene climate. Presently, there are few, if any, continuous MPT records from the Arctic yet understanding the role and response of the high latitudes to the MPT is required to better evaluate the causes of this climatic shift. Here, we present new continental biomarker records of temperature and vegetation spanning 1,142 to 752 ka from Lake El'gygytgyn (Far East Russia). We reconstruct warm-season temperature variations across the MPT based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) using the MBTʹ5ME proxy. The new Arctic temperature record does not display an overall cooling trend during the MPT but does exhibit strong glacial-interglacial cyclicity. Spectral analysis demonstrates persistent obliquity and precession pacing over the study interval and reveals substantial sub-orbital temperature variations at ~900 kyr during the first “skipped” interglacial. Interestingly, Marine Isotope Stage (MIS) 31, which is widely recognized as a particularly warm interglacial, does not exhibit exceptional warmth at Lake El'gygytgyn. Instead, we find that MIS 29, 27 and 21 were as warm or warmer than MIS 31. In particular, MIS 21 (~870 to 820 ka) stands out as an especially warm and long interglacial in the continental Arctic while MIS 25 is a notably cold interglacial. Throughout the MPT, Lake El'gygytgyn pollen data exhibits a long-term drying trend, with a shift to an increasingly open landscape noted after around 900 ka (Zhao et al., 2018), which is also reflected in our higher plant leaf wax (n-alkane) distributions. Although the mechanisms driving the MPT remain a matter of debate, our new climate records from the continental Arctic exhibit some similarities to changes noted around the North Pacific region. Overall, the new organic geochemical data from Lake El'gygytgyn contribute to expanding our knowledge of the high-latitude response to the MPT.

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Section: Interpretation Of the N-alkane Acl Recordsupporting

confidence: 61%

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Lindberg

Daniels

Castañeda

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The long-chain n-alkanes (n-alkanoic acids, n-alcohols) with 27 to 35 carbon atoms are biomarkers of terrestrial higher plants (Eglinton and Hamilton, 1967). Indeed, long-chain (C 27 -C 33 ) n-alkanes are predominantly derived from higher terrestrial plants in the El'gygytgyn catchment , similar to observations at other Arctic locations (Daniels et al, 2017;O'Connor et al, 2020). Over the MPT study interval, CPI values average 3.6 indicating that higher plant inputs dominate the n-alkane pool (Fig.…”

Section: Interpretation Of the N-alkane Acl Recordsupporting

confidence: 54%

Biomarker proxy records of Arctic climate change during the Mid-Pleistocene transition from Lake El'gygytgyn (Far East Russia)

et al. 2022

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Abstract. The Mid-Pleistocene Transition (MPT) is a widely recognized global climate shift occurring between approximately 1250 and 700 ka. At this time, Earth's climate underwent a major transition from dominant 40 kyr glacial–interglacial cycles to quasi-100 kyr cycles. The cause of the MPT remains a puzzling aspect of Pleistocene climate. Presently, there are few, if any, continuous MPT records from the Arctic, yet understanding the role and response of the high latitudes to the MPT is required to better evaluate the causes of this climatic shift. Here, we present new continental biomarker records of temperature and vegetation spanning 1142 to 752 ka from Lake El'gygytgyn (Far East Russia). We reconstruct warm-season temperature variations across the MPT based on branched glycerol dialkyl glycerol tetraethers (brGDGTs). The new Arctic temperature record does not display an overall cooling trend during the MPT but does exhibit strong glacial–interglacial cyclicity. Spectral analysis demonstrates persistent obliquity and precession pacing over the study interval and reveals substantial sub-orbital temperature variations at ∼900 ka during the first “skipped” interglacial. Interestingly, Marine Isotope Stage (MIS) 31, which is widely recognized as a particularly warm interglacial, does not exhibit exceptional warmth in the Lake El'gygytgyn brGDGT record. Instead, we find that MIS 29, 27, and 21 were as warm or warmer than MIS 31. In particular, MIS 21 (∼870 to 820 ka) stands out as an especially warm and long interglacial in the continental Arctic while MIS 25 is a notably cold interglacial. Throughout the MPT, Lake El'gygytgyn pollen data exhibit a long-term drying trend, with a shift to an increasingly open landscape noted after around 900 ka (Zhao et al., 2018), which is also reflected in our higher plant leaf wax (n-alkane) distributions. Although the mechanisms driving the MPT remain a matter of debate, our new climate records from the continental Arctic exhibit some similarities to changes noted around the North Pacific region. Overall, the new organic geochemical data from Lake El'gygytgyn contribute to expanding our knowledge of the high-latitude response to the MPT.

