The importance of aromaticity to describe the interactions of organic matter with carbonaceous materials depends on molecular weight and sorbent geometry

Castan, Stephanie; Sigmund, Gabriel; Hüffer, Thorsten; Tepe, Nathalie; Kammer, Frank von der; Chefetz, Benny; Hofmann, Thilo

doi:10.1039/d0em00267d

“…In addition to pyrogenic DOM, PyC particles can also affect DOM composition and its bioaccessibility by interacting with riverine DOM via selective adsorption. This process has previously been observed for other carbonaceous materials, including carbon nanomaterials, 25 , 26 graphite, and biochar. 26 …”

Section: Introductionsupporting

confidence: 73%

Wildfire-Derived Pyrogenic Carbon Modulates Riverine Organic Matter and Biofilm Enzyme Activities in an In Situ Flume Experiment

Bistarelli

¹

,

Poyntner

²

,

Santín

³

et al. 2021

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Wildfires produce large amounts of pyrogenic carbon (PyC), including charcoal, known for its chemical recalcitrance and sorption affinity for organic molecules. Wildfire-derived PyC can be transported to fluvial networks. Here it may alter the dissolved organic matter (DOM) concentration and composition as well as microbial biofilm functioning. Effects of PyC on carbon cycling in freshwater ecosystems remain poorly investigated. Employing in-stream flumes with a control versus treatment design (PyC pulse addition), we present evidence that field-aged PyC inputs to rivers can increase the dissolved organic carbon (DOC) concentration and alter the DOM composition. DOM fluorescence components were not affected by PyC. The in-stream DOM composition was altered due to leaching of pyrogenic DOM from PyC and possibly concurrent sorption of riverine DOM to PyC. Decreased DOM aromaticity indicated by a lower SUVA 245 (−0.31 unit) and a higher pH (0.25 unit) was associated with changes in enzymatic activities in benthic biofilms, including a lower recalcitrance index (β-glucosidase/phenol oxidase), suggesting preferential usage of recalcitrant over readily available DOM by biofilms. The deposition of particulate PyC onto biofilms may further modulate the impacts of PyC due to direct contact with the biofilm matrix. This study highlights the importance of PyC for in-stream biogeochemical organic matter cycling in fire-affected watersheds.

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“…9,16,17 PyC particles can interact with the riverine DOM via selective adsorption, thus affecting DOM composition and susceptibility to microbial metabolism. This process has previously been observed for other carbonaceous materials, including carbon-nanomaterials, 18,19 graphite, and biochar. 19 PyC can also disintegrate into smaller particles, and leach organic matter as well as metals.…”

Section: Introductionsupporting

confidence: 73%

“…This process has previously been observed for other carbonaceous materials, including carbon-nanomaterials, 18,19 graphite, and biochar. 19 PyC can also disintegrate into smaller particles, and leach organic matter as well as metals. [20][21][22] Here we report on a field experiment in a natural river to investigate the effects of wildfirederived PyC inputs on in-stream DOM properties and biofilm functioning.…”

Section: Introductionsupporting

confidence: 73%

“…The SUVA254 measurements are in line with recent studies showing that sorption of DOM to PyC particles increases with DOM aromaticity and can be hindered by steric effects excluding very large DOM molecules from reaching certain sorption sites within the charcoal particles. 19,45 PARAFAC, a modelling approach used to unravel chemical signatures from EEMs, resulted in the detection of 4 components (see Fig. 4 and OpenFluor PARAFAC report (https://openfluor.lablicate.com/of/measurement/2604)).…”

Section: Pyrogenic Carbon Addition Changes Dom Compositionmentioning

confidence: 99%

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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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0

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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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“…3) could additionally suggest that selective sorption of riverine DOM by PyC simultaneously aromaticity and can be hindered by steric effects excluding very large DOM molecules from reaching certain sorption sites within the charcoal particles. 19,45 PARAFAC, a modelling approach used to unravel chemical signatures from EEMs, resulted in the detection of 4 components (see Fig. 4 and OpenFluor PARAFAC report (https://openfluor.lablicate.com/of/measurement/2604)).…”

Section: Pyrogenic Carbon Addition Changes Dom Compositionmentioning

confidence: 99%

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

L¹,

Poyntner²,

Santín³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

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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The importance of aromaticity to describe the interactions of organic matter with carbonaceous materials depends on molecular weight and sorbent geometry

Abstract: DOM sorption by CMs is generally controlled by DOM aromaticity but complex sorbent surfaces with high porosity, curvatures and functional groups strongly reduce the importance of aromaticity for sorption.

Cited by 18 publications

References 49 publications

Wildfire-Derived Pyrogenic Carbon Modulates Riverine Organic Matter and Biofilm Enzyme Activities in an In Situ Flume Experiment

Wildfire-Derived Pyrogenic Carbon Modulates Riverine Organic Matter and Biofilm Enzyme Activities in an In Situ Flume Experiment

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

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

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