Chromophoric dissolved organic matter (CDOM) variability in Barataria Basin using excitation–emission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC)

Singh, Shatrughan; D’Sa, Eurico J.; Swenson, Erick M.

doi:10.1016/j.scitotenv.2010.03.044

Cited by 213 publications

(83 citation statements)

References 40 publications

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“…The fluorescence spectra were corrected for instrument bias using correction files provided by the instrument manufacturer. Normalization of fluorescence intensity was carried out according to the method described in Singh et al (2010). Re-absorption and inner filter effects were minimal as the absorbance values were < 0.02 at 250 nm for the samples analyzed.…”

Section: Eem Measurements and Parafac Model Analysismentioning

confidence: 99%

“…Recent experiments however have shown that phytoplankton can directly contribute to the autochthonous production of marine humic-like substances (Romera-Castillo et al, 2010). The combination of EEMs with parallel factor analysis (PARAFAC) allows for the chemical identification of fluorophores (Stedmon et al, 2003;Stedmon and Markager, 2005a;Stedmon and Bro, 2008;Kowalczuk et al, 2009;Singh et al, 2010). PARAFAC decomposes an EEM data set into least-squares sum of several mathematically independent components to efficiently resolve and identify the different classes of fluorophores in an environment.…”

Section: Introductionmentioning

confidence: 99%

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Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

et al. 2014

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Abstract. The absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are reported for the inner shelf, slope waters and outer shelf regions of the eastern Bering Sea during the summer of 2008, when a warm, thermally stratified surface mixed layer lay over a cold pool (< 2 • C) that occupied the entire middle shelf. CDOM absorption at 355 nm (a g 355) and its spectral slope (S) in conjunction with excitationemission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC) revealed large variability in the characteristics of CDOM in different regions of the Bering Sea. PARAFAC analysis aided in the identification of three humic-like (components one, two and five) and two proteinlike (a tyrosine-like component three, and a tryptophanlike component four) components. In the extensive shelf region, average absorption coefficients at 355 nm (a g 355, m −1 ) and DOC concentrations (µM) were highest in the inner shelf (0.342 ± 0.11 m −1 , 92.67 ± 14.60 µM) and lower in the middle (0.226 ± 0.05 m −1 , 78.38 ± 10.64 µM) and outer (0.185 ± 0.05 m −1 , 79.24 ± 18.01 µM) shelves, respectively. DOC concentrations, however were not significantly different, suggesting CDOM sources and sinks to be uncoupled from DOC. Mean spectral slopes S were elevated in the middle shelf (24.38 ± 2.25 µm −1 ) especially in the surface waters (26.87 ± 2.39 µm −1 ) indicating high rates of photodegradation in the highly stratified surface mixed layer, which intensified northwards in the northern middle shelf likely contributing to greater light penetration and to phytoplankton blooms at deeper depths. The fluorescent humic-like components one, two, and five were most elevated in the inner shelf most likely from riverine inputs. Along the productive "green belt" in the outer shelf/slope region, absorption and fluorescence properties indicated the presence of fresh and degraded autochthonous DOM. Near the Unimak Pass region of the Aleutian Islands, low DOC and a g 355 (mean 66.99 ± 7.94 µM; 0.182 ± 0.05 m −1 ) and a high S (mean 25.95 ± 1.58 µm −1 ) suggested substantial photobleaching of the Alaska Coastal Water, but high intensities of humic-like and protein-like fluorescence suggested sources of fluorescent DOM from coastal runoff and glacier meltwaters during the summer. The spectral slope S vs. a g 355 relationship revealed terrestrial and oceanic end members along with intermediate water masses that were modeled using nonlinear regression equations that could allow water mass differentiation based on CDOM optical properties. Spectral slope S was negatively correlated (r 2 = 0.79) with apparent oxygen utilization (AOU) for waters extending from the middle shelf into the deep Bering Sea indicating increasing microbial alteration of CDOM with depth. Although our data show that the CDOM photochemical environment of the Bering Sea is complex, our current information on its optical properties will aid in better understanding of the biogeochemical role of CDOM in carbon budgets in relation to the annual sea ic...

