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  • 1
    Electronic Resource
    Electronic Resource
    Nature; 370.1994, 6490, S.549-552 (1994)
    [s.l.] : Nature Publishing Group
    Nature 370 (1994), S. 549-552 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sediment was collected with a box corer from the upper continental slope of the Washington coast, USA (46° 45.02' N, 124° 59.87 W; water depth 647m) in August 1993. The core was kept at 2 °C until sectioned (96 h) under N2 into 0.5- (top 2 cm) or 1.0-cm slices. 210Pb profiles of a ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/370549a0
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    Paper (German National Licenses)
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  • 2
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    14C Blank Assessment in Small-Scale Compound-Specific Radiocarbon Analysis of Lipid Biomarkers and Lignin Phenols (2020)
    Cambridge Univ. Press
    In:  Radiocarbon, 62 (1). pp. 207-218.
    Details
    Publication Date: 2021-05-04
    Description: Compound-specific radiocarbon (14C) dating often requires working with small samples of 〈 100 µg carbon (µgC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon (F14C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 µgC) of n-alkanoic acids and lignin phenols obtained from standard materials with known F14C values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown F14C. There is an inverse linear relationship between the measured F14C values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We use Bayesian methods to fit linear regression lines between F14C and 1/mass for the fossil and modern standards. The intersection points of these lines are used to infer F14Cblank and mblank and their associated uncertainties. We estimate 4.88 ± 0.69 μgC of procedural blank with F14C of 0.714 ± 0.077 for n-alkanoic acids, and 0.90 ± 0.23 μgC of procedural blank with F14C of 0.813 ± 0.155 for lignin phenols. These F14Cblank and mblank can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1017/RDC.2019.108
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    14C Blank Assessment in Small-Scale Compound-Specific Radiocarbon Analysis of Lipid Biomarkers and Lignin Phenols (2020)
    In:  EPIC3Radiocarbon, 62(1), pp. 207-218, ISSN: 0033-8222
    Details
    Publication Date: 2021-06-21
    Description: Compound-specific radiocarbon (14C) dating often requires working with small samples of 〈 100 μg carbon (μgC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon (F14C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 μgC) of n-alkanoic acids and lignin phenols obtained from standard materials with known F14C values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown F14C. There is an inverse linear relationship between the measured F14C values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We use Bayesian methods to fit linear regression lines between F14C and 1/mass for the fossil and modern standards. The intersection points of these lines are used to infer F14Cblank and mblank and their associated uncertainties. We estimate 4.88 ± 0.69 μgC of procedural blank with F14C of 0.714 ± 0.077 for n-alkanoic acids, and 0.90 ± 0.23 μgC of procedural blank with F14C of 0.813 ± 0.155 for lignin phenols. These F14Cblank and mblank can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 4
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    High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice cores (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L13501, doi:10.1029/2009GL037643.
    Description: Semi-volatile organic compounds derived from burned and fresh vascular plant sources and preserved in high-altitude ice fields were detected and identified through use of recently developed analytical tools. Specifically, stir bar sorptive extraction and thermal desorption coupled with gas chromatography/time-of-flight mass spectrometry allowed measurement of multiple biomarkers in small sample volumes (≤30 ml). Among other compounds of interest, several diterpenoids, which suggest inputs from conifers and conifer burning, were identified in post-industrial era and older Holocene ice from the Sajama site in the Bolivian Andes, but not in a glacial period sample, consistent with aridity changes. Differences in biomarker assemblages between sites support the use of these compounds as regionally constrained recorders of vegetation and climate change. This study represents the first application of these analytical techniques to ice core research and the first indication that records of vegetation fires may be reconstructed from diterpenoids in ice.
    Description: This project was supported in part by NSF-OCE (0402533), and NSF-EAR (0094475).
    Keywords: Biomass burning ; Molecular markers
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/postscript
    Format: application/pdf
    Format: text/plain
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  • 5
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    Radiocarbon dating of alkenones from marine sediments : II. Assessment of carbon process blanks (2011)
    Dept. of Geosciences, University of Arizona
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2005. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 47 (2005): 413-424.
