Production and Composition of Pyrogenic Dissolved Organic Matter From a Logical Series of Laboratory-Generated Chars

Bostick, Kyle W.; Zimmerman, Andrew R.; Wozniak, Andrew S.; Mitra, Siddhartha; Hatcher, Patrick G.

doi:10.3389/feart.2018.00043

Cited by 69 publications

(141 citation statements)

References 68 publications

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“…What is most interesting is the fact that char is more concentrated in humic acids than in humin for both peat samples. Normally biochar is very insoluble in aqueous solvents (Bostick et al, 2018) and would be expected to remain in the humin fraction, contrary to what is observed here. The fact that char became soluble on treatment with dilute alkali and populated the humic acid fraction suggests that this char evolved from secondary synthesis.…”

Section: Resultscontrasting

confidence: 94%

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR

2019

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Humic extracts, in particular humic acids, of organic-rich peat soils were examined by solid-state 13 C nuclear magnetic resonance (NMR) and shown to be integral components of the peat, contrary to recent suggestions that humic materials are artifacts of alkali extraction. The authenticity of humic substances is demonstrated by recombining the various humic fractions and comparing the NMR spectrum of the recombined peat with the original untreated peat sample. Even though significant NMR-determined structural differences exist between humic acids and the insoluble humin fractions, the recombination reproduces the original unextracted peat quite well. Applying a biopolymer mixing model to the spectra shows that humic acids have a high proportion of char-like material that is interpreted as being derived from noncombustion polymerization or secondary synthesis during humification, a process that has been challenged by a recent soil formation model.

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Section: Resultscontrasting

confidence: 94%

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR

2019

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“…However, the use of BPCA ratios to accurately constrain sources of DBC in dynamic fluvial systems is not straightforward. Environmental processes, such as photodegradation of DOM (Stubbins & Dittmar, 2012; Wagner & Jaffé, 2015), photodissolution of suspended sediments (Roebuck et al, 2018), and sorption‐desorption (Bostick et al, 2018; Wagner, Ding, & Jaffé, 2017), can alter or homogenize BPCA signatures, thereby erasing any perceptible link between BPCA ratio and DBC source. To overcome the limitations associated with BPCA ratios, we also used compound‐specific δ 13 C signatures to discern potential sources of DBC in the Congo River.…”

Section: Resultsmentioning

confidence: 99%

Du Feu à l'Eau: Source and Flux of Dissolved Black Carbon From the Congo River

Drake

Wagner

Stubbins

et al. 2020

Global Biogeochemical Cycles

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Pyrogenic organic residues from wildfires and anthropogenic combustion are ubiquitous in the environment and susceptible to leaching from soils into rivers, where they are known as dissolved black carbon (DBC). Here we quantified and isotopically characterized DBC from the second largest river on Earth, the Congo, using 12 samples collected across three annual hydrographs from 2010 to 2012. We find that the Congo River exports an average of 803 ± 84 Gg‐C as DBC per year, comprising 7.5% of the river's average annual dissolved organic carbon (DOC) flux (10.7 ± 1.2 Tg‐C yr−1). Concentrations of DBC were strongly correlated with discharge and DOC concentration, indicating transport limitation for DBC flux from the Congo River Basin. Stable carbon isotopic signatures of DBC revealed a seasonal shift in pyrogenic source from forest dominant to an increasing contribution from savannah biomass, which derives from the North‐South bimodal hydrologic regime within the basin. Our results also indicate that black carbon produced within the Congo Basin is exported by the river on relatively short time scales and that total DBC export will increase with climate change predictions for the central African region.

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“…The increases in DOC concentration in treatment flumes can be explained by leaching of pyrogenic organic matter from wildfire charcoals, as also observed in previous laboratory studies. 43,44 Our results indicate that DOC-leaching from PyC exceeds the adsorption of riverine DOC to PyC under conditions such as the ones studied here. The amount of DOC released from filter bags in the field experiments was estimated as:…”

Section: Discussionmentioning

confidence: 52%

Wildfire-Derived Pyrogenic Carbon Modulates Organic Matter and Microbial Functioning in a Fluvial Ecosystem

Bistarelli¹,

Poyntner²,

Santín³

et al. 2021

Preprint

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Wildfires produce large amounts of pyrogenic carbon (PyC), including particulate charcoal, known for its chemical recalcitrance and sorption affinity for organic molecules. Wildfire-derived PyC is highly mobile in the landscape and can be transported to fluvial networks where it may impact natural dissolved organic matter (DOM) and microbial biofilms. The effects of PyC on freshwater ecosystems and carbon cycling therein remain poorly investigated. To address this research gap, we used in-stream flumes with a control vs treatment design (pulse addition of PyC particles). We present evidence that field-aged PyC inputs into river ecosystems can alter dissolved organic carbon (DOC) concentration, DOM composition, pH, and enzymatic activities in benthic biofilms. In stream DOM composition was altered due to leaching of pyrogenic DOM from PyC and possible concurrent sorption of riverine DOM to PyC. DOM changes and increase in pH were associated with changes in enzymatic activities, which reflected preferential usageof recalcitrant over easily available DOM by biofilms. Furthermore, we observed particulate PyC sedimentation on biofilm surfaces, which may further modulate the impacts of PyC. This study highlights the importance of PyC for in-stream DOM propertiesand biofilm functioning with implications for in-stream biogeochemical cycling in fire affected watersheds. <br>

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Production and Composition of Pyrogenic Dissolved Organic Matter From a Logical Series of Laboratory-Generated Chars

Cited by 69 publications

References 68 publications

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR

Du Feu à l'Eau: Source and Flux of Dissolved Black Carbon From the Congo River

Wildfire-Derived Pyrogenic Carbon Modulates Organic Matter and Microbial Functioning in a Fluvial Ecosystem

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Production and Composition of Pyrogenic Dissolved Organic Matter From a Logical Series of Laboratory-Generated Chars

Cited by 69 publications

References 68 publications

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State 13C NMR

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State 13C NMR

Du Feu à l'Eau: Source and Flux of Dissolved Black Carbon From the Congo River

Wildfire-Derived Pyrogenic Carbon Modulates Organic Matter and Microbial Functioning in a Fluvial Ecosystem

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Product

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Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR

Evidence for the Existence of Humic Acids in Peat Soils Based on Solid‐State ¹³C NMR