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Section: Eem Measurements and Parafac Model Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

et al. 2014

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“…By applying the EEMs/PARAFAC technique, the distribution and dynamics of fluorescent DOM have been studied in a wide range of environments varying from lakes (Zhang et al, 2009), estuaries (Stedmon and Markager, 2005;Singh et al, 2010), coastal and shelf (Murphy et al, 2008;Kowalczuk et al, 2010;Para et al, 2010) to pelagic waters (Yamashita et al, 2010;Jørgensen et al, 2011;Kowalczuk et al, 2013). In coastal regions, especially in areas close to river outflows, the riverine input, and its mixing with marine waters are the major factors controlling the distribution and composition of DOM (Stedmon and Markager, 2003;Guo et al, 2007;Alling et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

From Fresh to Marine Waters: Characterization and Fate of Dissolved Organic Matter in the Lena River Delta Region, Siberia

et al. 2015

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Connectivity between the terrestrial and marine environment in the Artic is changing as a result of climate change, influencing both freshwater budgets, and the supply of carbon to the sea. This study characterizes the optical properties of dissolved organic matter (DOM) within the Lena Delta region and evaluates the behavior of DOM across the fresh water-marine gradient. Six fluorescent components (four humic-like; one marine humic-like; one protein-like) were identified by Parallel Factor Analysis (PARAFAC) with a clear dominance of allochthonous humic-like signals. Colored DOM (CDOM) and dissolved organic carbon (DOC) were highly correlated and had their distribution coupled with hydrographical conditions. Higher DOM concentration and degree of humification were associated with the low salinity waters of the Lena River. Values decreased toward the higher salinity Laptev Sea shelf waters. Results demonstrate different responses of DOM mixing in relation to the vertical structure of the water column, as reflecting the hydrographical dynamics in the region. Two mixing curves for DOM were apparent. In surface waters above the pycnocline there was a sharper decrease in DOM concentration in relation to salinity indicating removal. In the bottom water layer the DOM decrease within salinity was less. We propose there is a removal of DOM occurring primarily at the surface layer, which is likely driven by photodegradation and flocculation.

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“…The EEMs spectra were obtained after correction of the fluorescence spectra for instrument bias, and the water Raman normalization of the fluorescence intensity (Singh et al, 2010;D'Sa et al, 2014). Due to low absorbance of the samples, there was no requirement for inner filter correction of the fluorescence data.…”

Section: Eems Measurements and Parafac Analysismentioning

confidence: 99%

Surface Gradients in Dissolved Organic Matter Absorption and Fluorescence Properties along the New Zealand Sector of the Southern Ocean

D’Sa

Kim

2017

Front. Mar. Sci.

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The Southern Ocean plays a critical role in the global carbon cycle; dissolved organic matter (DOM), a component in the carbon cycling, can be characterized optically. Sea surface chromophoric dissolved organic matter (CDOM) absorption and fluorescence properties were examined in the New Zealand sector of the Southern Ocean (NZSSO) along a transect encompassing various hydrographic fronts associated with the Antarctic Circumpolar Current (ACC) during summer. Phytoplankton chlorophyll, dissolved organic carbon (DOC) and CDOM absorption were observed to be most elevated off the New Zealand shore and then decreased to low values [chlorophyll: 0.21 ± 0.06 mg m −3 ; DOC: 54.19 ± 4.02 µM, and CDOM absorption coefficient at 325 nm (a g 325): 0.097 ± 0.061 m −1 ] between the Subtropical (STF) and Antarctic Polar (APF) Fronts. Increases in phytoplankton biomass and DOC concentrations between the fronts were associated with meanders or eddies observed in satellite sea surface salinity and chlorophyll imagery. Overall, CDOM absorption was the dominant contributor to total absorption at 443 nm with implications for ocean color. Beyond the APF in the Antarctic Zone, an elevated chlorophyll band likely associated with upwelled waters transitioned to low chlorophyll in the summer ice edge zone that influenced DOM optical properties. A latitudinal increase in a g 325 and corresponding decrease in spectral slope S (µm −1 ) poleward from the STF could be due to a combination of factors including, decreasing CDOM photooxidation, upwelling of high-CDOM waters or bacterial CDOM production in the Antarctic Zone. Parallel factor analysis (PARAFAC) of fluorescence spectra identified two protein-like (C1 and C2) and two humic-like (C3 and C4) components common in the global ocean. a g 325 and the humic-like C4 fluorescent component were positively correlated to chlorophyll, indicating biological control. Surface distribution of the protein-like C1 and C2 and the marine humic-like C3 components showed patterns that appeared to be influenced by both physical and biological processes. This study provides insights into surface CDOM optical properties and its transformation along a complex topographically influenced sector of the Southern Ocean that could be used to trace changes linked to the meridional overturning circulation.

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Chromophoric dissolved organic matter (CDOM) variability in Barataria Basin using excitation–emission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC)

Cited by 213 publications

References 40 publications

Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

From Fresh to Marine Waters: Characterization and Fate of Dissolved Organic Matter in the Lena River Delta Region, Siberia

Surface Gradients in Dissolved Organic Matter Absorption and Fluorescence Properties along the New Zealand Sector of the Southern Ocean

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