scholarly journals Spatial and diurnal dynamics of dissolved organic matter (DOM) fluorescence and H 2 O 2 and the photochemical oxygen demand of surface water DOM across the subtropical Atlantic Ocean

2001 ◽  
Vol 46 (3) ◽  
pp. 632-643 ◽  
Author(s):  
Ingrid Obernosterer, ◽  
Piet Ruardij ◽  
Gerhard J. Herndl
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Atlantic Ocean ◽  
Dissolved Organic Matter ◽  
Oxygen Demand ◽  
Diurnal Dynamics

scholarly journals Optimization of coagulation-flocculation process in the treatment of surface water for a maximum dissolved organic matter removal using RSM approach

2021 ◽  
Author(s):  
Sami Khettaf ◽  
Imen Khounı ◽  
Ghofrane Louhichi ◽  
Ahmed Ghrabi ◽  
Latifa Bousselmi ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Research Work ◽  
Oxygen Demand ◽  
Optimal Conditions ◽  
Jar Test ◽  
Initial Ph ◽  
Flocculation Process

Abstract The aim of this research work is the optimization of the coagulation/flocculation process in the treatment of surface water for a maximum dissolved organic matter (DOM) removal using response surface methodology (RSM). For this purpose, several jar test experiments have been performed in order to identify the most influencing factors. Afterwards, RSM has been done to investigate the effects and the interactions of three chosen variables (coagulant concentration, flocculent concentration, and initial pH), whereas the responses were the DOM removal in terms of chemical oxygen demand (COD), in terms of absorbance at the wavelength 254 nm (UV-254), and the final pH. The optimal conditions were as follows: 133 mg/L of coagulant, 60 mg/L of flocculent and an initial pH equal to 6.91. Under these conditions, the efficiency removals were 56% in terms of COD and 59% in terms of UV-254 with a final pH equal to 6.78. High variance coefficient R2 values, with 0.96 for the removal in terms of COD and 0.92 in terms of UV-254 confirm the reliability and the validity of the obtained model.

Removal of the Neutral Dissolved Organic Matter (NDOM) from Surface Water by Coagulation/Flocculation and Nanofiltration

2021 ◽  
pp. 1-14
Author(s):  
Sami Khettaf ◽  
Roumaissa Boumaraf ◽  
Fatiha Benmahdi ◽  
Kamel-Eddine Bouhidel ◽  
Mohammed Bouhelassa
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter

scholarly journals Particulate and Dissolved Organic Matter in Stormwater Runoff Influences Oxygen Demand in Urbanized Headwater Catchments

2021 ◽  
Author(s):  
Kelly M. McCabe ◽  
Erik M. Smith ◽  
Susan Q. Lang ◽  
Christopher L. Osburn ◽  
Claudia R. Benitez-Nelson
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Stormwater Runoff ◽  
Oxygen Demand ◽  
Headwater Catchments

scholarly journals Photomineralization and photomethanification of dissolved organic matter in Saguenay River surface water

2015 ◽  
Vol 12 (22) ◽  
pp. 6823-6836 ◽  
Author(s):  
Y. Zhang ◽  
H. Xie
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Dimethyl Sulfide ◽  
Ultraviolet B ◽  
Global Ocean ◽  
Quantum Yields ◽  
Methyl Radical ◽  
Ch4 Production ◽  
Saguenay River

