Comparisons of lipid molecular and carbon isotopic compositions in two particle-size fractions from surface peat and their implications for lipid preservation

Wang, Xinxin; Huang, Xianyu; Sachse, Dirk; Hu, Yu; Xue, Jinzhuang; Meyers, Philip A

doi:10.1007/s12665-016-5960-3

Cited by 11 publications

(5 citation statements)

References 52 publications

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“…Preferential postdepositional degradation of fresher and more labile nonmineral-associated OM in river sediments could also explain the lower TOC values and lower TOC and LCFA D 14 C values (older ages) of river sediments. However, since LCFA d 13 C values show no indication for enrichment due to degradation (Li et al, 2017;Wang et al, 2016), suggesting a similar origin for LCFAs in SPM and river sediments, we suspect that preferential transport and deposition of mineral-associated LCFAs is the most likely explanation. The lower ACL values for SPM than river sediments are the only indication of additional sources of n-C 24 -FAs to SPM, whereas brGDGT proxy values (BIT, #rings tetra ) are very comparable.…”

Section: Comparison Of Spm To River Sedimentsmentioning

confidence: 91%

Constraining Instantaneous Fluxes and Integrated Compositions of Fluvially Discharged Organic Matter

Freymond

Lupker

Peterse

et al. 2018

Geochem Geophys Geosyst

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Fluvial export of organic carbon (OC) and burial in ocean sediments comprises an important carbon sink, but fluxes remain poorly constrained, particularly for specific organic components. Here OC and lipid biomarker contents and isotopic characteristics of suspended matter determined in depth profiles across an active channel close to the terminus of the Danube River are used to constrain instantaneous OC and biomarker fluxes and integrated compositions during high to moderate discharges. During high (moderate) discharge, the total Danube exports 8 (7) kg/s OC, 7 (3) g/s higher plant‐derived long‐chain fatty acids (LCFA), 34 (21) g/s short‐chain fatty acids (SCFA), and 0.5 (0.2) g/s soil bacterial membrane lipids (brGDGTs). Integrated stable carbon isotopic compositions were TOC: −28.0 (−27.6)‰, LCFA: −33.5 (−32.8)‰ and Δ14C TOC: −129 (−38)‰, LCFA: −134 (−143)‰, respectively. Such estimates will aid in establishing quantitative links between production, export, and burial of OC from the terrestrial biosphere.

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Section: Comparison Of Spm To River Sedimentsmentioning

confidence: 91%

Constraining Instantaneous Fluxes and Integrated Compositions of Fluvially Discharged Organic Matter

Freymond

Lupker

Peterse

et al. 2018

Geochem Geophys Geosyst

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“…Previous 13 C incubation studies have proven that warming can substantially alter the stability of SOM. , Hence, this suggests that long-chain n -alkyl molecules in soils may undergo specific indirect isotopic modification during accelerated microbial biodegradation associated with induced climate change (i.e., changes in the degradation of biomass inputs) . In fact, microbial degradation of long-chain n -alkanes is not a rare phenomenon in natural settings due to heterotrophic reworking during degradation. , …”

Section: Resultsmentioning

confidence: 99%

“…77 In fact, microbial degradation of long-chain n-alkanes is not a rare phenomenon in natural settings due to heterotrophic reworking during degradation. 78,79 Comparison between δ 13 C of long-chain n-alkanes (C 27 , C 29 , and C 31 ) from biomass debris (Figure S1) and those identified from SOM was not significantly different under the two habitats or the climatic treatments. This supports the idea that the isotopic composition of the n-alkanes can be attributed to the contributions of biomass from each habitat.…”

Section: Isotopic Composition (δmentioning

confidence: 99%

Effects of Climate Change on Soil Organic Matter C and H Isotope Composition in a Mediterranean Savannah (Dehesa): An Assessment Using Py-CSIA

San-Emeterio,

Zavala,

Jiménez-Morillo

et al. 2023

Environ. Sci. Technol.

