scholarly journals Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties

2016 ◽  
Vol 18 (11) ◽  
pp. 1381-1399 ◽  
Author(s):  
Kristopher McNeill ◽  
Silvio Canonica
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Surface Waters ◽  
Reaction Mechanisms ◽  
Photophysical Properties ◽  
Chromophoric Dissolved Organic Matter ◽  
Triplet States ◽  
Excited Triplet ◽  
Aquatic Photochemistry ◽  
Excited Triplet States

Excited triplet states of chromophoric dissolved organic matter (3CDOM*) play a major role among the reactive intermediates produced upon absorption of sunlight by surface waters.

Photochemistry of dissolved organic matter extracted from coastal seawater: Excited triplet-states and contents of phenolic moieties

2021 ◽  
Vol 188 ◽  
pp. 116568
Author(s):  
Zhongyu Guo ◽  
Jieqiong Wang ◽  
Xi Chen ◽  
Feifei Cui ◽  
Tingting Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Triplet States ◽  
Excited Triplet ◽  
Coastal Seawater ◽  
Excited Triplet States

scholarly journals Triplet State Formation of Chromophoric Dissolved Organic Matter in Atmospheric Aerosols: Characteristics and Implications

2020 ◽  
Author(s):  
Qingcai Chen ◽  
Zhen Mu ◽  
Li Xu ◽  
Mamin Wang ◽  
Jin Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Triplet State ◽  
Atmospheric Aerosols ◽  
Formation Rate ◽  
Chromophoric Dissolved Organic Matter ◽  
Biomass Combustion ◽  
Triplet States ◽  
Ambient Aerosols ◽  
Paramagnetic Resonance

Abstract. There is chromophore dissolved organic matter (CDOM) in the atmosphere, which may form triplet-state chromophoric dissolved organic matter (3CDOM*) to further driving the formation of reactive oxygen species (ROS) under solar illumination. 3CDOM* contributes significantly to aerosol photochemistry and plays an important role in aerosol aging. We quantify the ability to form 3CDOM* and drive the formation of ROS by primary, secondary and ambient aerosols. Biomass combustion has the strongest 3CDOM* generation capacity and the weakest vehicle emission capacity. Ambient aerosol has a stronger ability to generate 3CDOM* in winter than in summer. Most of the triplet states generation conform to first-order reaction, but some of them do not due to the different quenching mechanism. The structural-activity relationship between the CDOM type and the 3CDOM* formation capacity shows that the two types of CDOM identified, which similar to the nitrogen-containing chromophores contributed 88 % to the formation of 3CDOM*. The estimated formation rate of 3CDOM* can reach ~ 100 μmol m−3 h−1 in the atmosphere in Xi'an, China, which is approximately one hundred thousand-times the hydroxyl radical (•OH) production. This study verified that 3CDOM* drives at least 30 % of the singlet oxygen (1O2) and 31 % of the •OH formed by aerosols using the spin trapping and electron paramagnetic resonance technique.

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 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 Quenching of Excited Triplet States by Dissolved Natural Organic Matter

2013 ◽  
Vol 47 (22) ◽  
pp. 12802-12810 ◽  
Author(s):  
Jannis Wenk ◽  
Soren N. Eustis ◽  
Kristopher McNeill ◽  
Silvio Canonica
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Triplet States ◽  
Excited Triplet ◽  
Excited Triplet States
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