Abstract. Rates and apparent quantum yields of photomineralization (AQYDOC) and photomethanification (AQYCH4) of chromophoric dissolved organic matter (CDOM) in Saguenay River surface water were determined at three widely differing dissolved oxygen concentrations ([O2]) (suboxic, air saturation, and oxygenated) using simulated-solar radiation. Photomineralization increased linearly with CDOM absorbance photobleaching for all three O2 treatments. Whereas the rate of photochemical dissolved organic carbon (DOC) loss increased with increasing [O2], the ratio of fractional DOC loss to fractional absorbance loss showed an inverse trend. CDOM photodegradation led to a higher degree of mineralization under suboxic conditions than under oxic conditions. AQYDOC determined under oxygenated, suboxic, and air-saturated conditions increased, decreased, and remained largely constant with photobleaching, respectively; AQYDOC obtained under air saturation with short-term irradiations could thus be applied to longer exposures. AQYDOC decreased successively from ultraviolet B (UVB) to ultraviolet A (UVA) to visible (VIS), which, alongside the solar irradiance spectrum, points to VIS and UVA being the primary drivers for photomineralization in the water column. The photomineralization rate in the Saguenay River was estimated to be 2.31 × 108 mol C yr−1, accounting for only 1 % of the annual DOC input into this system. Photoproduction of CH4 occurred under both suboxic and oxic conditions and increased with decreasing [O2], with the rate under suboxic conditions ~ 7–8 times that under oxic conditions. Photoproduction of CH4 under oxic conditions increased linearly with photomineralization and photobleaching. Under air saturation, 0.00057 % of the photochemical DOC loss was diverted to CH4, giving a photochemical CH4 production rate of 4.36 × 10−6 mol m−2 yr−1 in the Saguenay River and, by extrapolation, of (1.9–8.1) × 108 mol yr−1 in the global ocean. AQYCH4 changed little with photobleaching under air saturation but increased exponentially under suboxic conditions. Spectrally, AQYCH4 decreased sequentially from UVB to UVA to VIS, with UVB being more efficient under suboxic conditions than under oxic conditions. On a depth-integrated basis, VIS prevailed over UVB in controlling CH4 photoproduction under air saturation while the opposite held true under O2-deficiency. An addition of micromolar levels of dissolved dimethyl sulfide (DMS) substantially increased CH4 photoproduction, particularly under O2-deficiency; DMS at nanomolar ambient concentrations in surface oceans is, however, unlikely a significant CH4 precursor. Results from this study suggest that CDOM-based CH4 photoproduction only marginally contributes to the CH4 supersaturation in modern surface oceans and to both the modern and Archean atmospheric CH4 budgets, but that the photochemical term can be comparable to microbial CH4 oxidation in modern oxic oceans. Our results also suggest that anoxic microniches in particulate organic matter and phytoplankton cells containing elevated concentrations of precursors of the methyl radical such as DMS may provide potential hotspots for CH4 photoproduction.

scholarly journals Surface water treatment by UV/H2O2 with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity

2019 ◽  
Vol 5 (10) ◽  
pp. 1709-1722 ◽  
Author(s):  
Robin Wünsch ◽  
Julia Plattner ◽  
David Cayon ◽  
Fabienne Eugster ◽  
Jens Gebhardt ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biological Activity ◽  
Water Treatment ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Microbial Activity ◽  
Soil Aquifer Treatment ◽  
Organic Micropollutants ◽  
Total Removal ◽  
Surface Water Treatment

UV/H2O2 treatment of sand-filtered surface water before soil aquifer treatment increases the total removal of organic micropollutants and has an impact on microbial activity without pronounced effects on dissolved organic matter removal.

scholarly journals Methylphosphonate Oxidation inProchlorococcusStrain MIT9301 Supports Phosphate Acquisition, Formate Excretion, and Carbon Assimilation into Purines

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Oscar A. Sosa ◽  
John R. Casey ◽  
David M. Karl
Keyword(s):  
Organic Matter ◽  
Atlantic Ocean ◽  
Dissolved Organic Matter ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Carbon Assimilation ◽  
Unicellular Cyanobacterium ◽  
Content Type ◽  
The North ◽  
Oxidative Pathway

ABSTRACTThe marine unicellular cyanobacteriumProchlorococcusis an abundant primary producer and widespread inhabitant of the photic layer in tropical and subtropical marine ecosystems, where the inorganic nutrients required for growth are limiting. In this study, we demonstrate thatProchlorococcushigh-light strain MIT9301, an isolate from the phosphate-depleted subtropical North Atlantic Ocean, can oxidize methylphosphonate (MPn) and hydroxymethylphosphonate (HMPn), two phosphonate compounds present in marine dissolved organic matter, to obtain phosphorus. The oxidation of these phosphonates releases the methyl group as formate, which is both excreted and assimilated into purines in RNA and DNA. Genes encoding the predicted phosphonate oxidative pathway of MIT9301 were predominantly present inProchlorococcusgenomes from parts of the North Atlantic Ocean where phosphate availability is typically low, suggesting that phosphonate oxidation is an ecosystem-specific adaptation of someProchlorococcuspopulations to cope with phosphate scarcity.IMPORTANCEUntil recently, MPn was only known to be degraded in the environment by the bacterial carbon-phosphorus (CP) lyase pathway, a reaction that releases the greenhouse gas methane. The identification of a formate-yielding MPn oxidative pathway in the marine planctomyceteGimesia maris(S. R. Gama, M. Vogt, T. Kalina, K. Hupp, et al., ACS Chem Biol 14:735–741, 2019,https://doi.org/10.1021/acschembio.9b00024) and the presence of this pathway inProchlorococcusindicate that this compound can follow an alternative fate in the environment while providing a valuable source of P to organisms. In the ocean, where MPn is a major component of dissolved organic matter, the oxidation of MPn to formate byProchlorococcusmay direct the flow of this one-carbon compound to carbon dioxide or assimilation into biomass, thus limiting the production of methane.

scholarly journals Photomineralization and photomethanification of dissolved organic matter in Saguenay River surface water

