Source and biolability of ancient dissolved organic matter in glacier and lake ecosystems on the Tibetan Plateau

Spencer, Robert G. M.; Guo, Weidong; Raymond, Peter A.; Dittmar, Thorsten; Hood, Eran; Fellman, Jason B.; Stubbins, Aron

doi:10.1016/j.gca.2014.08.006

Cited by 208 publications

(254 citation statements)

References 59 publications

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“…Hydrophobic acid isolates from reverse osmosis of SR NOM II collected in 2012 have a higher average molecular weight, and 13 C NMR studies revealed more aromatic functional groups than for SR NOM I (Kreller et al, 2015;Nwosu and Cook, 2014). This suggests that this site may have been influenced by aerosol anthropogenic input (Stubbins et al, 2012b;Spencer et al, 2014).…”

Section: Spe-doc and Bc Cyclingmentioning

confidence: 99%

Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

2015

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a b s t r a c t a r t i c l e i n f oRadiocarbon analysis is a powerful tool for understanding the cycling of individual components within carbon pools, such as black carbon (BC) in dissolved organic carbon (DOC). Radiocarbon (Δ 14 C) measurements of BC in DOC provide insight into one source of aged, recalcitrant DOC. We report a modified solid phase extraction (SPE) method to concentrate 43 ± 6% of DOC (SPE-DOC) from seawater. We used the Benzene Polycarboxylic Acid (BPCA) method to isolate BC from SPE-DOC (SPE-BC) for subsequent 14 C analysis. We report SPE-BC Δ 14 C values, SPE-BC concentrations, and the relative BPCA distributions from Milli-Q water process blanks, two riverine reference standards, as well as a coastal and an open ocean surface water sample. The composition of BC is less aromatic in the ocean samples than those in the river standards. We find higher BC Δ 14 C values in the river standards (+148 to −462‰) than BC in the ocean samples (−592 to −712‰), suggesting that BC ages within oceanic DOC. We report that BC is 4.2 ± 1.0% of SPE-DOC in the open ocean surface sample, or 1.4 ± 0.1 μM C. This work provides the methodological basis by which global BC concentrations, compositions (e.g. relative abundances of BPCA marker compounds) and Δ 14C values can be assessed.

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Section: Spe-doc and Bc Cyclingmentioning

confidence: 99%

Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

2015

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“…In addition, photochemical reaction and photolysis of WSOC (Grannas et al, 2004), air-snow exchange processes, leaching processes, or washout by the snow meltwater, or WSOC in surface snow was re-emitted in the atmosphere when snow is aging, all of those factors might result in the decreasing trend of WSOC concentrations in surface aged snow on glaciers during the entire monsoon season. Moreover, since a large portion of glacier-derived WSOC has proven to be highly bioavailable (Hood et al, 2009;Singer et al, 2012;Legrand et al, 2013a;Spencer et al, 2014), WSOC content was exponentially decreased during the period of in situ observations (biodegradation experiment) (Yan et al, 2016). To clarify the physico-chemical processes and leaching effect of the WSOC concentrations in snow pits, we analyzed the vertical distribution of WSOC concentrations.…”

Section: Depletion and Leaching Of Wsoc In The Snowpackmentioning

confidence: 99%

“…However, the relevant dataset on WSOC is sparse in the TP (Spencer et al, 2014;Yan et al, 2015;Li et al, 2016a, b;Niu et al, 2017b) because of the harsh environmental and logistical difficulties. The TP, also called 'the Third Pole' of the world (Xu et al, 2009;Yao et al, 2012a), is one of the most remote and isolated regions in the world, and holds the largest quantity of glaciers at middle latitudes (Li et al, 2016a).…”

Section: Introductionmentioning

confidence: 99%

Distributions and light absorption property of water soluble organic carbon in a typical temperate glacier, southeastern Tibetan Plateau

Niu

Kang

et al. 2018

Tellus B: Chemical and Physical Meteorology

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“…Ratios are then used to determine the elemental composition of compounds present. This technique has been applied to natural organic matter in a variety of environments (Chipman et al, 2010;Kim et al, 2006;Spencer et al, 2014;Tfaily et al, 2013), including DOC in groundwater (Evert, 2015;Longnecker 15 and Kujawinski, 2011). But no studies that we could find have assessed the molecular composition of OC associated with aquifer sediment (i.e., SOC).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of organic matter mobilized from Bangladeshi aquifer sediment: tracking carbon compositional change during microbial utilization

Pracht¹,

Tfaily²,

Ardissono³

et al. 2017

Preprint

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Abstract. Bioavailable organic carbon in aquifer-recharge waters and sediments can fuel microbial reactions with 10 implications for groundwater quality. A previous incubation experiment showed that sedimentary organic carbon (SOC) mobilized off sandy sediment collected from an arsenic-contaminated and methanogenic aquifer in Bangladesh was bioavailable; it was fermented into methane. We used high-resolution mass spectrometry to molecularly characterize this mobilized SOC, reference its composition against dissolved organic carbon (DOC) in aquifer recharge water, track compositional changes during incubation, and advance understanding of how composition relates to bioavailability in 15 anaerobic conditions. Mobilized SOC was more diverse and proportionately larger, more aromatic and more oxidized than DOC in surface recharge. In all samples, ~50% of identified compounds contained sulfur. After SOC was fermented into methane, new organosulfur compounds with high S-to-C ratios and high nominal oxidation state of carbon (NOSC) were detected. We conjecture these detected compounds were microbially synthesized to biochemically support methane production or they formed abiotically following microbial sulfate reduction, which could have occurred during incubation 20 but was not directly measured. Microbes transformed all carbon types during incubation, including those considered molecularly recalcitrant (e.g., condensed aromatics) and thermodynamically unfavourable to oxidize (e.g., low NOSC).While all compound types were eventually degraded, NOSC and compound size controlled the rates of carbon transformation. Large energy-rich compounds (e.g., aromatics with high NOSC) were targeted first while small energy-poor compounds (e.g., alkanes and olefinics with low NOSC) persisted. Preferential use of aromatic compounds, which are 25 typically considered molecularly recalcitrant, demonstrates that in the anaerobic conditions of the incubation, thermodynamic favourability of carbon oxidation rather than molecular structure controlled the rate of carbon degradation by microbes.Biogeosciences Discuss., https://doi

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Source and biolability of ancient dissolved organic matter in glacier and lake ecosystems on the Tibetan Plateau

Cited by 208 publications

References 59 publications

Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

Distributions and light absorption property of water soluble organic carbon in a typical temperate glacier, southeastern Tibetan Plateau

Molecular characterization of organic matter mobilized from Bangladeshi aquifer sediment: tracking carbon compositional change during microbial utilization

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