Influence of plant growth form, habitat and season on leaf-wax n-alkane hydrogen-isotopic signatures in equatorial East Africa

Griepentrog, Marco; Wispelaere, Lien De; Bauters, Marijn; Bodé, Samuel; Hemp, Andreas; Verschuren, Dirk; Boeckx, Pascal

doi:10.1016/j.gca.2019.08.004

Cited by 27 publications

(15 citation statements)

References 79 publications

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“…Modern Indian grasses produce higher proportions of C 33 and C 35 n-alkanes while trees and shrubs produce more C 27 and C 29 (Figure S5, Section S1.6.1) (Ankit et al, 2017;Sarkar et al, 2014); similar patterns are also documented for grasses in Africa (Figure S6) (Ali et al, 2005;Badewien et al, 2015;Bezabih et al, 2011;Garcin et al, 2014;Griepentrog et al, 2019;Kristen et al, 2010;Magill et al, 2019;Rommerskirchen et al, 2006;Vogts et al, 2009), North America, and Australia (Andrae et al, 2018;Bush & McInerney, 2013;Howard et al, 2018). Consistent with plant-type lipid patterns, the proportion of C 4 grasses in an ecosystem is reflected in the greater sedimentary abundance of C 33 and C 35 (Garcin et al, 2012(Garcin et al, , 2014.…”

Section: Sourcing N-alkanes Via Distribution and Carbon Isotope Signaturessupporting

confidence: 53%

Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent

Polissar

Uno

Phelps

et al. 2021

Paleoceanog and Paleoclimatol

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During the Cenozoic (66 Ma to present), grasslands and open habitats replaced forests across large swaths of the tropics and subtropics (Jacobs et al., 1999;Strömberg, 2011), reshaping the vegetation structure and faunal communities in terrestrial ecosystems around the world (Anderson, 2006). In many regions, the late Miocene (∼11-5 Ma) conclusion of this ecological trajectory was the establishment of grasslands dominated by grass species using the C 4 photosynthetic pathway (Edwards et al., 2010). A substantial number of studies have mapped out when C 4 ecosystems became established around the globe. The earliest onset of C 4 ecosystem expansion occurred around 10

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Section: Sourcing N-alkanes Via Distribution and Carbon Isotope Signaturessupporting

confidence: 53%

Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent

Polissar

Uno

Phelps

et al. 2021

Paleoceanog and Paleoclimatol

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“…During biosynthesis, ε bio leads to 2 H depletion of ∼−160 in δ 2 H n-alkane values and 18 O enrichment of ∼+27 in δ 18 O sugar values. At the same time, it is reported that ε bio can vary among plant life forms and plant physiological metabolisms, for different environmental conditions and latitudes, as well as through relative contributions of the strongly depleted NADPH pool (Sessions et al, 1999;Kahmen et al, 2013b;Newberry et al, 2015;Liu et al, 2016;Sessions, 2016;Lehmann et al, 2017;Cormier et al, 2018;Griepentrog et al, 2019;Liu and An, 2019). The apparent fractionation (ε 2H n-alkane/p , ε 18O sugar/p ), i.e., the difference between the isotopic signature of precipitation/source water (δ 2 H p and δ 18 O p ) and δ 2 H n-alkane and δ 18 O sugar , respectively, basically integrates over ε SW , ε Et and ε bio and results in 2 H-depleted leaf wax-derived n-alkanes but 18 Oenriched hemicellulose-derived sugars relative to δ 2 H p and δ 18 O p (Sachse et al, 2012;Tuthorn et al, 2015;Daniels et al, 2017;Liu and An, 2019;Strobel et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Leaf Waxes and Hemicelluloses in Topsoils Reflect the δ2H and δ18O Isotopic Composition of Precipitation in Mongolia

