Dissolved organic fluorophores in southeastern US coastal waters: correction method for eliminating Rayleigh and Raman scattering peaks in excitation–emission matrices

Zepp, Richard G.; Sheldon, Wade M.; Moran, Mary Ann

doi:10.1016/j.marchem.2004.02.006

Cited by 427 publications

(190 citation statements)

References 47 publications

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“…Emission (Em) spectra were collected from 250 to 600 nm at 2 nm intervals at excitation (Ex) wavelengths from 250 to 500 nm at 5 nm intervals. Backgrounds were subtracted for fresh distilled water prepared daily from the sample data to eliminate Raman scatter peaks (Zepp et al, 2004). All data were obtained in counts per second (cps) and converted to a ppb quinine sulfate standard solution in 0.1 N sulfuric acid at Ex / Em of 350 / 450 nm.…”

Section: Methodsmentioning

confidence: 99%

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Lee¹,

Kim²

2018

Biogeosciences

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Abstract. We monitored seasonal variations in dissolved organic carbon (DOC), the stable carbon isotope of DOC (δ 13 C-DOC), and fluorescent dissolved organic matter (FDOM) in water samples from a fixed station in the Nakdong River Estuary, Korea. Sampling was performed every hour during spring tide once a month from October 2014 to August 2015. The concentrations of DOC and humic-like FDOM showed significant negative correlations against salinity (r 2 = 0.42-0.98, p < 0.0001), indicating that the river-originated DOM components were the major source and behave conservatively in the estuarine mixing zone. The extrapolated δ 13 C-DOC values (−27.5 to −24.5 ‰) in fresh water confirm that both components are mainly of terrestrial origin. The slopes of humic-like FDOM against salinity were 60-80 % higher in the summer and fall due to higher terrestrial production of humic-like FDOM. The slopes of proteinlike FDOM against salinity, however, were 70-80 % higher in spring due to higher biological production in river water. Our results suggest that there are large seasonal changes in riverine fluxes of humic-and protein-like FDOM to the ocean.

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Section: Methodsmentioning

confidence: 99%

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Lee¹,

Kim²

2018

Biogeosciences

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“…The scans were standardized to Raman units (normalized to the integral of the Raman signal between 390 and 410 nm in emission at a fixed excitation of 350 nm) with a Milli-Q water sample run the same day as the samples (Zepp et al 2004). PARAFAC model was build using MATLAB (MathWorks, Natick, MA, USA) and the drEEM Toolbox version 1.0 (Murphy et al 2013).…”

Section: Parafac Modelingmentioning

confidence: 99%

Effects of human land use on the terrestrial and aquatic sources of fluvial organic matter in a temperate river basin (The Meuse River, Belgium)

et al. 2017

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The impact of human activities on the concentrations and composition of dissolved organic matter (DOM) and particulate organic matter (POM) was investigated in the Walloon Region of the Meuse River basin (Belgium). Water samples were collected at different hydrological periods along a gradient of human disturbance (50 sampling sites ranging from 8.0 to 20,407 km 2 ) and during a 1.5 year monitoring of the Meuse River at the city of Liège. This dataset was completed by the characterization of the DOM pool in groundwaters. The composition of DOM and POM was investigated through elemental (C:N ratios), isotopic (d 13 C) and optical measurements including excitation emission matrix fluorescence with parallel factor analysis (EEM-PARAFAC). Land use was a major driver on fluvial OM composition at the regional scale of the Meuse Basin, the composition of both fluvial DOM and POM pools showing a shift toward a more microbial/algal and less plant/soil-derived character as human disturbance increased. The comparison of DOM composition between surface and groundwaters demonstrated that this pattern can be attributed in part to the transformation of terrestrial sources by agricultural practices that promote the decomposition of soil organic matter in agricultural lands and subsequent microbial inputs in terrestrial sources. In parallel, human land had contrasting effects on the autochthonous production of DOM and POM. While the in-stream generation of fresh DOM through biological activity was promoted in urban areas, summer autochthonous POM production was not influenced by land use. Finally, soil erosion by agricultural management practices favored the transfer of terrestrial organic matter via the particulate phase. Stable isotope data suggest that the hydrological transfer of terrestrial DOM and POM in humanimpacted catchment are not subject to the same controls, and that physical exchange between these two pools of organic matter is limited.

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“…Scatter can be considered as outlying elements or outliers of the second type, because this scatter does not contain any chemically relevant information and does not follow the tri-linear model. Several ways to handle scatter in relation to PARAFAC modeling can be found in the literature [7,11,[15][16][17][18][19][20][21] but treating scatter as outlying elements leads in Engelen et al [2] to the construction of the automated scatter identification method. The approach can handle both first and second order Rayleigh scatter as well as Raman scatter and require no a priori information about the scatter itself, like for example the placement or the width of the scatter ridges.…”

Section: Introductionmentioning

confidence: 99%

A fully robust PARAFAC method for analyzing fluorescence data

Engelen

Frosch

Jørgensen

2009

Journal of Chemometrics

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Parallel factor analysis (PARAFAC) is a widespread method for modeling fluorescence data by means of an alternating least squares procedure. Consequently, the PARAFAC estimates are highly influenced by outlying excitation-emission landscapes (EEM) and element-wise outliers, like for example Raman and Rayleigh scatter. Recently, a robust PARAFAC method that circumvents the harmful effects of outlying samples has been developed. For removing the scatter effects on the final PARAFAC model, different techniques exist. Newly, an automated scatter identification tool has been constructed. However, there still exists no robust method for handling fluorescence data encountering both outlying EEM landscapes and scatter. In this paper, we present an iterative algorithm where the robust PARAFAC method and the scatter identification tool are alternately performed. A fully automated robust PARAFAC method is obtained in that way. The method is assessed by means of simulations and a laboratory-made data set.

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Dissolved organic fluorophores in southeastern US coastal waters: correction method for eliminating Rayleigh and Raman scattering peaks in excitation–emission matrices

Cited by 427 publications

References 47 publications

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Effects of human land use on the terrestrial and aquatic sources of fluvial organic matter in a temperate river basin (The Meuse River, Belgium)

A fully robust PARAFAC method for analyzing fluorescence data

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