Does organic matter degradation affect the reconstruction of pre-industrial atmospheric mercury deposition rates from peat cores? — A test of the hypothesis using a permafrost peat deposit in northern Canada

Outridge, P.M.; Sanei, Hamed

doi:10.1016/j.coal.2010.04.004

Cited by 25 publications

(23 citation statements)

References 36 publications

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“…The 16 toppermafrost samples as well as permafrost cores represent contrasting soil types within the area downstream from the ice-dammed lake where the flooding and the associated erosion is considered most important for sediment transport in the Zackenberg River. Few studies have previously measured Hg concentrations in permafrost (Givelet et al, 2004;Outridge and Sanei, 2010). Those studies reported Hg concentrations in permafrost of peat sites ranging from~0.010 to 0.050 mg kg −1 , which is within the Hg concentration range measured in this study.…”

Section: Hg Concentrations In Soil Permafrost and Snow Within The Zamentioning

confidence: 52%

Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods

Søndergaard

Tamstorf

Elberling

et al. 2015

Science of The Total Environment

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Section: Hg Concentrations In Soil Permafrost and Snow Within The Zamentioning

confidence: 52%

Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods

Søndergaard

Tamstorf

Elberling

et al. 2015

Science of The Total Environment

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“…Significant correlation (r 2 = 0.41) was only found for an unidentified polysaccharide (Ps10, Supplement Table S1) and for 4-isopropenylphenol, the latter which is specific for Sphagnum. Higher values of HI (equivalent to high H / C) in peat deposits have been interpreted as hydrogen-rich labile C compounds in unprocessed OM (Outridge and Sanei, 2010). However, the HI index is thought to reflect aliphatic structures in general and the HI record of KK peat was positively correlated (r 2 = 0.49) with aliphatics determined by Py-GC-MS and with FTIR band 460 (aliphatics) (r 2 = 0.58) (not shown), but only weak (r 2 = 0.32 and 0.26) if correlated to the bands 2850 cm −1 and 2920 cm −1 , respectively (lipids, waxes, CH 2 stretching (2850 cm −1 ) (Supplement Table S3).…”

Section: Oxygen and Hydrogen Indices (Oi Hi)mentioning

confidence: 99%

“…Peat decomposition has also been intensively investigated by coal petrologists (Outridge and Sanei, 2010) often using Rock Eval © pyrolysis to determine H / C and O / C ratios (Carrie et al, 2012;Lafargue et al, 1998;Langford and Blanc-Valleron, 1990). This approach relies on the assumption that during decomposition of OM, labile compounds such as polysaccharides are preferentially decomposed while refractory aromatic or aliphatic compounds become residually enriched, causing a decrease of O / C and H / C ratios (Klavins et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Pyrolysis-GC-MS provides on the one hand molecular vegetation markers, which allow deciphering past changes in the bog's surface vegetation and, on the other hand, changes in the relative abundance of easily degradable and more resistant compounds that can be related to historical changes in peat decomposition linked to water table controlled redox conditions. Despite the fact that pyrolysis-GC-MS data are semi-quantitative, good agreement of peat pyrolysis data had been observed with C / N ratios , spectroscopic methods such as FTIR (González et al, 2003) and 13 C NMR (Buurman et al, 2006;Kaal et al, 2007;Pontevedra-Pombal et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of different methods to determine the degree of peat decomposition in peat bogs

