Chemical characterization of DOM in channels of a seasonal wetland

Mladenov, Natalie; McKnight, Diane M.; Macko, S.; Norris, Marnie J; Cory, Rose M.; Ramberg, Lars

doi:10.1007/s00027-007-0905-2

Cited by 55 publications

(40 citation statements)

References 56 publications

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“…Among non-invasive techniques, nuclear magnetic resonance (NMR) spectroscopy, particularly solid-state 13 C NMR is frequently used for the identification of the bulk chemical composition of DOM (Baldock et al, 2004;Benner et al, 1992;Brown et al, 2004;Chin et al, 1994;Clair and Sayer, 1997;Cory and McKnight, 2005;Dria et al, 2002;Fan et al, 2000;Fimmen et al, 2007;Gaberell et al, 2003;Hedges et al, 1992;Hertkorn et al, 2006;Kaiser et al, 2003;Maie et al, 2005;McKnight et al, 2003;Mladenov et al, 2007;Novotny et al, 2007;Rodriguez-Zuniga et al, 2008;Schwede-Thomas et al, 2005;Wetzel et al, 1995).…”

Section: Bulk Characterization Of Dommentioning

confidence: 99%

“…The specific UV-absorbance of CDOM (SUVA), which is defined as the UV absorbance of a water sample at a given wavelength in the UV region (usually at 280 nm), normalized to DOC concentration, has been shown to correlate with the fraction of aromatic compounds contained in CDOM (Chin et al, 1994;Gaberell et al, 2003;Hassellçv, 2005;Mladenov et al, 2007;Weishaar et al, 2003).…”

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confidence: 99%

“…In addition to UV/VIS absorption spectroscopy, fluorescence spectroscopy has been used to delineate the chemical composition and origin of CDOM, particularly three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy (Boehme et al, 2004;Boyd and Osburn, 2004;Coble et al, 1990;Conmy et al, 2004;Cory and McKnight, 2005;Fulton et al, 2004;Jiang et al, 2008;Kowalczuk et al, 2003;Kowalczuk et al, 2005;McKnight et al, 2001;Mladenov et al, 2007;Murphy et al, 2008;Stedmon and Markager, 2005a;Stedmon and Markager, 2005b;Vähätalo and Wetzel, 2008;Zepp et al, 2004). The combination of EEM with parallel factor data analysis allows the chemical identification of fluorophores, e.g., quinone-like fluorophores (Cory and McKnight, 2005;Mladenov et al, 2007;Stedmon and Markager, 2005a;Stedmon and Markager, 2005b).…”

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confidence: 99%

“…The combination of EEM with parallel factor data analysis allows the chemical identification of fluorophores, e.g., quinone-like fluorophores (Cory and McKnight, 2005;Mladenov et al, 2007;Stedmon and Markager, 2005a;Stedmon and Markager, 2005b). EEM also provides information on the redox properties of DOM (Cory and McKnight, 2005).…”

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confidence: 99%

“…The fluorescence index (FI), which is the ratio of emission intensity (450 nm / 500 nm) at 370 nm excitation (McKnight et al, 2001), is correlated to the relative contribution of autochthonous versus terrigenous DOM, and therefore a valuable tool for DOM source identification (Battin, 1998;Boyd and Osburn, 2004;Cory and McKnight, 2005;Fimmen et al, 2007;McKnight et al, 2001;Mladenov et al, 2007;Schwede-Thomas et al, 2005). For example, McKnight and coworkers (2001) found a value of~1…”

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confidence: 99%

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Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability

2009

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Abstract. UV-induced transformations of colored dissolved organic matter (CDOM, which is part of dissolved organic matter, DOM) affect CDOM absorption properties resulting in the loss of color (referred to as photobleaching). CDOM photobleaching increases the penetration depths of the damaging UV-B radiation into water bodies and strongly depends on the wavelength of solar radiation and on the pH of aquatic systems. UV-induced transformations also affect DOM availability to bacterioplankton, often enhancing the bioavailability of terrigenous DOM and in turn microbial respiration. The combination of UV-induced enhancement of DOM bioavailability and increased export of terrigeneous DOM into estuaries and coastal waters due to climaterelated changes in continental hydrology could result in a UV-mediated positive feedback of CO 2 accumulation in the atmosphere.The extent and type of CDOM photobleaching and of UV-induced changes in DOM bioavailability depend on (C)DOM chemical composition, which in turn undergoes drastic changes upon UV-induced transformations. Therefore, the chemical characterization of (C)DOM is key for rationalizing UV-induced transformations. In the second section (after the "Introduction"), we review important methods for the elucidation of the chemical composition of (C)DOM. However, this article is not intended to be comprehensive regarding (C)DOM chemical characterization. An important purpose is to provide photochemical bases for the understanding of UV-induced changes of (C)DOM absorption properties and bioavailability (mainly discussed in the sections "Pathways of DOM phototransformations" and "UV-induced changes of the absorption properties of CDOM").

