Origin, distributions, and environmental significance of ubiquitous humic-like fluorophores in Antarctic lakes and streams

Kida, Morimaru; Kojima, Taichi; Tanabe, Yukiko; Hayashi, Kentaro; Kudoh, Sakae; Maie, Nagamitsu

doi:10.1016/j.watres.2019.114901

Cited by 91 publications

(69 citation statements)

References 42 publications

(71 reference statements)

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“…Some information, including the locations of peaks, the maximum intensity of fluorescence, components' categories, and primary compounds of PARAFAC components are summarized in Table 1. Through their comparison with the OpenFluor database, C1 (Ex/Em: 250-310/420 nm), C2 (Ex/Em: 262/ 470 nm), C3 (Ex/Em: 280/496 nm), and C4 (Ex/Em: 222/ 302 nm) were categorized here, respectively, as a fulvic-like component composed of both carboxylic-like and phenoliclike chromophores, a terrestrial humic-like component primarily composed of carboxylic-like chromophores, a microbial humic-like component mostly composed of phenolic-like fluorophores, and a protein-like component (Murphy et al, 2011;Yan et al, 2013;Derrien et al, 2019;Kida et al, 2019). The Em wavelength was longer for C3 than C2, which meant the microbial humic-like components harbored greater aromaticity and a larger scale for the π -conjugated system than did the terrestrial humic-like component (Yu et al, 2020).…”

Section: Parafac Analysis Of Hssmentioning

confidence: 99%

“…(Kitis et al, 2001). The photochemical reactivity of DOM produces dissolved inorganic carbon (Gao, 1998), in addition to organic molecules of low molecular weight (Kulovaara, 1996;Gonsior et al, 2014) and complex aromatic structures (Timko et al, 2015), all of which could influence the toxicity, mobility, and transformation of aquatic contaminants (Kida et al, 2019). Many previous studies have focused on the photodegradation of non-purified DOM in natural water (Zhu et al, 2017;Kida et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The photochemical reactivity of DOM produces dissolved inorganic carbon (Gao, 1998), in addition to organic molecules of low molecular weight (Kulovaara, 1996;Gonsior et al, 2014) and complex aromatic structures (Timko et al, 2015), all of which could influence the toxicity, mobility, and transformation of aquatic contaminants (Kida et al, 2019). Many previous studies have focused on the photodegradation of non-purified DOM in natural water (Zhu et al, 2017;Kida et al, 2019). Recently, the photochemical reactivity of DOM samples varying in molecular mass from Yangtze River and its coastal area were examined by excitation-emission matrix (EEM) spectroscopy, which revealed that the highly aromatic humic-like materials exhibited greater photochemical reactivity than did the nonhumic-like materials (Zhu et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the photochemical reactivity of DOM samples varying in molecular mass from Yangtze River and its coastal area were examined by excitation-emission matrix (EEM) spectroscopy, which revealed that the highly aromatic humic-like materials exhibited greater photochemical reactivity than did the nonhumic-like materials (Zhu et al, 2017). Photodegradation was confirmed to be the major external factor driving the compositional diversity of DOM in Antarctic lakes and streams, as assessed using the spectral slope S 275-279 for the distribution of its fluorescence components (Kida et al, 2019). Nonetheless, how photochemical reactivity variously acts upon the structures and functions of HSs is still not well understood; hence, the proper isolation and purification of HSs is critical to elucidate photochemical reactivity mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…For example, this EEM-PARAFAC approach was able to reveal the effect of light on PARAFAC components by exposing the DOM from a sub-alpine lake to three different light sources (Du et al, 2016). Seven PARAFAC components were identified by (Kida et al, 2019), who studied the photodegradation of DOM from 47 lakes and two streams on the ice-free area at Lützow-Holm Bay and Amundsen Bay in East Antarctica. Five primary components in the Yangtze River and two primary components in the Western Pacific Ocean were identified by PARAFAC analysis during irradiation of DOM measured by EEM, the relative abundance of photo-refractory UVC humic-like components was increased during irradiation (Zhu et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

et al. 2021

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The photochemical reactivity of humic substances plays a critical role in the global carbon cycle, and influences the toxicity, mobility, and bioavailability of contaminants by altering their molecular structure and the mineralization of organic carbon to CO2. Here, we examined the simulated irradiation process of Chinese standard fulvic acid (FA) and humic acid (HA) by using excitation-emission matrix fluorescence combined with fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and kinetic models. Humic-like and fulvic-like materials were the main materials (constituting more than 90%) of both FA and HA, according to the FRI analysis. Four components were identified by the PARAFAC analysis: fulvic-like components composed of both carboxylic-like and phenolic-like chromophores (C1), terrestrial humic-like components primarily composed of carboxylic-like chromophores (C2), microbial humic-like overwhelming composed of phenolic-like fluorophores (C3), and protein-like components (C4). After irradiation for 72 h, the maximum fluorescence intensity (Fmax) of C1 and C2 of FA was reduced to 36.01–58.34%, while the Fmax of C3 of both FA and HA also decreased to 0–9.63%. By contrast, for HA, the Fmax of its C1 and C2 increased to 236.18–294.77% when irradiated for 72 h due to greater aromaticity and photorefractive tendencies. The first-order kinetic model (R2 = 0.908–0.990) fitted better than zero-order kinetic model (R2 = 0–0.754) for the C1, C2, and C3, of both FA and HA, during their photochemical reactivity. The photodegradation rate constant (k1) of C1 had values (0.105 for FA; 0.154 for HA) that surpassed those of C2 (0.059 for FA, 0.079 for HA) and C3 (0.079 for both FA and HA) based on the first-order kinetic model. The half-life times of C1, C2, and C3 ranged from 6.61–11.77 h to 4.50–8.81 h for FA and HA, respectively. Combining an excitation-emission matrix with FRI and PARAFAC analyses is a powerful approach for elucidating changes to humic substances during their irradiation, which is helpful for predicting the environmental toxicity of contaminants in natural ecosystems.