    Description: We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone 14C dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the procedure does not lead to a systematic bias of the results of alkenone dating to either younger or older ages. Our results indicate that alkenones record Δ14C of ambient DIC with an accuracy of approximately 10‰. A conservative estimate of measurement precision is 17‰ for modern samples. Alkenone 14C ages are expected to be reliable within 500 yr for samples younger than 10,500 14C yr.
    Description: This research was funded by NSF grant # OCE-0327405 and DFG project # SCHN621 and a WHOI-NOSAMS postdoctoral scholarship to GM.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 6
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    Tracing river chemistry in space and time : dissolved inorganic constituents of the Fraser River, Canada (2014)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 124 (2014): 283-308, doi:10.1016/j.gca.2013.09.006.
    Description: The Fraser River basin in southwestern Canada bears unique geologic and climatic features which make it an ideal setting for investigating the origins, transformations and delivery to the coast of dissolved riverine loads under relatively pristine conditions. We present results from sampling campaigns over three years which demonstrate the lithologic and hydrologic controls on fluxes and isotope compositions of major dissolved inorganic runoff constituents (dissolved nutrients, major and trace elements, 87Sr/86Sr, δD). A time series record near the Fraser mouth allows us to generate new estimates of discharge-weighted concentrations and fluxes, and an overall chemical weathering rate of 32 t km-2 y-1. The seasonal variations in dissolved inorganic species are driven by changes in hydrology, which vary in timing across the basin. The time series record of dissolved 87Sr/86Sr is of particular interest, as a consistent shift between higher (“more radiogenic”) values during spring and summer and less radiogenic values in fall and winter demonstrates the seasonal variability in source contributions throughout the basin. This seasonal shift is also quite large (0.709 – 0.714), with a discharge-weighted annual average of 0.7120 (2 s.d. = 0.0003). We present a mixing model which predicts the seasonal evolution of dissolved 87Sr/86Sr based on tributary compositions and water discharge. This model highlights the importance of chemical weathering fluxes from the old sedimentary bedrock of headwater drainage regions, despite their relatively small contribution to the total water flux.
    Description: This work was supported by the WHOI Academic Programs Office and MIT PAOC Houghton Fund to BMV, a WHOI Arctic Research Initiative grant to ZAW, NSF-ETBC grant OCE-0851015 to BPE and TIE, and NSF grant EAR-1226818 to BPE.
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
    Format: application/vnd.ms-excel
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  • 7
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    Multi-molecular tracers of terrestrial carbon transfer across the pan-Arctic : comparison of hydrolyzable components with plant wax lipids and lignin phenols (2015)
    Copernicus Publications on behalf of the European Geosciences Union
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 12 (2015): 4841-4860, doi:10.5194/bg-12-4841-2015.
    Description: Hydrolyzable organic carbon (OC) comprises a significant component of sedimentary particulate matter transferred from land into oceans via rivers. Its abundance and nature are however not well studied in Arctic river systems, and yet may represent an important pool of carbon whose fate remains unclear in the context of mobilization and related processes associated with a changing climate. Here, we examine the molecular composition and source of hydrolyzable compounds isolated from sedimentary particles derived from nine rivers across the pan-Arctic. Bound fatty acids (b-FAs), hydroxy FAs, n-alkane-α,ω-dioic acids (DAs) and phenols were the major components released upon hydrolysis of these sediments. Among them, b-FAs received considerable inputs from bacterial and/or algal sources, whereas ω-hydroxy FAs, mid-chain substituted acids, DAs, and hydrolyzable phenols were mainly derived from cutin and suberin of higher plants. We further compared the distribution and fate of suberin- and cutin-derived compounds with those of other terrestrial biomarkers (plant wax lipids and lignin phenols) from the same Arctic river sedimentary particles and conducted a benchmark assessment of several biomarker-based indicators of OC source and extent of degradation. While suberin-specific biomarkers were positively correlated with plant-derived high-molecular-weight (HMW) FAs, lignin phenols were correlated with cutin-derived compounds. These correlations suggest that, similar to leaf-derived cutin, lignin was mainly derived from litter and surface soil horizons, whereas suberin and HMW FAs incorporated significant inputs from belowground sources (roots and deeper soil). This conclusion is supported by the negative correlation between lignin phenols and the ratio of suberin-to-cutin biomarkers. Furthermore, the molecular composition of investigated biomarkers differed between Eurasian and North American Arctic rivers: while lignin dominated in the terrestrial OC of Eurasian river sediments, hydrolyzable OC represented a much larger fraction in the sedimentary particles from Colville River. Hence, studies exclusively focusing on either plant wax lipids or lignin phenols will not be able to fully unravel the mobilization and fate of bound OC in Arctic rivers. More comprehensive, multi-molecular investigations are needed to better constrain the land–ocean transfer of carbon in the changing Arctic, including further research on the degradation and transfer of both free and bound components in Arctic river sediments.
