Chemical characterization of dissolved organic material in Pony Lake, a saline coastal pond in Antarctica

Brown, Alexandra; McKnight, Diane M.; Chin, Yu‐Ping; Roberts, Edward; Uhle, Maria E.

doi:10.1016/j.marchem.2004.02.016

Cited by 87 publications

(111 citation statements)

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“…Ultrafiltration employing a tangential flow ultrafiltration system with a 1 kD nominal weight cutoff membrane was extensively evaluated by Ronald Benner and coworkers (e.g., Benner et al, 1992;Benner et al, 1997) and is widely used for the chemical characterization of DOM. Ultrafiltration may be followed by C 18 solid phase extraction (SPE) or XAD chromatography (Brown et al, 2004;Simjouw et al, 2005). It is important to realize that ultrafiltration is based on a physical separation of DOM, whereas SPE and XAD chromatography are based on chemical fractionation, which divide DOM into hydrophilic and hydrophobic compounds.…”

Section: Molecular Mass Distribution Of Dommentioning

confidence: 99%

“…A widely used method for the elucidation of the molecular mass distribution of DOM at a finer scale, which in addition provides information on the chemical composition of DOM, is size exclusion chromatography (SEC) and high-pressure size exclusion chromatography (HPSEC) (Brinkmann et al, 2003a;Brinkmann et al, 2003b;Brown et al, 2004;Chin et al, 1994;Gaberell et al, 2003;Reemtsma and These, 2005;Schmitt et al, 2001;Schwede-Thomas et al, 2005). SEC not only separates DOM compounds based on size (hydrodynamic radii), but also ion-exclusion and hydrophobic interactions of the fractions with the column material can occur (Schmitt et al, 2001).…”

Section: Molecular Mass Distribution Of Dommentioning

confidence: 99%

“…1). Some studies have used SEC or HPSEC followed by mass spectrometry (Reemtsma and These, 2005;Schmitt et al, 2001) or nuclear magnetic resonance (NMR) spectroscopy (Brown et al, 2004) (see also below).…”

Section: Molecular Mass Distribution Of Dommentioning

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: Molecular Mass Distribution Of Dommentioning

confidence: 99%

Section: Molecular Mass Distribution Of Dommentioning

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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“…Model humic compounds (Table 1) derived from a solely microbial source as well as terrestrial sources from both aquatic environments and soil systems exhibit many of the same optical properties despite their dispirit methods, of generation in the environment and source materials (Brown et al, 2004). All show a pH dependent absorbance, exhibit increasing absorbance as wavelength decreases and a loss of absorbance upon borohydride reduction (Ma et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…By removing a moiety suspected of participating in electronic interaction, long wavelength absorbance is partially or entirely lost and fluorescence emission increases and blue shifts (Ma et al, 2010). A direct comparison of divergent sources of fulvic and humic acid model compounds including an aquatic terrestrially derived fulvic acid, Suwannee River fulvic Acid (SRFA) and a microbial source of fulvic acid, Pony Lake fulvic Acid (PLFA) (Brown et al, 2004;McKnight et al, 1994), the soil derived humic acids Elliott humic acid (EHA) and Leonardite humic acid (LHA) and a terrestrially derived aquatic humic acid Suwannee River humic acid (SRHA) ( Table 1). Analysis and comparison of untreated and borohydride reduced model humic compounds particularly at short wavelength (< 350) using potentiometric and optical titrations, spectral slope values (S), difference plots (A) (Dryer et al, 2008), fluorescence emission spectra, (Jørgensen et al, 2011), and fluorescence difference spectra (F) (Del Vecchio & Blough, 2004) provide insight into how electronic interactions work universally in the environment as well as how differences that exist between sources humic materials can potentially augment existing knowledge about the fate and transport of humic substances in the environment (Hernes & Ronald Benner, 2002).…”

Section: Introductionmentioning

confidence: 99%

Probing the pH Dependent Optical Properties of Aquatic, Terrestrial and Microbial Humic Substances by Sodium Borohydride Reduction