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Section: Parafac Analysis Of Hssmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

et al. 2021

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Effects of dissolved organic matter derived from cow manure on heavy metal(loid)s and bacterial community dynamics in mercury-thallium mining waste slag

Luo

Wei

et al. 2023

Environ Geochem Health

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Organic amendments in aided phytostabilization of waste slag contain high levels of heavy metal (loid)s (HMs) is an important way to in situ control the release of HMs. However, the effects of dissolved organic matter (DOM) derived from organic amendments on HMs and microbial community dynamics in waste slag are still unclear. The results showed that the mercury (Hg)-thallium (Tl) mining waste slag without the addition of DOM continuously decreased pH and increased EC, Eh, SO 4 2− , Hg, and Tl in the leachate with increasing incubation time. The addition of DOM signi cantly increased pH, EC, SO 4 2− , and arsenic (As) but decreased Eh, Hg, and Tl. The addition of DOM signi cantly increased the diversity and richness of the bacterial community. The dominant bacterial phyla (Proteobacteria, Firmicutes, Acidobacteriota, Actinobacteriota, and Bacteroidota) and genera (Bacillus, Acinetobacter, Delftia, Sphingomonas, and Enterobacter) were changed in associated with increases in DOM content and incubation time. The DOM components in leachate were humic-like substances (C1 and C2), and the DOM content and maximum uorescence intensity (F Max ) values of components C1 and C2 in the leachate decreased and rst increased and then decreased with increasing incubation time. The correlations between HMs and DOM and the bacterial community showed that the geochemical behaviours of HMs in Hg-Tl mining waste slag were directly in uenced by DOM properties and indirectly in uenced by DOM regulation of bacterial community changes. Overall, these results indicated that DOM properties associated with bacterial community changes increased As but decreased Hg and Tl mobilization from Hg-Tl mining waste slag.

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The importance of allochthonous organic matter quality when investigating pulse disturbance events in freshwater lakes: a mesocosm experiment

et al. 2021

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Extreme precipitation is occurring with greater frequency and intensity as a result of climate change. Such events boost the transport of allochthonous organic matter (allo-OM) to freshwater ecosystems, yet little is known about the impacts on dissolved organic matter (DOM) quality and seston elemental stoichiometry, especially for lakes in warm climates. A mesocosm experiment located in a Turkish freshwater lake was designed to simulate a pulse event leading to increased inputs of allo-OM by examining the individual effects of increasing water colour (HuminFeed®, HF), the direct effects of the extra energetic inputs (alder tree leaf leachate, L), and the interactions of the single treatment effects (combination of both sources, HFL), along with a comparison with unmanipulated controls. Changes in the DOM quality and nutrient stoichiometry of the allo-OM treatment additions was examined over the course of the experiments. Results indicated that there was an increase of high recalcitrant DOM components in the HF treatment, in contrast to an increase in less aromatic microbially derived molecules for the L treatment. Unexpectedly, seston C:P ratios remained below a severe P-limiting threshold for plankton growth and showed the same temporal pattern in all mesocosms. In contrast, seston N:P ratios differed significantly between treatments, with the L treatment reducing P-limiting conditions, whilst the HF treatment increased them. The effects of the combined HFL treatment indicated an additive type of interaction and chlorophyll-a was highest in the HFL treatment. Our results demonstrate that accounting for the optical and stoichiometric properties of experimental allo-OM treatments is crucial to improve the capacity to explain extrapolated conclusions regarding the effects of climate driven flooding on freshwater ecosystems in response to global climate change. Graphical abstract

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Origin, distributions, and environmental significance of ubiquitous humic-like fluorophores in Antarctic lakes and streams

Cited by 91 publications

References 42 publications

Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

Photochemical Reactivity of Humic Substances in an Aquatic System Revealed by Excitation-Emission Matrix Fluorescence

Effects of dissolved organic matter derived from cow manure on heavy metal(loid)s and bacterial community dynamics in mercury-thallium mining waste slag

The importance of allochthonous organic matter quality when investigating pulse disturbance events in freshwater lakes: a mesocosm experiment

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