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“…Due to changes in sediment and n-alkanoic acid sources discussed above (see Results), we only interpret the leaf wax record from 5.8 ka to the present. Moreover, apparent fractionation (ε app ) values for important terrestrial plant taxa within the Lake QPT catchment, compiled from other mid-and high-latitude regions (Hou et al, 2007;Gao et al, 2014;Daniels et al, 2017;Dion-Kirschner et al, 2020;O'Connor et al, 2020), are broadly similar (ε app Shrubs = −93 ± 17‰, n = 37; ε app Herbs, including graminoids = −96 ± 29‰, n = 9; Supporting Information, Table S1), suggesting that a change in the relative abundance of major plant species in the QPT catchment would not influence the QPT δ 2 H records simply via differences in apparent fractionation. Because the mid-to late Holocene terrestrial plant community was relatively stable at Lake QPT and apparent fractionation factors of dominant plants in the catchment are similar, the n-alkanoic acid plant wax δ 2 H values at Lake QPT probably primarily reflect changes in mean annual precipitation δ 2 H, but we cannot completely exclude the possibility that vegetation shifts affect the plant wax δ 2 H signal to some degree.…”

Section: Speciesmentioning

confidence: 99%

Southern Baffin Island mean annual precipitation isotopes modulated by summer and autumn moisture source changes during the past 5800 years

Gorbey

Thomas

Crump

et al. 2021

J Quaternary Science

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Paleo water isotope records can elucidate how the Arctic water cycle responded to past climate changes. We analyze the hydrogen isotope composition (δ2H) of plant‐derived n‐alkanoic acids (waxes) from Lake Qaupat, Baffin Island, Nunavut, Canada, to assess moisture sources and seasonality during the past 5.8 ka. We compare this record to a sedimentary ancient DNA (sedaDNA)‐inferred vascular plant record from the same lake, aiming to overcome the uncertainty of plant community impacts on leaf waxes. As the sedaDNA record reveals a stable plant community after the colonization of Betula sp. at 6.1 ka, we interpret plant wax δ2H values to reflect climate, specifically mean annual precipitation δ2H. However, the distributions of n‐alkanoic acid homologs suggest that aquatic mosses, which are not represented in the sedaDNA record, may become more abundant towards the present. Therefore, we cannot exclude the possibility that changes in the plant community cause changes in the plant wax δ2H record, particularly long‐chain waxes, which become less abundant through this record. We find that Lake Qaupat mid‐chain plant wax δ2H is enriched coincident with high Labrador Sea summer surface temperature, which suggests that local moisture sources in summer and early autumn have the greatest impact on precipitation isotopes in this region.

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Hydrogen isotope fractionation in modern plants along a boreal-tundra transect in Alaska

Cited by 16 publications

References 105 publications

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Biomarker Proxy Records of Arctic Climate Change During the Mid-Pleistocene Transition from Lake El’gygytgyn (Far East Russia)

Biomarker proxy records of Arctic climate change during the Mid-Pleistocene transition from Lake El'gygytgyn (Far East Russia)

Southern Baffin Island mean annual precipitation isotopes modulated by summer and autumn moisture source changes during the past 5800 years

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