Seasonal and spatial constraints of fluorophores in the midwestern Bay of Bengal by PARAFAC analysis of excitation emission matrix spectra

Chari, N.V.H.K.; Sarma, Nittala S.; Pandi, S.; Murthy, K. Narasimha

doi:10.1016/j.ecss.2012.01.012

Cited by 47 publications

(27 citation statements)

References 67 publications

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“…8 (Huguet et al, 2009). The above conclusion is confirmed by the ratio (M + T )/(A + C) and the HIX index, which achieve respectively higher and lower values in the SML than in the SS due to higher fluorescence intensity at a short-wavelength band belonging to marine FDOM components (M and T ) (Chari et al, 2012;Stedmon and Markanger, 2003;Murphy et al, 2010;Mopper and Schults, 1993). The elevated values of HIX in the SS are the evidence of a more advanced humification process of the organic molecules that make the organic molecules more condensed and increase their aromaticity (Zsolnay et al, 1999).…”

Section: The Absorption and Fluorescence Dependencessupporting

confidence: 50%

“…11-16, coincide with low values of S R , ca. 1-1.2 (Zsolnay et al, 1999;Chari et al, 2012). While S 275−295 < S 350−400 indicates the occurrence and predominance of highly condensed matter, as a dominance of and/or terrestrial DOM, with HMW molecules absorbing in a long-wavelength range (Helms et al, 2008;Chen et al, 2011), the lower HIX and higher S R values (S 275−295 > S 350−400 ) indicate the predominance of marinederived low molecular weighted LMW molecules absorbing in a short-wavelength range (Chen et al, 2011).…”

Section: The Absorption and Fluorescence Dependencesmentioning

confidence: 99%

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Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

et al. 2017

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Abstract. The fluorescence and absorption measurements of the samples collected from a surface microlayer (SML) and a subsurface layer (SS), at a depth of 1 m, were studied during three research cruises in the Baltic Sea along with hydrophysical studies and meteorological observations. Several absorption (E 2 : E 3 , S, S R ) and fluorescence (fluorescence intensities at Coble classified peaks: A, C, M, T the ratio (M + T ) / (A + C) , HIX (humification index)) indices of colored and fluorescent dissolved organic matter (CDOM and FDOM) helped to describe the changes in molecular size and weight as well as in composition of organic matter. The investigation allowed the assessment of a decrease in the contribution of two terrestrial components (A and C) with increasing salinity (∼ 1.64 and ∼ 1.89 % in the SML and ∼ 0.78 and ∼ 0.71 % in the SS, respectively) and an increase in components produced in situ (M and T ) with salinity (∼ 0.52 and ∼ 2.83 % in the SML and ∼ 0.98 and ∼ 1.87 % in the SS, respectively). Hence, a component T reveals the biggest relative changes along the transect from the Vistula River outlet to Gdansk Deep, in both the SML and SS, although an increase was higher in the SML than in the SS (∼ 18.5 and ∼ 12.3 %, respectively). The ratio E 2 : E 3 points to greater changes in the molecular weight of CDOM affected by a higher rate of photobleaching in the SML. The HIX index reflects a more advanced stage of humification and condensation processes in the SS. Finally, the results reveal a higher rate of degradation processes occurring in the SML than in the SS. Thus, the specific physical properties of surface active organic molecules (surfactants) may modify, in a specific way, the solar light spectrum entering the sea and a penetration depth of the solar radiation. Research on the influence of surfactants on the physical processes linked to the sea surface becomes an important task, especially in coastal waters and in the vicinity of the river mouths.

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Section: The Absorption and Fluorescence Dependencessupporting

confidence: 50%

Section: The Absorption and Fluorescence Dependencesmentioning

confidence: 99%

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

et al. 2017

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“…susceptible to photodegradation (Chari, Sarma, Pandi, & Murthy, 2012;Helms et al, 2013;Ishii & Boyer, 2012). However, all these processes take place simultaneously, making it difficult to assign a directional change in the case of C1.…”

