Characteristics, Sources, and Seasonal Variability of Dissolved Organic Matter (DOM) in the Ganges River, Bangladesh

2021 ◽  
Author(s):  
Nahin Mostofa Niloy ◽  
Md. Morshedul Haque ◽  
Shafi M Tareq
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Ganges River ◽  
The Ganges

scholarly journals Spatio-seasonal variability of chromophoric dissolved organic matter absorption and responses to photobleaching in a large shallow temperate lake

2017 ◽  
Vol 14 (5) ◽  
pp. 1215-1233 ◽  
Author(s):  
María Encina Aulló-Maestro ◽  
Peter Hunter ◽  
Evangelos Spyrakos ◽  
Pierre Mercatoris ◽  
Attila Kovács ◽  
...  
Keyword(s):  
Organic Matter ◽  
Optical Properties ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Chromophoric Dissolved Organic Matter ◽  
Lake Balaton ◽  
Spectral Slope ◽  
Marked Variability ◽  
Rich Material ◽  
Development And Validation

Abstract. The development and validation of remote-sensing-based approaches for the retrieval of chromophoric dissolved organic matter (CDOM) concentrations requires a comprehensive understanding of the sources and magnitude of variability in the optical properties of dissolved material within lakes. In this study, spatial and seasonal variability in concentration and composition of CDOM and the origin of its variation was studied in Lake Balaton (Hungary), a large temperate shallow lake in central Europe. In addition, we investigated the effect of photobleaching on the optical properties of CDOM through in-lake incubation experiments. There was marked variability throughout the year in CDOM absorption in Lake Balaton (aCDOM(440) = 0. 06–9.01 m−1). The highest values were consistently observed at the mouth of the main inflow (Zala River), which drains humic-rich material from the adjoining Kis-Balaton wetland, but CDOM absorption decreased rapidly towards the east where it was consistently lower and less variable than in the westernmost lake basins. The spectral slope parameter for the interval of 350–500 nm (SCDOM(350–500)) was more variable with increasing distance from the inflow (observed range 0.0161–0.0181 nm−1 for the mouth of the main inflow and 0.0158–0.0300 nm−1 for waters closer to the outflow). However, spatial variation in SCDOM was more constant exhibiting a negative correlation with aCDOM(440). Dissolved organic carbon (DOC) was strongly positively correlated with aCDOM(440) and followed a similar seasonal trend but it demonstrated more variability than either aCDOM or SCDOM with distance through the system. Photobleaching resulting from a 7-day exposure to natural solar UV radiation resulted in a marked decrease in allochthonous CDOM absorption (7.04 to 3.36 m−1, 42 % decrease). Photodegradation also resulted in an increase in the spectral slope coefficient of dissolved material.

Seasonal variability in chromophoric dissolved organic matter in the Sakawa River and Sagami Bay, Japan

Limnology ◽  
2007 ◽  
Vol 8 (3) ◽  
pp. 211-217 ◽  
Author(s):  
Akira Koyama ◽  
Victor S. Kuwahara ◽  
Akira Shibata ◽  
Tatsuki Toda ◽  
Tomohiko Kikuchi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Chromophoric Dissolved Organic Matter ◽  
Sagami Bay

scholarly journals Use of optical absorption indices to assess seasonal variability of dissolved organic matter in Amazon floodplain lakes

2020 ◽  
Vol 17 (21) ◽  
pp. 5355-5364
Author(s):  
Maria Paula da Silva ◽  
Lino A. Sander de Carvalho ◽  
Evlyn Novo ◽  
Daniel S. F. Jorge ◽  
Claudio C. F. Barbosa
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Optical Absorption ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Large Scale ◽  
Remote Sensing Data ◽  
Floodplain Lakes ◽  
Sentinel 2

Abstract. Given the importance of dissolved organic matter (DOM) in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. In this study we assess the use of optical absorption indices available in the literature based on in situ data to both characterize the seasonal variability of DOM in a highly complex environment and for application in large-scale studies using remote sensing data. The study area comprises four lakes located in the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of colored dissolved organic matter (CDOM) and measurements of remote sensing reflectance (Rrs) were acquired in situ. The Rrs was used to simulate the response of the visible bands of the Sentinel-2 MultiSpectral Instrument (MSI), which was used in the proposed models. Differences between lakes were tested using the CDOM indices. The results highlight the role of the flood pulse in the DOM dynamics at the floodplain lakes. The validation results show that the use of the absorption coefficient of CDOM (aCDOM) as a proxy of the spectral slope between 275 and 295 nm (S275–295) during rising water is worthwhile, demonstrating its potential application to Sentinel-2 MSI imagery data for studying DOM dynamics on the large scale.

