scholarly journals Technical note: Effects of iron(II) on fluorescence properties of dissolved organic matter at circumneutral pH

2020 ◽  
Author(s):  
Anonymous
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Technical Note ◽  
Fluorescence Properties ◽  
Circumneutral Ph

scholarly journals Technical note: Effects of iron(II) on fluorescence properties of dissolved organic matter at circumneutral pH

2020 ◽  
Author(s):  
Kun Jia ◽  
Cara C. Manning ◽  
Ashlee Jollymore ◽  
Roger D. Beckie
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Redox Status ◽  
Technical Note ◽  
Component Distribution ◽  
Quenching Effect ◽  
Parafac Model ◽  
Groundwater Samples ◽  
Non Linear ◽  
Parallel Factor

Abstract. Modern fluorescence spectroscopy methods, including excitation-emission matrix (EEMs) spectra parsed using parallel factor analysis (PARAFAC) statistical approaches, are widely used to characterize dissolved organic matter (DOM) pools. The effect of soluble reduced iron, Fe(II), on EEM spectra can be significant, but is difficult to quantitatively assign. In this study, we examine the effects of Fe(II) on the EEM spectra of groundwater samples from an anaerobic deltaic aquifer containing up to 300 mg/L Fe(II), located a few kilometers from the ocean, adjacent to the Fraser River in Richmond, British Columbia, Canada. We added varying quantities of Fe(II) into groundwater samples to evaluate Fe(II)-DOM interactions. Both the overall fluorescence intensity and the intensity of the primary peak, a humic-like substance at excitation/emission wavelengths 239/441–450 nm (Peak A), decreased by approximately 60 % as Fe(II) concentration increased from 1 to 306 mg/L. Furthermore, the quenching effect was non-linear and proportionally stronger at Fe(II) concentrations below 100 mg/L. This non-linear relationship suggests a static quenching mechanism. In addition, DOM fluorescence indices are substantially influenced by the Fe(II) concentration. With increasing Fe(II), the fluorescence index (FI) tends to shift to a more microbial-derived origin, and both the humidification index (HIX) and freshness index (FrI) indicate more freshly produced DOM. Nevertheless, the 13-component PARAFAC model showed that the component distribution was relatively insensitive to Fe(II) concentration, and thus, PARAFAC may be a reliable method for obtaining information about the DOM composition and its redox status in Fe(II)-rich waters. By characterizing the impacts of up to 300 mg/L Fe(II) on EEMs using groundwater from an aquifer which contains similar Fe(II) concentrations, we advance previous works which characterized impacts of lower Fe(II) concentrations (less than 2 mg/L) on EEMs.

Spatio-temporal variations of fluorescence properties of dissolved organic matter along the River Têt (Pyrénées-Orientales, France)

2009 ◽  
Vol 25 (6) ◽  
pp. 435-452 ◽  
Author(s):  
Florence Vouvé ◽  
Leticia Cotrim da Cunha ◽  
Léon Serve ◽  
Jean Vigo ◽  
Jean-Marie Salmon
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Temporal Variations ◽  
Fluorescence Properties ◽  
Spatio Temporal

Seasonal and spatial variations in characteristics of Lake Biwa dissolved organic matter: sorption of pyrene and its derivatives and fluorescence properties

2008 ◽  
Vol 58 (8) ◽  
pp. 1609-1614
Author(s):  
T. Kusakabe ◽  
K. Ikeda ◽  
Y. Shimizu ◽  
S. Higashi ◽  
Y. Kawabata ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Lake Biwa ◽  
Vertical Mixing ◽  
Three Dimensional ◽  
Spatial Variations ◽  
Fluorescence Properties ◽  
Sorption Coefficient ◽  
Suwannee River Fulvic Acid ◽  
Seasonal And Spatial Variations

The objectives of this research were to investigate seasonal and spatial variations in (1) sorption of pyrene and its derivatives onto dissolved organic matter (DOM) and (2) fluorescence properties of DOM in Lake Biwa, Japan. In the case of pyrene, sorption coefficient (Kdoc) of Lake Biwa DOM seasonally changed from 1,200 to 3,800 L/kgC. Vertical distribution of Kdoc was affected by thermocline formation in summer, while it was uniformly distributed as a result of vertical mixing in winter. Functional groups affected sorption of pyrene onto Lake Biwa DOM in different manner from that onto Suwannee River fulvic acid. Three-dimensional excitation emission matrices (3D-EEMs) fluorescence spectroscopy was applied to characterize Lake Biwa DOMs and indicated the existence of at least two fluorophores. The two major peaks at Ex230/Em300 and Ex230/Em425 originated from protein-like and fulvic/humic-like substances, respectively. The peak at Ex230/Em300 showed the maximum fluorescence intensity at a depth of 5 m and could be affected by stratification of the water column in summer. On the other hand, the peak at Ex230/Em425 showed similar profiles both in summer and in winter. These results demonstrably showed that sorption of micropollutants and fluorescence properties of Lake Biwa DOMs were seasonally and spatially varied.

scholarly journals Technical Note: Dissolved organic matter fluorescence – a finite mixture approach to deconvolve excitation-emission matrices

2013 ◽  
Vol 10 (3) ◽  
pp. 4711-4732 ◽  
Author(s):  
A. Butturini ◽  
E. Ejarque
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Heterogeneous Data ◽  
Technical Note ◽  
Laplacian Operator ◽  
Data Set ◽  
Mathematical Algorithm ◽  
Optimal Output ◽  
Mixture Model Approach ◽  
Excitation Emission Matrices

Abstract. The analysis of the shape of excitation-emission matrices (EEMs) is a relevant tool for exploring the origin, transport and fate of dissolved organic matter (DOM) in aquatic ecosystems. Within this context, the decomposition of EEMs is acquiring a notable relevance. A simple mathematical algorithm that automatically deconvolves single EEM is described, creating new possibilities for the comparison of DOM fluorescence properties and EEMs that are very different from each other. A mixture model approach is adopted to decompose complex surfaces into sub-peaks. The laplacian operator and the Nelder–Mead optimization algorithm are implemented to individuate and automatically locate potential peaks in the EEM landscape. A small heterogeneous data set of 21 EEMs from a human-impacted Mediterranean river is used to describe the model application and to illustrate a strategy that optimises the search for the optimal output.

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