et al. 2014

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Abstract. Peat humification or decomposition is a frequently used proxy to extract past time changes in hydrology and climate from peat bogs. During the past century several methods to determine changes in peat decomposition have been introduced. Most of these methods are operationally defined only and the chemical changes underlying the decomposition process are often poorly understood and lack validation. Owing to the chemically undefined nature of many humification analyses the comparison of results obtained by different methods is difficult. In this study we compared changes in peat decomposition proxies in cores of two peat bogs (Königsmoor, KK; Kleines Rotes Bruch, KRB) from the Harz Mountains (Germany) using C / N ratios, Fourier transform infrared spectra absorption (FTIR) intensities, Rock Eva® oxygen and hydrogen indices, δ13C and δ15N isotopic signatures and UV-absorption (UV-ABS) of NaOH peat extracts. In order to explain parallels and discrepancies between these methods, one of the cores was additionally analysed by pyrolysis gas chromatography mass spectrometry (pyrolysis-GC-MS). Pyrolysis-GC-MS data provide detailed information on a molecular level, which allows differentiation of both changes attributed to decomposition processes and changes in vegetation. Principal component analysis was used to identify and separate the effects of changes in vegetation pattern and decomposition processes because both may occur simultaneously upon changes in bog hydrology. Records of decomposition proxies show similar historical development at both sites, indicating external forcing such as climate as controlling the process. All decomposition proxies except UV-ABS and δ15N isotopes show similar patterns in their records and reflect to different extents signals of decomposition. The molecular composition of the KK core reveals that these changes are mainly attributed to decomposition processes and to a lesser extent to changes in vegetation. Changes in the molecular composition indicate that peat decomposition in the KK bog is mainly characterized by preferential decomposition of phenols and polysaccharides and relative enrichment of aliphatics during drier periods. Enrichment of lignin and other aromatics during decomposition was also observed but showed less variation than polysaccharides or aliphatics, and presumably reflects changes in vegetation associated with changes in hydrology of the bogs. Significant correlations with polysaccharide and aliphatic pyrolysis products were found for C / N ratios, FTIR-band intensities and for hydrogen index values, supporting that these decomposition indices provide reasonable information. Correlations of polysaccharide and aliphatic pyrolysis products with oxygen index values and δ13C was weaker, assumingly indicating carboxylation of the peat during drier periods and enrichment of isotopically lighter peat components during decomposition, respectively. FTIR, C / N ratio, pyrolysis-GC-MS analyses and Rock Eval hydrogen indices appear to reflect mass loss and related changes in the molecular peat composition during mineralization best. Pyrolysis-GC-MS allows disentangling the decomposition processes and vegetation changes. UV-ABS measurements of alkaline peat extracts show only weak correlation with other decomposition proxies and pyrolysis results as they mainly reflect the formation of humic acids through humification and to a lesser extent mass loss during mineralization.

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“…Organic matters strongly control mercury sequestration over geological time (Grasby et al 2013). Terrestrial mercury of atmospheric origin may potentially be transported to coastal sediments bound to organics or clay particles (Sanei and Goodarzi 2006;Outridge and Sanei 2010;Sanei et al 2010;Kongchum et al 2011;Sanei et al 2014). As a highly toxic element (Yudovich and Ketris 2005;Dai et al 2012b), mercury is a chemical of global concern owing to its long-range atmospheric transport and its persistence in the environment.…”

Section: Introductionmentioning

confidence: 99%

The distribution and occurrence of mercury in Chinese coals

Bai

Wang

et al. 2017

Int J Coal Sci Technol

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Mercury is one of the most concerned hazardous elements in coals. 1018 coal samples of different coal-forming periods, coal-accumulating areas and coal ranks all over the country were collected to study the distributions of mercury in Chinese coals. The modes of occurrence of mercury were studied with float-sink experiments of 10 coals from different basins in China and correlation analyses were conducted between concentrations of mercury and maceral and sulfur contents, as well as the ash yield. The theoretic concentrations and affinities of mercury in vitrinite, inertinite, clay and pyrite were then calculated following the methods proposed by Solari. The weighted average concentration of mercury in Chinese coals is 0.154 lg/g, which is similar to that in the word coals in general. The mercury concentrations vary largely in the coals of different coal-forming period and coal-accumulating areas as geological settings play key roles in determining the geochemistry of mercury. The concentrations of mercury in coals from south and southwest China and those from North China of C 3 -P 1 are relatively higher while those from North China of J 1-2 and Northeast of J 3 -K 1 relatively lower. The general distribution trends of mercury are very similar to that of ash yield, sulfur contents in coals. Pyrite is the dominant carrier of mercury in most coals, especially in some high-sulfur coals with abundant epigenetic pyrite formed during diagenesis and metamorphism. Mercury has higher affinity to vitrinite than to inertinite in most coals, which accords with the geological origin of macerals and geochemistry of mercury.

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Does organic matter degradation affect the reconstruction of pre-industrial atmospheric mercury deposition rates from peat cores? — A test of the hypothesis using a permafrost peat deposit in northern Canada

Cited by 25 publications

References 36 publications

Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods

Mercury exports from a High-Arctic river basin in Northeast Greenland (74°N) largely controlled by glacial lake outburst floods

Comparison of different methods to determine the degree of peat decomposition in peat bogs

The distribution and occurrence of mercury in Chinese coals

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