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139 results on '"YUNKER, MARK B."'

6. Polycyclic aromatic hydrocarbon composition and potential sources for sediment samples from the Beaufort and Barents Seas

Author

Yunker, Mark B., Snowdon, Lloyd R., MacDonald, Robie W., Smith, John N., Fowler, Martin G., Skibo, Donald N., McLaughlin, Fiona A., Danyushevskaya, A.I., Petrova, V.I., and Ivanov, G.I.

Subjects
Beaufort Sea -- Environmental aspects, Barents Sea -- Environmental aspects, Polycyclic aromatic hydrocarbons -- Research, Marine sediments -- Microbiology, Environmental issues, Science and technology
Abstract

Distributions of polycyclic aromatic hydrocarbons (PAHs) from widely distributed Arctic marine sediments are interpreted to determine potential sources, examine their anthropogenic contribution and illuminate transport pathways. Results of principal components analysis reveal a distinction between natural and anthropogenic inputs and a direct linkage between anthropogenic emissions and Arctic contamination. An 'anthropogenic combustion' pattern for soils and sediments close to cities and industrial areas was observed, while different distributions are noted further away from industrial sites.

Published
1996

10. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic

Author

Feng, Xiaojuan, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., Van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montluçon, Daniel B., Eglinton, Timothy I., Earth and Climate, Organic geochemistry, and NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits

Subjects
terrestrial carbon markers, Global and Planetary Change, Atmospheric Science, Environmental Science(all), plant wax lipids, pan-arctic rivers, Environmental Chemistry, lignin, SDG 14 - Life Below Water, diacids, compound-specific radiocarbon analysis
Abstract

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.

Published
2015

13. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system

Author

Vonk, Jorien E., Giosan, Liviu, Blusztajn, Jerzy, Montlucon, Daniel, Graf Pannatier, Elisabeth, McIntyre, Cameron, Wacker, Lukas, Macdonald, Robie W., Yunker, Mark B., Eglinton, Timothy I., Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, and Earth and Climate

Subjects
Delta, Hydrology, Total organic carbon, δ18O, Sorting (sediment), Geochemistry, Sediment, Deposition (geology), Arctic, Geochemistry and Petrology, Sedimentary rock, SDG 14 - Life Below Water, Geology
Abstract

The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant representative of Arctic rivers. Here, we apply sedimentological (grain size, mineral surface area), and organic and inorganic geochemical techniques (%OC, δ13C-OC and δ14C-OC, 143Nd/144Nd, δ2H and δ18O, major and trace elements) on particulate, bank, channel and lake surface sediments from the Mackenzie Delta, as well as on surface sediments from the Mackenzie shelf in the Beaufort Sea. Our data show a hydrodynamic sorting effect resulting in the accumulation of finer-grained sediments in lake and shelf deposits. A general decrease in organic carbon (OC) to mineral surface area ratios from river-to-sea furthermore suggests a loss of mineral-bound terrestrial OC during transport through the delta and deposition on the shelf. The net isotopic value of the terrestrial OC that is lost en route, derived from relationships between δ13C, OC and surface area, is -28.5‰ for δ13C and -417‰ for δ14C. We calculated that OC burial efficiencies are around 55%, which are higher (~20%) than other large river systems such as the Amazon. Old sedimentary OC ages, up to 12 14C-ky, suggest the delivery of both a petrogenic OC source (with an estimated contribution of 19±9%) as well as a pre-aged terrestrial OC source. We calculated the 14C-age of this pre-aged, biogenic, component to be about 6100yrs, or -501‰, which illustrates that terrestrial OC in the watershed can reside for millennia in soils before being released into the river. Surface sediments in lakes across the delta (n=20) showed large variability in %OC (0.92-5.7%) and δ13C (-30.7‰ to -23.5‰). High-closure lakes, flooding only at exceptionally high water levels, hold high sedimentary OC contents (>2.5%) and young biogenic OC with a terrestrial or an autochthonous source whereas no-closure lakes, permanently connected to a river channel, hold sediments with pre-aged, terrestrial OC. The intermediate low-closure lakes, flooding every year during peak discharge, display the largest variability in OC content, age and source, likely reflecting variability in for example the length of river-lake connections, the distance to sediment source and the number of intermediate settling basins. Bank, channel and suspended sediment show variable 143Nd/144Nd values, yet there is a gradual but distinct spatial transition in 143Nd/144Nd (nearly three ε units; from -11.4 to -13.9) in the detrital fraction of lake surface sediments from the western to the eastern delta. This reflects the input of younger Peel River catchment material in the west and input of older geological source material in the east, and suggests that lake sediments can be used to assess variability in source watershed patterns across the delta.

Published
2015

14. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic : 14C characteristics of sedimentary carbon components and their environmental controls

Author

Feng, Xiaojuan, Gustafsson, Orjan, Holmes, Robert M., Vonk, Jorien E., van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montlucon, Daniel B., Eglinton, Timothy I., Feng, Xiaojuan, Gustafsson, Orjan, Holmes, Robert M., Vonk, Jorien E., van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montlucon, Daniel B., and Eglinton, Timothy I.

Abstract

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., 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., 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, 2016-05-02

Published
2016

15. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic : C-14 characteristics of sedimentary carbon components and their environmental controls

Author

Feng, Xiaojuan, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montlucon, Daniel B., Eglinton, Timothy I., Feng, Xiaojuan, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montlucon, Daniel B., and Eglinton, Timothy I.

Abstract

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 C-14 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 (C-24,C-26,C-28), plant wax FAs (C(24,26,2)8), and n-alkanes (C-27,C-29,C-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 (C-16,C-18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in C-14, 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 C-14 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.

Published
2015
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16. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: 14C characteristics of sedimentary carbon components and their environmental controls

Author

Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, Feng, Xiaojuan, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., Van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montluçon, Daniel B., Eglinton, Timothy I., Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, Feng, Xiaojuan, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., Van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montluçon, Daniel B., and Eglinton, Timothy I.

Published
2015

17. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system

Author

Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, Vonk, Jorien E., Giosan, Liviu, Blusztajn, Jerzy, Montlucon, Daniel, Graf Pannatier, Elisabeth, McIntyre, Cameron, Wacker, Lukas, Macdonald, Robie W., Yunker, Mark B., Eglinton, Timothy I., Organic geochemistry, NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits, Vonk, Jorien E., Giosan, Liviu, Blusztajn, Jerzy, Montlucon, Daniel, Graf Pannatier, Elisabeth, McIntyre, Cameron, Wacker, Lukas, Macdonald, Robie W., Yunker, Mark B., and Eglinton, Timothy I.

Published
2015

22. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: 14C characteristics of sedimentary carbon components and their environmental controls.

Author

Xiaojuan Feng, Gustafsson, Örjan, Holmes, R. Max, Vonk, Jorien E., van Dongen, Bart E., Semiletov, Igor P., Dudarev, Oleg V., Yunker, Mark B., Macdonald, Robie W., Wacker, Lukas, Montluçon, Daniel B., and Eglinton, Timothy I.

Subjects
CARBON isotopes, CUTIN, PLANT lipids, PERMAFROST, SUBERIN
Abstract

Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) poolsmobilized 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) weremuchmore 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 themobilization 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. [ABSTRACT FROM AUTHOR]

Published
2015
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