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Dehesas are Mediterranean agro-sylvo-pastoral systems sensitive to climate change. Extreme climate conditions forecasted for Mediterranean areas may change soil C turnover, which is of relevance for soil biogeochemistry modeling. The effect of climate change on soil organic matter (SOM) is investigated in a field experiment mimicking environmental conditions of global change scenarios (soil temperature increase, +2–3 °C, W; rainfall exclusion, 30%, D; a combination of both, W+D). Pyrolysis-compound-specific isotope analysis (Py-CSIA) is used for C and H isotope characterization of SOM compounds and to forecast trends exerted by the induced climate shift. After 2.5 years, significant δ13C and δ2H isotopic enrichments were detected. Observed short- and mid-chain n-alkane δ13C shifts point to an increased microbial SOM reworking in the W treatment; a 2H enrichment of up to 40‰ of lignin methoxyphenols was found when combining W+D treatments under the tree canopy, probably related to H fractionation due to increased soil water evapotranspiration. Our findings indicate that the effect of the tree canopy drives SOM dynamics in dehesas and that, in the short term, foreseen climate change scenarios will exert changes in the SOM dynamics comprising the biogeochemical C and H cycles.

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“…After cultivation, the CPI AF≥20 values of sand fractions in all TP soils depths showed a higher degree of degradation compared to corresponding fractions in NS (Figure 4), while the carbon content of TP sand fractions showed an increasing trend compared to that of NS (Figure 5). Generally, the coarser fractions contained inputs of fresher OM [38]. Although a continuous input of fresh biomass is expected during cultivation, intensive agricultural activities (plowing and fertilizing) may have promoted the degradation of SOM after exposure to oxygen, especially in the presence of reactive Fe [6,39].…”

Section: The Degradation Of Mineral-protected Lipidsmentioning

confidence: 99%

Conversion of Natural Soil to Paddy Promotes Soil Organic Matter Degradation in Small-Particle Fractions: δ13C and Lipid Biomarker Evidence

Li,

Zhang

et al. 2024

Agronomy

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The stabilization mechanism of soil organic matter (SOM) has received considerable attention. It is widely accepted that mineral sorption/protection is important for SOM stabilization. However, it remains unclear which organic carbon component is beneficial for mineral protection. We collected soil samples from a paddy field (TP) to compare with natural soil (NS). To illustrate the behavior of different SOM pools and their protection by particles, we separated the soils into different particle-size fractions and then removed the active minerals using an acid mixture (1 M HCl/10% HF). The different carbon pools were analyzed using stable carbon isotopes and lipid biomarkers. Our study showed that acid treatment evidently increased the extractability of free lipids, usually over 60%, which confirmed the predominant role of minerals in SOM protection. For NS, the δ13C values increased with decreasing soil particle sizes and soil depths, indicating that 13C-enriched SOM was selectively preserved. However, this trend disappeared after cultivation, which was mainly attributed to the combined effects of the input of 13C-depleted fresh SOM and decomposition of the preserved 13C-enriched SOM. Meanwhile, based on the degradation parameters of the overall lipid biomarkers, SOM showed higher degradation states in clay and silt fractions than in the sand fraction before cultivation. It is possible that the small particle-size fractions could selectively absorb highly degraded SOM. The clay-associated SOM showed a low degradation state, but its carbon content was low after cultivation. We propose that the previously protected SOM was degraded after cultivation and was replaced by relatively fresh SOM, which should be carefully monitored during SOM management.

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Comparisons of lipid molecular and carbon isotopic compositions in two particle-size fractions from surface peat and their implications for lipid preservation

Cited by 11 publications

References 52 publications

Constraining Instantaneous Fluxes and Integrated Compositions of Fluvially Discharged Organic Matter

Constraining Instantaneous Fluxes and Integrated Compositions of Fluvially Discharged Organic Matter

Effects of Climate Change on Soil Organic Matter C and H Isotope Composition in a Mediterranean Savannah (Dehesa): An Assessment Using Py-CSIA

Conversion of Natural Soil to Paddy Promotes Soil Organic Matter Degradation in Small-Particle Fractions: δ13C and Lipid Biomarker Evidence

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