Heighton¹,

Schmidt²

2014

JGG

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Chemically reducing humic (HA) and fulvic acids (FA) provides insight into spectroscopically identifiable structural moieties generating the optical properties of HA/FA from aquatic, microbial and terrestrial sources. Sodium borohydride reduction provides targeted reduction of carbonyl groups. The contrast between the pH induced optical changes of untreated, reduced and reoxidized HA/FA highlights differences in the quantity, and physicality of structural components generating optical properties associated with HA/FA. Because borohydride reactions alter pH, pH re-adjustment to the original pH is required. Careful titrations of selected HA/FA provided the mole H + g -1 HA/FA required to titrate reduced and reoxidized HA/FA from pH 2-11; and the pH dependent spectral slope (S) at low (pH 2-3), neutral (pH 7-7.5) and high (pH 11.0). Molar extinction coefficients () (Lmg -1 cm -1 ) at pH 7.6 and 350 nm provide a point of consistency linking intrinsic pH dependent optical properties to the concentration of material used for titrations. Soil derived humic acids differ from aquatic humic acids in the heterogeneity of optically identifiable group as well as the overall concentration of those groups. The microbial source of FA has a limited concentration of homogeneous titratable groups when compared to aquatic FA generated terrestrially. Microbial FA exhibits pH linked optical recovery upon reoxidation when compared to aquatic FA which is consistent with the presence of quinones in microbial FA.

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Interactions between sunlight and microorganisms influence dissolved organic matter degradation along the aquatic continuum

Cory

Kling

2018

Limnol Oceanogr Letters

179

141

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CO 2 emissions from inland surface waters to the atmosphere are almost as large as the net carbon transfer from the atmosphere to Earth's land surface. This large flux is supported by dissolved organic matter (DOM) from land and its complete oxidation to CO 2 in freshwaters. A critical nexus in the global carbon cycle is the fate of DOM, either complete or partial oxidation. Interactions between sunlight and microbes control DOM degradation, but the relative importance of photodegradation vs. degradation by microbes is poorly known. The knowledge gaps required to advance understanding of key interactions between photochemistry and biology influencing DOM degradation include: (1) the efficiencies and products of DOM photodegradation, (2) how do photo-products control microbial metabolism of photo-altered DOM and on what time scales, and (3) how do water and DOM residence times and light exposure interact to determine the fate of DOM moving across the landscape to oceans? Dissolved organic matter (DOM) dominates the pool sizes and fluxes in organic carbon and nutrient budgets in most aquatic ecosystems (Wetzel 2001). Because only 0.1% of net primary production on Earth is stored in aquatic sediments (Burdige 2007), tremendous amounts of particulate organic matter (POM) are degraded and pass through the *Correspondence: rmcory@umich.edu Author Contribution Statement: RMC and GWK led the manuscript effort and contributed equally to the literature synthesis, analysis of current evidence, and writing the manuscript.Data Availability Statement: Data used in this paper is archived at the Arctic Data Center https://arcticdata.io/catalog/#view/doi:10.18739/ A2SV8Z.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.This article is an invited paper to the Special Issue: Carbon cycling in inland waters Edited by: Emily Stanley and Paul del Giorgio Scientific Significance Statement CO 2 emissions from inland surface waters to the atmosphere are almost as large as the net carbon transfer from the atmosphere to Earth's land surface. This large flux is supported by the movement of dissolved organic matter (DOM) from land and its subsequent oxidation to CO 2 in freshwaters as a result of interactions between sunlight and microbes. These interactions are poorly known, but measuring the coupled "photo-bio" degradation of DOM is critical to understanding DOM fate. Changes in inland waters from climate or land-use are affecting the fundamental controls on the processing of DOM by sunlight. Thus, this literature synthesis highlights the approaches and knowledge needed to understand the role of sunlight in DOM processing within aquatic ecosystems and across ecosystems at landscape scales. DOM pool on different time scales. POM to DOM conversion and DOM processing can be rapid; e.g., Meyers et al. (1984) found > 90% of the photosynthetically formed POM was mineralized annually with...

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Chemical characterization of dissolved organic material in Pony Lake, a saline coastal pond in Antarctica

Cited by 87 publications

References 17 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

Probing the pH Dependent Optical Properties of Aquatic, Terrestrial and Microbial Humic Substances by Sodium Borohydride Reduction

Interactions between sunlight and microorganisms influence dissolved organic matter degradation along the aquatic continuum

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