Reactivity of Triplet Excited States of Dissolved Natural Organic Matter in Stormflow from Mixed-Use Watersheds

McCabe, Andrew J.; Arnold, William A.

doi:10.1021/acs.est.7b01914

Cited by 60 publications

(106 citation statements)

References 72 publications

(216 reference statements)

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“…It is consistent with our hypothesis that

{AQY}_{normalT}^{normalc}

is positively related to relative open water land cover, assuming lignin polyphenols are photodegraded (with minor contribution from microbial degradation) during long surface water residence times (Benner and Kaiser ), thus lowering the rate of light absorption and increasing

{AQY}_{normalT}^{normalc}

. Photodegradation, however, cannot completely account for the positive relationship between

{AQY}_{normalT}^{normalc}

and open water land cover because 3 CDOM*‐precursors and CDOM are photodegraded at comparable rates, which translates to effectively no change in

{AQY}_{normalT}^{normalc}

(Sharpless et al ; McCabe and Arnold ). Logically, either moieties that inhibit 3 CDOM* formation must be preferentially removed and/or 3 CDOM*‐precursors must be preferentially formed.…”

Section: Resultssupporting

confidence: 85%

“…S6A, Section 6). Experimental results using samples from this study were combined with data from stormflow samples (McCabe and Arnold ) and prairie pothole wetland surface waters to formulate a simple linear model to estimate the IF TMP as a function of [DOC]:

\frac{1}{{IF}_{TMP}} = 0.028 (|, \pm 0.010) \cdot ([]|, DOC) + 1.01 (\pm 0.13),

…”

Section: Resultsmentioning

confidence: 99%

“…The rate constant,

k_{normalq}^{'}

, was estimated as 5.0(±2.5)×10 5 s −1 (Foote ; Canonica et al ), assuming the second order rate constant for the energy transfer from 3 CDOM* to O 2 is k q = 2(±1)×10 9 M −1 s −1 and the dissolved O 2 concentration in the reaction solutions was 2.4–2.8 × 10 −4 M at approximately 20°C and 101 kPa. The rate constant, k T,TMP , was estimated from experiments in which k obs,TMP was measured as a function of [TMP] 0 (5–750 μ M) in a subset of four samples selected to be representative of the range in wetland classes and watershed land covers (Al Housari et al ; Golanoski et al ; McCabe and Arnold ). To model these experiments, Eq.…”

Section: Methodsmentioning

confidence: 99%

“…McCabe and Arnold () showed that the inhibition factor of TMP photodegradation (IF TMP ) defined originally by Canonica and Laubscher () can be used to correct k obs,TMP for DOM‐induced inhibition according to Eq. .…”

Section: Methodsmentioning

confidence: 99%

“…High E2/E3 ratios are interpreted as high light absorption by discreet chromophores relative to CT complexes. Past work has suggested that AQY T is negatively correlated with DOM molecular weight (McKay et al ; Maizel and Remucal b ), however, DOM photodegradation and reduction of carbonyl moieties to hydroxyl moieties only modestly changes AQY T (Golanoski et al ; Sharpless et al ; McCabe and Arnold ). Despite our growing understanding of the photo‐physics of DOM light absorption and 3 CDOM* formation, models are lacking that specifically relate environmental variables, such as landscape condition and DOM source, to AQY T to allow large‐scale prediction of AQY T .…”

mentioning

confidence: 99%

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Multiple linear regression models to predict the formation efficiency of triplet excited states of dissolved organic matter in temperate wetlands

