Photochemical and microbial alterations of DOM spectroscopic properties in the estuarine system Ria de Aveiro

2014 ◽  
Vol 13 (8) ◽  
pp. 1146-1159 ◽  
Author(s):  
L. Santos ◽  
E. B. H. Santos ◽  
J. M. Dias ◽  
A. Cunha ◽  
A. Almeida
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Brackish Water ◽  
Spectral Characteristics ◽  
Spectroscopic Properties ◽  
Chromophoric Dissolved Organic Matter ◽  
Estuarine System ◽  
Ria De Aveiro

The chromophoric dissolved organic matter (CDOM) of marine (MZ) and brackish water (BZ) zones of Ria de Aveiro showed different spectral characteristics and susceptibility to photochemical alterations, reflecting the different amounts and prevailing sources of organic matter.

scholarly journals Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean

2013 ◽  
Vol 10 (11) ◽  
pp. 7207-7217 ◽  
Author(s):  
Y. Yamashita ◽  
Y. Nosaka ◽  
K. Suzuki ◽  
H. Ogawa ◽  
K. Takahashi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Surface Waters ◽  
Spectral Characteristics ◽  
Open Ocean ◽  
Global Ocean ◽  
Chromophoric Dissolved Organic Matter ◽  
Spectral Slope ◽  
Subtropical Region ◽  
Subarctic Region

Abstract. Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainly controlled by in situ production and photobleaching. However, factors controlling the spectral parameters of CDOM in the UV region, i.e., spectral slope of CDOM determined at 275–295 nm (S275–295) and the ratio of two spectral slope parameters (SR); the ratio of S275–295 to S350–400, have not been well documented. To evaluate the factor controlling the spectral characteristics of CDOM in the UV region in the open ocean, we determined the quantitative and qualitative characteristics of CDOM in the subarctic and subtropical surface waters (5–300 m) of the western North Pacific. Absorption coefficients at 320 nm in the subarctic region were higher than those in the subtropical region throughout surface waters, suggesting that magnitudes of photobleaching were different between the two regions. The values of S275–295 and SR were also higher in the subtropical region than the subarctic region. The dark microbial incubation showed biodegradation of DOM little affected S275–295, but slightly decreased SR. On the other hand, increases in S275–295 and relative stableness of SR were observed during photo-irradiation incubations respectively. These experimental results indicated that photobleaching of CDOM mainly induced qualitative differences in CDOM at UV region between the subarctic and subtropical surface waters. The results of this study imply that S275–295 can be used as a tracer of photochemical history of CDOM in the open ocean.

scholarly journals Influence of environmental factors on spectral characteristic of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China

2015 ◽  
Vol 12 (6) ◽  
pp. 5895-5929 ◽  
Author(s):  
Z. D. Wen ◽  
K. S. Song ◽  
Y. Zhao ◽  
J. Du ◽  
J. H. Ma
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Environmental Factors ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Light Absorption ◽  
Vascular Plant ◽  
Spectral Characteristics ◽  
Chromophoric Dissolved Organic Matter ◽  
River Waters

Abstract. Spectral characteristics of chromophoric dissolved organic matter (CDOM) were examined in conjunction with environmental factors in the waters of 22 rivers and 26 terminal waters in Hulun Buir plateau, northeast China. Dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorous (TP) were significantly higher in terminal waters than rivers waters (p < 0.01). Principal component analysis (PCA) indicated that non-water light absorption and anthropogenic nutrient disturbances might be the causes of the diversity of water quality parameters in Hulun Buir plateau. CDOM absorption in river waters was significantly lower than terminal waters (p < 0.01). Analysis of ratio of absorption at 250–365 nm (E250 : 365), specific UV absorbance (SUVA254), and spectral slope ratio (Sr) indicated that CDOM in river waters had higher aromaticity, molecular weight, and vascular plant contribution than in terminal waters. Furthermore, results showed that DOC concentration, CDOM light absorption, and the proportion of autochthonous sources of CDOM in plateau waters were all higher than in other freshwater rivers reported in the literature. The strong evapoconcentration, intense ultraviolet irradiance and landscape features of Hulun Buir plateau may be responsible for the above phenomenon. Redundancy analysis (RDA) indicated that the environmental variables TSM, TN, and EC had a strong correlation with light absorption characteristics, followed by TDS and chlorophyll a. In most sampling locations, CDOM was the dominant non-water light-absorbing substance. Light absorption by non-algal particles often exceeded that by phytoplankton in the plateau waters. Study of these optical-physicochemical correlations is helpful in the evaluation of the potential influence of water quality factors on non-water light absorption in cold plateau water environments. And the study on organic carbon in plateau lakes had a vital contribution to global carbon balance estimation.

scholarly journals The photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean

2013 ◽  
Vol 10 (6) ◽  
pp. 9989-10019 ◽  
Author(s):  
Y. Yamashita ◽  
Y. Nosaka ◽  
K. Suzuki ◽  
H. Ogawa ◽  
K. Takahashi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Surface Waters ◽  
Spectral Characteristics ◽  
Open Ocean ◽  
Global Ocean ◽  
Chromophoric Dissolved Organic Matter ◽  
Spectral Slope ◽  
Subtropical Region ◽  
Subarctic Region

Abstract. Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainly controlled by in situ production and photo-degradation. However, factors controlling the spectral parameters of CDOM at UV region, i.e., spectral slope of CDOM determined at 275–295 nm (S275–295) and the ratio of two spectral slope parameters (SR; the ratio of S275–295 to S350–400), have not been well documented. To evaluate the factor controlling the spectral characteristics of CDOM at UV region in open ocean, we determined the quantitative and qualitative characteristics of CDOM in the subarctic and subtropical surface waters (5–300 m) of the western North Pacific. Absorption coefficients at 320 nm in the subarctic region were significantly higher than those in the subtropical region throughout surface waters, suggesting that magnitudes of photobleaching were different between the two regions. The values of S275–295 and SR were also significantly higher in the subtropical region than the subarctic region. The dark microbial incubation showed biodegradation of DOM little affected S275–295, but slightly decreased SR. On the other hand, increases and unchanging were observed for S275–295 and SR during photo-irradiation incubations respectively. These experimental results indicated that photobleaching of CDOM mainly induced qualitative differences in CDOM at UV region between the subarctic and subtropical surface waters. The results of this study imply that S275–295 can be used as a tracer of photochemical history of CDOM in open ocean.

scholarly journals UV Absorption Spectral Characteristics of Dissolved Organic Matter in Fen River of Taiyuan in China

2018 ◽  
Vol 53 ◽  
pp. 03027
Author(s):  
Jianhui Zhi ◽  
Shengyu Song
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Spectral Characteristics ◽  
Anthropogenic Pollution ◽  
Uv Absorption ◽  
Chromophoric Dissolved Organic Matter ◽  
Uv Absorbance ◽  
Low Degree ◽  
Doc Concentration ◽  
Main Components

UV absorption is one of the important properties of chromophoric dissolved organic matter (CDOM). The UV absorption spectral characteristics of dissolved organic matter (DOM) were analyzed to infer the main components in Taiyuan urban section. Based on the UV absorption spectral characteristics of the CDOM, and relationship between DOC concentration and UV absorbance, conclusions were drawn: (1) Content of DOM in the treated section was at a low degree and constituent.The anthropogenic pollution accounted for a major role. (2)DOM constituents in Taiyuan section in May, July and November were relatively simple. The molecular structure of mainly CDOM was simple with mostly two or three species among the hydroxyl, carboxyl and phenyl. However, DOM constituent in September was more complicated, there were more non-fluorescent substances besides CDOM.

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