    Description: X. Feng acknowledges support from the Chinese National Key Development Program for Basic Research (2014CB954003, 2015CB954201). The ISSS program is supported by the Knut and Alice Wallenberg Foundation, headquarters of the Russian Academy of Sciences, the Swedish Research Council, the US National Oceanic and Atmospheric Administration, the Russian Foundation of Basic Research (#13-05-12028, 13-05-12041), the Swedish Polar Research Secretariat and the Nordic Council of Ministers (Arctic Co-Op and TRI-DEFROST programs). Collection of the Mackenzie sediment samples was supported by Fisheries and Oceans Canada and Indian and Northern Affairs Canada as part of the NOGAP B.6 project. Ö. Gustafsson acknowledges an Academy Research Fellow grant from the Swedish Royal Academy of Sciences. I. P. Semiletov and O. V. Dudarev thank the Government of the Russian Federation (#2013-220-04-157) for support as well as A. I. Khanchuk personally. T. I. Eglinton acknowledges support from Swiss National Science foundation (SNF) grant no. 200021_140850, and grants OCE-9907129, OCE-0137005, and OCE-0526268 from the US National Science Foundation (NSF), the Stanley Watson Chair for Excellence in Oceanography, and ETH Zurich. J. E. Vonk is thankful for support from NWO Rubicon (#825.10.022) and Veni (#863.12.004). B. E. van Dongen is thankful for support from the UK NERC (NE/I024798/1). R. M. Holmes acknowledges support from NSF 0436118, NSF 0732555, and NSF 1107774. X. Feng thanks WHOI for a postdoctoral scholar fellowship and for postdoctoral support from ETH Zurich.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 8
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    Radiocarbon dating of alkenones from marine sediments : I. Isolation protocol (2011)
    Dept. of Geosciences, University of Arizona
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2005. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 47 (2005): 401-412.
    Description: The chemical and isotopic compositions of long-chain (C36–C39) unsaturated ketones (alkenones), a unique class of algal lipids, encode surface ocean properties useful for paleoceanographic reconstruction. Recently, we have sought to extend the utility of alkenones as oceanic tracers through measurement of their radiocarbon contents. Here, we describe a method for isolation of alkenones from sediments as a compound class based on a sequence of wet chemical techniques. The steps involved, which include silica gel column chromatography, urea adduction, and silver nitrate-silica gel column chromatography, exploit various structural attributes of the alkenones. Amounts of purified alkenones estimated by GC/FID measurements were highly correlated with CO2 yields after sample combustion, indicating purities of greater than 90% for samples containing ≥100 μg C. The degree of alkenone unsaturation ( ) also varied minimally through the procedure. We also describe a high-performance liquid chromatography (HPLC) method to isolate individual alkenones for molecular-level structural and isotopic determination.
    Description: This work was funded through grants from the National Science Foundation (OCE-9809624; OCE- 9907129) and the Japan Society for the Promotion of Science.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 9
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    14C and 13C characteristics of higher plant biomarkers in Washington margin surface sediments (2013)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 105 (2013): 14-30, doi:10.1016/j.gca.2012.11.034.