2015 ◽  
Vol 12 (16) ◽  
pp. 14303-14341 ◽  
Author(s):  
Y. Zhang ◽  
H. Xie
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Dimethyl Sulfide ◽  
Ultraviolet B ◽  
Global Ocean ◽  
Quantum Yields ◽  
Methyl Radical ◽  
Ch4 Production ◽  
Saguenay River

Abstract. Rates and apparent quantum yields of photomineralization (AQYDOC) and photomethanification (AQYCH4) of chromophoric dissolved organic matter (CDOM) in Saguenay River surface water were determined at three widely differing dissolved oxygen concentrations ([O2]) (suboxic, air-saturation, and oxygenated) using simulated-solar radiation. Photomineralization increased linearly with CDOM absorbance photobleaching for all three O2 treatments. Whereas the rate of photochemical dissolved organic carbon (DOC) loss increased with increasing [O2], the ratio of fractional DOC loss to fractional absorbance loss showed an inverse trend. CDOM photodegradation led to a nearly complete mineralization under suboxic conditions but to only a partial mineralization under oxic conditions. AQYDOC determined under oxygenated, suboxic, and air-saturated conditions increased, decreased, and remained largely constant with photobleaching, respectively; AQYDOC obtained under air-saturation with short-term irradiations could thus be applied to longer exposures. AQYDOC decreased successively from ultraviolet B (UVB) to ultraviolet A (UVA) to visible (VIS), which, alongside the solar irradiance spectrum, points to VIS and UVA being the primary drivers for photomineralization in the water column. The photomineralization rate in the Saguenay River was estimated to be 2.31 × 108 mol C yr−1, accounting for only 1 % of the annual DOC input into this system. Photoproduction of CH4 occurred under both suboxic and oxic conditions and increased with decreasing [O2], with the rate under suboxic conditions ~ 7–8 times that under oxic conditions. Photoproduction of CH4 under oxic conditions increased linearly with photomineralization and photobleaching. Under air-saturation, 0.00057 % of the photochemical DOC loss was diverted to CH4, giving a photochemical CH4 production rate of 4.36 × 10−6 mol m−2 yr−1 in the Saguenay River and, by extrapolation, of (1.9–8.1) × 108 mol yr−1 in the global ocean. AQYCH4 changed little with photobleaching under air-saturation but increased exponentially under suboxic conditions. Spectrally, AQYCH4 decreased sequentially from UVB to UVA to VIS, with UVB being more efficient under suboxic conditions than under oxic conditions. On a depth-integrated basis, VIS prevailed over UVB in controlling CH4 photoproduction under air-saturation while the opposite held true under O2-deficiency. An addition of micromolar levels of dissolved dimethyl sulfide (DMS) substantially increased CH4 photoproduction, particularly under O2-deficiency; DMS at nanomolar ambient concentrations in surface oceans is, however, unlikely a significant CH4 precursor. Results from this study suggest that CDOM-based CH4 photoproduction only marginally contributes to the CH4 supersaturation in modern surface oceans and to both the modern and Archean atmospheric CH4 budgets, but that the photochemical term can be comparable to microbial CH4 oxidation in modern oxic oceans. Our results also suggest that anoxic microniches in particulate organic matter and phytoplankton cells containing elevated concentrations of precursors of the methyl radical such as DMS may provide potential hotspots for CH4 photoproduction.

scholarly journals Protein analysis in dissolved organic matter: What proteins from organic debris, soil leachate and surface water can tell us - a perspective

2005 ◽  
Vol 2 (1) ◽  
pp. 75-86 ◽  
Author(s):  
W. X. Schulze
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Protein Analysis ◽  
Mass Spectrometric ◽  
Environmental Research ◽  
Model Organisms ◽  
Water Current ◽  
Soil Leachate ◽  
Protein Pool

Abstract. Mass spectrometry based analysis of proteins is widely used to study cellular processes in model organisms. However, it has not yet routinely been applied in environmental research. Based on observations that protein can readily be detected as a component of dissolved organic matter (DOM), this article gives an example about the possible use of protein analysis in ecology and environmental sciences focusing on different terrestrial ecosystems. At this stage, there are two areas of interest: (1) the identification of phylogenetic groups contributing to the environmental protein pool, and (2) identification of the organismic origin of specific enzymes that are important for ecosystem processes. In this paper, mass spectrometric protein analysis was applied to identify proteins from decomposing plant material and DOM of soil leachates and surface water samples derived from different environments. It is concluded, that mass spectrometric protein analysis is capable of distinguishing phylogenetic origin of proteins from litter protein extracts, leachates of different soil horizons, and from various sources of terrestrial surface water. Current limitation is imposed by the limited knowledge of complete genomes of soil organisms. The protein analysis allows to relate protein presence to biogeochemical processes, and to identify the source organisms for specific active enzymes. Further applications, such as in pollution research are conceivable. In summary, the analysis of proteins opens a new area of research between the fields of microbiology and biogeochemistry.

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