McCabe

Arnold

2018

Limnology & Oceanography

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The source and composition of dissolved organic matter (DOM) dictates light absorption in surface waters. Sunlight absorption by chromophoric dissolved organic matter (CDOM) forms reactive intermediates and drives global organic carbon processing. Triplet excited states of CDOM ( 3 CDOM*) are primary reactive intermediates formed by sunlight absorption by CDOM.3 CDOM* also produce secondary reactive intermediates, including radicals and reactive oxygen species, which are active in biogeochemical pathways. The efficiency of 3 CDOM* formation (apparent quantum yield, AQY T ) depends on DOM composition, especially DOM molecular weight. This dependence may arise from the greater probability of forming intra-molecular chargetransfer (CT) complexes in high-molecular weight DOM that inhibit 3 CDOM* formation. There are few examples that demonstrate this in field samples. In this report, vegetation, general hydrology, and watershed characteristics for 39 temperate wetlands, which are critical sources of high-molecular weight DOM, from the United States were defined and related to DOM composition and AQY T . The DOM bulk composition was assessed using absorbance and fluorescence spectroscopies. AQY T was estimated under simulated sunlight using the probe 2,4,6-trimethylphenol. Relatively high AQY T values (7%) were observed in wetlands with long hydroperiods and > 50% cropland watershed land cover compared to wetlands with >50% forest watershed land cover (< 1-4%). Low molecular weight DOM (E2/E3 > 7 and SUVA 254 < 3 L mg-C 21 m 21) and autochthonous DOM (b/a > 0.7) had relatively high AQY T estimates ($ 10%), indicating that allocthonous, high-molecular weight compounds produce 3 CDOM* less efficiently than autochthonous DOM. The CT theory of DOM light absorption and internal light-screening offer mechanistic explanations for these trends.Naturally occurring dissolved organic matter (DOM) is a complex mixture of components including aromatics from terrestrial plants and biomacromolecules from primary and secondary aquatic producers (Wilson 1987;Stenson et al. 2003;Nebbioso and Piccolo 2013). Wetlands are integral sources of DOM to the hydrosphere and function as natural reactors in DOM transformation (Watanabe et al. 2012;Raymond and Spencer 2015). The relative inputs of terrestrial and aquatic DOM, and thus DOM composition, changes from headwaters and isolated wetlands (terrene wetlands) to wetlands associated with lake basins and rivers (lentic and lotic wetlands, respectively) (M€ unster and Chr ost 1990;Larson et al. 2014;Yu et al. 2015). In headwater systems with surrounding shrubs, trees, or emergent vegetation, inputs of DOM are dominated by terrestrial sources, such as plant matter and soil organic matter (allochthonous DOM). In contrast, the composition of DOM in systems with large open water regions and long water residence times is dominated by exo-metabolites from photoautotrophs and pelagic heterotrophs as well as products of photo-and microbialdegradation (autochthonous DOM) (M€ unster and Chr ost ...

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“…It is consistent with our hypothesis that

{AQY}_{normalT}^{normalc}

{AQY}_{normalT}^{normalc}

. Photodegradation, however, cannot completely account for the positive relationship between

{AQY}_{normalT}^{normalc}

and open water land cover because 3 CDOM*‐precursors and CDOM are photodegraded at comparable rates, which translates to effectively no change in

{AQY}_{normalT}^{normalc}

(Sharpless et al ; McCabe and Arnold ). Logically, either moieties that inhibit 3 CDOM* formation must be preferentially removed and/or 3 CDOM*‐precursors must be preferentially formed.…”

Section: Resultssupporting

confidence: 85%

\frac{1}{{IF}_{TMP}} = 0.028 (|, \pm 0.010) \cdot ([]|, DOC) + 1.01 (\pm 0.13),

…”

Section: Resultsmentioning

confidence: 99%

“…The rate constant,

k_{normalq}^{'}

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Multiple linear regression models to predict the formation efficiency of triplet excited states of dissolved organic matter in temperate wetlands

McCabe

Arnold

2018

Limnology & Oceanography

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Study of the dissolved organic matter (DOM) of the Auzon cut-off meander (Allier River, France) by spectral and photoreactivity approaches

Palma

Sleiman

Voldoire

et al. 2020

Environ Sci Pollut Res

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Wetlands are recognized for the importance of their hydrological function and biodiversity, and there is now a consensus to protect and restore them as well as to complete the knowledge on their functioning. Here, we studied the dissolved organic matter (DOM) of a wetland composed of the Auzon cutoff meander, the Allier River, the alluvial fluvial flow, and watershed aquifer. Water was sampled at different locations, in spring, summer, and autumn. For each sample, DOM was characterized for its chemical and optical properties and its photooxidant capacity through its ability to generate DOM triplet excited states (3 DOM*) and singlet oxygen upon simulated solar light exposure. UV-visible and fluorescence indices revealed that DOM was mainly microbial-derived whatever the sampling sites with spatial and temporal variations in terms of aromaticity (5.5-22%), specific UV absorbance at 254 nm (0.28-2.82 L m −1 mgC −1), ratio of the absorbance at 254 and 365 nm (4.6-10.8), fluorescence index (1.35-166), and biological index (0.812-2.25). All the samples generated 3 DOM* and singlet oxygen, rates of formation of which showed parallel variations. Using principal component analysis (PCA), we found positive correlations between the sensitizing properties of DOM samples and parameters associated to the abundance of low molecular weight and low absorbing chromophores. Moreover, the parameter variation across the wetland reinforced the hydrological movements observed in a previous study, suggesting that these parameters could be used as water connection tracers.

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Effects of cyanobacterial accumulation and decomposition on the microenvironment in water and sediment

Zhang

Zhu

et al. 2020

J Soils Sediments

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Reactivity of Triplet Excited States of Dissolved Natural Organic Matter in Stormflow from Mixed-Use Watersheds

Cited by 60 publications

References 72 publications

Multiple linear regression models to predict the formation efficiency of triplet excited states of dissolved organic matter in temperate wetlands

Multiple linear regression models to predict the formation efficiency of triplet excited states of dissolved organic matter in temperate wetlands

Study of the dissolved organic matter (DOM) of the Auzon cut-off meander (Allier River, France) by spectral and photoreactivity approaches

Effects of cyanobacterial accumulation and decomposition on the microenvironment in water and sediment

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