    Description: Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their 13C and 14C compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial carbon in marine environment. In this study, we describe a revised method of isolating individual lignin phenols from complex sedimentary matrices for 14C analysis using high pressure liquid chromatography (HPLC) and compare this approach to a method utilizing preparative capillary gas chromatography (PCGC). We then examine in detail the 13C and 14C compositions of plant wax lipids and lignin phenols in sediments from the inner and mid shelf of the Washington margin that are influenced by discharge of the Columbia River. Plant wax lipids (including n-alkanes, n-alkanoic (fatty) acids, n-alkanols, and n-aldehydes) displayed significant variability in both δ13C (-28.3 to -37.5 ‰) and ∆14C values (-204 to +2 ‰), suggesting varied inputs and/or continental storage and transport histories. In contrast, lignin phenols exhibited similar δ13C values (between -30 to -34 ‰) and a relatively narrow range of ∆14C values (-45 to -150 ‰; HPLC-based mesurement) that were similar to, or younger than, bulk OM (-195 to -137 ‰). Moreover, lignin phenol 14C age correlated with the degradation characteristics of this terrestrial biopolymer in that vanillyl phenols were on average ~500 years older than syringyl and cinnamyl phenols that degrade faster in soils and sediments. The isotopic characteristics, abundance, and distribution of lignin phenols in sediments suggest that they serve as promising tracers of recently biosynthesized terrestrial OM during supply to, and dispersal within the marine environment. Lignin phenol 14C measurements may also provide useful constraints on the vascular plant end member in isotopic mixing models for carbon source apportionment, and for interpretation of sedimentary records of past vegetation dynamics. Key words: 14C and 13C composition, radiocarbon age, plant wax lipids, lignin phenols, Washington margin, marine carbon cycling, terrestrial organic matter
    Description: Grants OCE-9907129, OCE-0137005, and OCE-0526268 (to TIE) from the National Science Foundation (NSF) supported this research.
    Keywords: 14C and 13C composition ; Radiocarbon age ; Plant wax lipids ; Lignin phenols ; Washington margin ; Marine carbon cycling ; Terrestrial organic matter
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 10
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    Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic : 14C characteristics of sedimentary carbon components and their environmental controls (2016)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 29 (2015): 1855–1873, doi:10.1002/2015GB005204.
    Description: Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular 14C measurements, including novel analyses of suberin- and/or cutin-derived diacids (DAs) and hydroxy fatty acids (FAs), we compared the radiocarbon characteristics of a comprehensive suite of terrestrial markers (including plant wax lipids, cutin, suberin, lignin, and hydroxy phenols) in the sedimentary particles from nine major arctic and subarctic rivers in order to establish a benchmark assessment of the mobilization patterns of terrestrial OC pools across the pan-Arctic. Terrestrial lipids, including suberin-derived longer-chain DAs (C24,26,28), plant wax FAs (C24,26,28), and n-alkanes (C27,29,31), incorporated significant inputs of aged carbon, presumably from deeper soil horizons. Mobilization and translocation of these “old” terrestrial carbon components was dependent on nonlinear processes associated with permafrost distributions. By contrast, shorter-chain (C16,18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in 14C, suggesting incorporation of relatively young carbon supplied by runoff processes from recent vegetation debris and surface layers. Furthermore, the radiocarbon content of terrestrial markers is heavily influenced by specific OC sources and degradation status. Overall, multitracer molecular 14C analysis sheds new light on the mobilization of terrestrial OC from arctic watersheds. Our findings of distinct ages for various terrestrial carbon components may aid in elucidating fate of different terrestrial OC pools in the face of increasing arctic permafrost thaw.
    Description: Chinese National Key Development Program for Basic Research Grant Numbers: 2014CB954003, 2015CB954201; Knut and Alice Wallenberg Foundation; Headquarters of the Russian Academy of Sciences; Swedish Research Council; US National Oceanic and Atmospheric Administration; Russian Foundation of Basic Research Grant Numbers: (13-05-12028, 13-05-12041; Swedish Polar Research Secretariat; Nordic Council of Ministers; Government of the Russian Federation Grant Number: 2013-220-04-157; Swiss National Science foundation. Grant Number: (200021_140850 US National Science Foundation (NSF) Grant Numbers: OCE-9907129, OCE-0137005, OCE-0526268; Stanley Watson Chair for Excellence in Oceanography Grant Number: 825.10.022; ETH Zürich; NWO Rubicon; Veni Grant Number: 863.12.004; UK NERC Grant Number: NE/I024798/1; NSF. Grant Numbers: 0436118, 0732555, 1107774
    Description: 2016-05-02
    Keywords: Compound-specific radiocarbon analysis ; Terrestrial carbon markers ; Pan-arctic rivers ; Diacids ; Lignin ; Plant wax lipids
    Repository Name: Woods Hole Open Access Server
    Type: Article
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