Section: Cdom and Fdom Optical Properties: Interactive Effects Of Wmentioning

confidence: 99%

Interplay between climate and hydrogeomorphic features and their effect on the seasonal variation of dissolved organic matter in shallow temperate lakes of the Southern Andes (Patagonia, Argentina): a field study based on optical properties

et al. 2017

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This study analyses the effects of the interplay between climate seasonality and hydrogeomorphic (HGM) lake features on dissolved organic matter (DOM) properties in two neighbouring shallow lakes of Andean Patagonia with different connectivities. The survey was conducted over three years at the end of the wet and dry seasons, assessing the seasonal and interannual variation of dissolved organic carbon (DOC) concentration, whole-lake DOC mass, and DOM quality, through chromophoric and fluorescent DOM (CDOM and FDOM, respectively) properties. During the wet season (fall-winter), precipitation and runoff increased water discharge, water level, and inputs of terrestrial DOM with high aromaticity, humic content, and high molecular weight in both lakes. Contrastingly, during the dry season (spring-summer), in which photodegradation promoted by high irradiance and stagnant conditions drove DOM transformation, nonhumic, low-molecular-weight DOM prevailed. Both lakes displayed synchronicity in their DOC mass and CDOM and FDOM properties, indicative of similar responses to climate forcing, although the overall impact was modulated by their HGM features. Conversely, DOC concentration showed asynchronous responses between lakes, due to the higher intensity of the dilution or evapoconcentration processes in the connected lake, highlighting that DOC concentration is not always sensitive to climate-driven forces. Overall, this study emphasizes the importance of variables other than DOC concentration, like whole-lake DOC mass, DOM quality, and HGM features, to better understand the effect of climate variability on DOM dynamics. Our results allow inferring the potential impact of an environmental scenario characterized by lower precipitation and sustained warming on DOM dynamics in Northern Andean Patagonia.

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“…Across all the three samples, protein-like fluorophores (which are believed to be from autochthonous sources [70]) are present, along with less intense humic (Ex/Em 237-260/380-500 nm range [43]) signatures. In the Ex/ Em 270-280/320-350 nm range, Tryptophan-protein-like substances (TPLS) increased in concentration after WP, compared to both WAS and ER samples.…”

Section: Soluble Codmentioning

confidence: 99%

“…Additionally, the Tyrosine-like fluorophore (Ex/Em 225-237/309-221 nm range [43]) appears. When dissolved organic matter is degraded, Tyrosine-like residue are exposed [70].…”

Section: Soluble Codmentioning

confidence: 99%

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

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Worm predation (WP) on activated sludge leads to increased sludge degradation rates, irrespective of the type of worm used or reactor conditions employed. However, the cause of the increased sludge degradation rates remains unknown. This paper presents a comparative analysis of the physical and biochemical aspects of predated sludge, providing insight into the hydrolytic mechanisms underlying WP. To this end, the sessile worm Tubifex tubifex was used as a model oligochaete and was batch cultivated in an 18-L airlift reactor. Predation on activated sludge showed an average reduction rate of 12 ± 3.8%/d versus 2 ± 1.3%/d for endogenous respirated sludge. Sludge predation resulted in an increased release of inorganic nitrogen, phosphate and soluble chemical oxygen demand (sCOD). The sCOD consisted mainly of polysaccharides; however, fluorescence excitation emission matrix spectroscopy analysis also revealed the presence of Tryptophan-protein-like substances. Results suggest that the released polysaccharides contain a protein-like element. Additionally, soluble iron increased slightly in concentration after WP. The extent of hydrolysis seemed to reach an average plateau of about 40% volatile solids (VS) reduction after 4 days, which is substantially higher than the 29% VS reduction for endogenous decay of activated sludge after 30 days. Furthermore, T. tubifex predominantly consumed the protein fraction of the extracellular polymeric substances. Results suggest that that the worms specifically target a fraction of the sludge that is predominantly biodegradable under aerobic conditions, albeit at significantly higher degradation rates when compared to the endogenous decay of waste activated sludge. ARTICLE HISTORY

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Seasonal and spatial constraints of fluorophores in the midwestern Bay of Bengal by PARAFAC analysis of excitation emission matrix spectra

Cited by 47 publications

References 67 publications

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

Interplay between climate and hydrogeomorphic features and their effect on the seasonal variation of dissolved organic matter in shallow temperate lakes of the Southern Andes (Patagonia, Argentina): a field study based on optical properties

Physical and biochemical changes in sludge uponTubifex tubifexpredation

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