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Section: Bulk Characterization Of Dommentioning

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Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability

2009

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Variations in high‐latitude riverine fluorescent dissolved organic matter: A comparison of large Arctic rivers

2013

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[1] Given the pace of climate change, it is important to better understand dissolved organic matter (DOM) storage and cycling in high-latitude rivers and its subsequent export to the Arctic Ocean. To address this concern, excitation/emission matrix spectroscopy and parallel factor analysis (PARAFAC) coupled with optical indices were used to characterize the optical properties of fluorescent DOM (FDOM) and colored DOM (CDOM) in five large Arctic rivers over two seasonal cycles. Five PARAFAC components were identified and proved useful indicators for the quantitative and qualitative descriptions of DOM sources and modification processes within Arctic watersheds. In comparing Pan-Arctic relationships between the optical properties and chemical properties of DOM, three components traced terrigenous biomarkers and two components are introduced as potential indicators for microbial processing. Conversely, no individual PARAFAC component could be directly linked to a specific plant source or river and simpler absorbance indices (i.e., a 350 ) proved to be better suited to quantify dissolved organic carbon and lignin phenol concentrations. Differences in FDOM character between the rivers could be explained by general watershed characteristics, including vegetation, topography, and hydrology. Based on these differences, the influence of coniferous vegetation on DOM character is most apparent in the Lena and Yenisei Rivers and bog-derived FDOM sources are more important in the Ob River. This study illustrates how increased hydrological connectivity in the Ob catchment and the abundance of lakes within the Mackenzie watershed may influence FDOM concentrations and the microbial processing of DOM within these watersheds.

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The biogeochemistry of carbon across a gradient of streams and rivers within the Congo Basin

Mann

Spencer

Dinga³

et al. 2014

J. Geophys. Res. Biogeosci.

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Dissolved organic carbon (DOC) and inorganic carbon (DIC, pCO 2 ), lignin biomarkers, and theoptical properties of dissolved organic matter (DOM) were measured in a gradient of streams and rivers within the Congo Basin, with the aim of examining how vegetation cover and hydrology influences the composition and concentration of fluvial carbon (C). Three sampling campaigns (February 2010, November 2010, and August 2011 spanning 56 sites are compared by subbasin watershed land cover type (savannah, tropical forest, and swamp) and hydrologic regime (high, intermediate, and low). Land cover properties predominately controlled the amount and quality of DOC, chromophoric DOM (CDOM) and lignin phenol concentrations (∑ 8 ) exported in streams and rivers throughout the Congo Basin. Higher DIC concentrations and changing DOM composition (lower molecular weight, less aromatic C) during periods of low hydrologic flow indicated shifting rapid overland supply pathways in wet conditions to deeper groundwater inputs during drier periods. Lower DOC concentrations in forest and swamp subbasins were apparent with increasing catchment area, indicating enhanced DOC loss with extended water residence time. Surface water pCO 2 in savannah and tropical forest catchments ranged between 2,600 and 11,922 μatm, with swamp regions exhibiting extremely high pCO 2 (10,598-15,802 μatm), highlighting their potential as significant pathways for water-air efflux. Our data suggest that the quantity and quality of DOM exported to streams and rivers are largely driven by terrestrial ecosystem structure and that anthropogenic land use or climate change may impact fluvial C composition and reactivity, with ramifications for regional C budgets and future climate scenarios.

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Chemical characterization of DOM in channels of a seasonal wetland

Cited by 55 publications

References 56 publications

Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability

Chemical characterization of dissolved organic matter (DOM): A prerequisite for understanding UV-induced changes of DOM absorption properties and bioavailability

Variations in high‐latitude riverine fluorescent dissolved organic matter: A comparison of large Arctic rivers

The biogeochemistry of carbon across a gradient of streams and rivers within the Congo Basin

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