scholarly journals Use of absorption optical indices to assess seasonal variability of dissolved organic matter in amazon floodplain lakes

2019 ◽  
Author(s):  
Maria Paula da Silva ◽  
Lino A. Sander de Carvalho ◽  
Evlyn Novo ◽  
Daniel S. F. Jorge ◽  
Claudio C. F. Barbosa
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Large Scale ◽  
River Bank ◽  
In Situ Data ◽  
Amazon Floodplain ◽  
Significant Difference

Abstract. Given the importance of DOM in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. This study assesses the use of available absorption optical indices based on in situ data to both characterize the seasonal variability of the DOM dynamics in a highly complex environment and their viability of being used for satellite remote sensing on large scale studies. The study area comprises four lakes located at the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of coloured dissolved organic matter (CDOM) and remote sensing reflectance (Rrs) were acquired in situ. The Rrs was applied to simulate MSI visible bands and used in the proposed models. Differences between lakes were tested regarding CDOM indices. Significant difference in the average of aCDOM (440), aCDOM spectra and S275–295 were found between lakes located inside the flood forest and those near the river bank. The proposed model showed that aCDOM can be used as proxy of S275–295 during rising water with good validation results, demonstrating the potential of Sentinel/MSI imagery data in large scale studies on the dynamics of DOM.

scholarly journals Spatio-seasonal variability of chromophoric dissolved organic matter absorption and responses to photobleaching in a large shallow temperate lake

2016 ◽  
Author(s):  
María Encina Aullo-Maestro ◽  
Peter Hunter ◽  
Evangelos Spyrakos ◽  
Pierre Mercatoris ◽  
Attila Kovács ◽  
...  
Keyword(s):  
Organic Matter ◽  
Optical Properties ◽  
Dissolved Organic Matter ◽  
Seasonal Variability ◽  
Lake Balaton ◽  
Spectral Slope ◽  
Marked Variability ◽  
Dissolved Matter ◽  
Rich Material ◽  
Development And Validation

Abstract. The development and validation of remote sensing-based approaches for the retrieval of CDOM concentrations requires a comprehensive understanding of the sources and magnitude of variability in the optical properties of dissolved material within lakes. In this study, spatial and seasonal variability in concentration and composition of CDOM and the origin of its variation was studied in Lake Balaton (Hungary), a large temperate shallow lake in central Europe. In addition, we investigated the effect of photobleaching on the optical properties of CDOM through in-lake incubation experiments. There was marked variability throughout the year in CDOM absorption in Lake Balaton (aCDOM (440) = 0.06–9.01 m−1). The highest values were consistently observed at the mouth of the main inflow (River Zala), which drains humic-rich material from the adjoining Kis-Balaton wetland, but CDOM absorption decreased rapidly towards the east where it was consistently lower and less variable than in the westernmost lake basins. The spectral slope parameter for the interval of 350–500 nm (SCDOM(350–500)) was more variable with increasing distance from the inflow (observed range 0.0161–0.0181 nm−1 for the mouth of the main inflow and 0.0158–0.0300 nm−1 for waters closer to the outflow). However, spatial variation in SCDOM was more constant exhibiting a negative correlation with aCDOM(440). DOC was strongly positively correlated with aCDOM(440) and followed a similar seasonal trend but it demonstrated more variability than either aCDOM or SCDOM with distance through the system. Photobleaching resulting from 7 days exposure to natural solar UV radiation resulted in a marked decrease in allochthonous CDOM absorption (7.04 to 3.36 m−1, 42 % decrease) and an even greater decrease in the absorption of autochthonous CDOM (1.34 to 0.312 m−1, 77 % decrease). Photodegradation also resulted in an increase in the spectral slope coefficient of dissolved material. Terrestrial subsidies of dissolved organic matter are known to exert a profound influence over the biogeochemistry and metabolism of lakes. The results from this study show that localized inputs of dissolved matter from wetlands can exert a strong influence over the spatial and seasonal dynamics of CDOM in lakes.

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