et al. 2020

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Compound-specific hydrogen and oxygen isotope analyzes on leaf wax-derived n-alkanes (δ 2 H n-alkane) and the hemicellulose-derived sugar arabinose (δ 18 O ara) are valuable, innovative tools for paleohydrological reconstructions. Previous calibration studies have revealed that δ 2 H n-alkane and δ 18 O ara reflect the isotopic composition of precipitation, but-depending on the region-may be strongly modulated by evapotranspirative enrichment. Since no calibration studies exist for semi-arid and arid Mongolia so far, we have analyzed δ 2 H n-alkane and δ 18 O ara in topsoils collected along a transect through Mongolia, and we compared these values with the isotopic composition of precipitation (δ 2 H p-WM and δ 18 O p-WM , modeled data) and various climate parameters. δ 2 H n-alkane and δ 18 O ara are more positive in the arid southeastern part of our transect, which reflects the fact that also the precipitation is more enriched in 2 H and 18 O along this part of the transect. The apparent fractionation ε app , i.e., the isotopic difference between precipitation and the investigated compounds, shows no strong correlation with climate along the transect (ε 2H n-C29/p = −129 ± 14 , ε 2H n-C31/p = −146 ± 14 , and ε 18O ara/p = +41 ± 2). Our results suggest that δ 2 H n-alkane and δ 18 O ara in topsoils from Mongolia reflect the isotopic composition of precipitation and are not strongly modulated by climate. Correlation with the isotopic composition of precipitation has root-mean-square errors of 13.4 for δ 2 H n-C29 , 12.6 for δ 2 H n-C31 , and 1.2 for δ 18 O ara , so our findings corroborate the great potential of compound-specific δ 2 H n-alkane and δ 18 O ara analyzes for paleohydrological research in Mongolia.

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“…The hydrogen from rainfall is incorporated into terrestrial plant epicuticular waxes, resulting in a demonstrable correlation between terrestrial plant δD wax and precipitation δD values (e.g., Huang et al., 2004; Sachse et al., 2004), despite an offset in δD wax due to isotopic fractionations from biosynthesis and evaporative processes. In the tropics, there is a strong relationship between δD values and precipitation amount (Dansgaard, 1964; Rozanski et al., 1993), and plant waxes from south Africa predominantly record the δD values of their source waters (Griepentrog et al., 2019; Herrmann et al., 2017). As such, we interpret more positive (negative) values to indicate more (less) arid conditions due to tropical rainfall amount.…”

Section: Resultsmentioning

confidence: 99%

Plio‐Pleistocene Continental Hydroclimate and Indian Ocean Sea Surface Temperatures at the Southeast African Margin

Taylor

Berke

Castañeda

et al. 2021

Paleoceanog and Paleoclimatol

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The Plio-Pleistocene encompasses large-scale changes in climate and may provide an analog for the function of Earth's ecosystems in a high carbon dioxide (CO 2) world. Pliocene climate was characterized by atmospheric CO 2 levels similar to today, reduced sea surface temperature (SST) gradients, and events such as the restriction of the Central American and Indonesian Seaways (Cane & Molnar, 2001; Fedorov et al., 2013). Despite its relative warmth and stability, the Pliocene is defined by long-term cooling that is potentially related to tectonic plate movement and consequent changes in ocean currents and pCO 2 drawdown, especially in the Indo-Pacific region (Cane & Molnar, 2001). The Plio-Pleistocene transition around 2.7 Ma is marked by the breakdown of Pliocene climate conditions, as strong SST gradients between the high-and low-latitudes and across the Pacific Ocean basin were established, and Northern Hemisphere glaciation intensified (Fedorov et al., 2013). The development of stronger zonal SST gradients in the Pacific Ocean was likely related to gradual thermocline shoaling in the Pliocene and an increase in tropical upwelling that led to strengthened Walker circulation (Ravelo et al., 2004). The interaction between these ocean-atmosphere feedbacks and changes in insolation potentially magnified the climate's sensitivity to obliquity, leading to the 41 kyr pacing of higher amplitude glacial cycles in the early Pleistocene (Ravelo et al., 2004).

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Influence of plant growth form, habitat and season on leaf-wax n-alkane hydrogen-isotopic signatures in equatorial East Africa

Cited by 27 publications

References 79 publications

Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent

Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent

Leaf Waxes and Hemicelluloses in Topsoils Reflect the δ2H and δ18O Isotopic Composition of Precipitation in Mongolia

Plio‐Pleistocene Continental Hydroclimate and Indian Ocean Sea Surface Temperatures at the Southeast African Margin

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Influence of plant growth form, habitat and season on leaf-wax n-alkane hydrogen-isotopic signatures in equatorial East Africa

Cited by 27 publications

References 79 publications

Hydrologic Changes Drove the Late Miocene Expansion of C4 Grasslands on the Northern Indian Subcontinent

Hydrologic Changes Drove the Late Miocene Expansion of C4 Grasslands on the Northern Indian Subcontinent

Leaf Waxes and Hemicelluloses in Topsoils Reflect the δ2H and δ18O Isotopic Composition of Precipitation in Mongolia

Plio‐Pleistocene Continental Hydroclimate and Indian Ocean Sea Surface Temperatures at the Southeast African Margin

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Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent

Hydrologic Changes Drove the Late Miocene Expansion of C₄ Grasslands on the Northern Indian Subcontinent