Photochemical Degradation of Dissolved Organic Carbon to Carbon Monoxide in Coastal Seawater

2000 ◽  
pp. 213-229 ◽  
Author(s):  
Keiichi Ohta ◽  
Yayoi Inomata ◽  
Atsushi Sano ◽  
Koichi Sugimura
Keyword(s):  
Carbon Monoxide ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Photochemical Degradation ◽  
Coastal Seawater

scholarly journals Characterizing the origin of excess dissolved organic carbon in coastal seawater using stable carbon isotope and light absorption characteristics

2020 ◽  
Author(s):  
Heejun Han ◽  
Jeomshik Hwang ◽  
Guebuem Kim
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Isotopic Ratio ◽  
Stable Carbon Isotope ◽  
Bacterial Degradation ◽  
Salinity Range ◽  
Stable Carbon ◽  
Reclaimed Land ◽  
Δ13c Values ◽  
Coastal Seawater

Abstract. In order to determine the origins of dissolved organic matter (DOM) occurring in coastal seawater of the Sihwa Lake, South Korea, which is semi-enclosed by a dyke, we measured the stable carbon isotopic ratio of dissolved organic carbon (DOC-δ13C) and optical properties (absorbance and fluorescence) of the DOM in two different seasons (March 2017 and September 2018). The concentrations of DOC were generally higher in lower-salinity waters in both periods, while a significant excess of DOC was observed in 2017 in the same salinity range. The main source of DOC, dependent on salinity, was found to be from marine sediments in the freshwater-seawater mixing zone rather than from terrestrial sources based on the DOC-δ13C values (−20.7±1.2 ‰) and good correlations among DOC, humic-like fluorescent DOM (FDOMH), and NH4+ concentrations. However, the excess DOC observed in 2017 seems to originate from terrestrial sources by direct land-seawater interactions rather than from in-situ biological production, considering the lower DOC-δ13C values (−27.8 ‰ to −22.6 ‰) and higher spectral slope ratio (SR) of light absorbance, without increases in FDOMH and NH4+ concentrations. This terrestrial DOM source could have been exposed to light and bacterial degradation for a long time, resulting in nonfluorescent and low-molecular-weight DOM, as this study area is surrounded by the reclaimed land. Our results suggest that the combination of these biogeochemical tools can be a powerful tracer of coastal DOM sources.

scholarly journals Complementary pathways of dissolved organic carbon removal pathways in clear-water Amazonian ecosystems: photochemical degradation and bacterial uptake

2006 ◽  
Vol 56 (1) ◽  
pp. 8-17 ◽  
Author(s):  
André M. Amado ◽  
Vinicius F. Farjalla ◽  
Francisco de A. Esteves ◽  
Reinaldo L. Bozelli ◽  
Fábio Roland ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Photochemical Degradation ◽  
Clear Water ◽  
Carbon Removal ◽  
Bacterial Uptake

Photochemical degradation of dissolved organic carbon and its impact on the oceanic carbon cycle

Nature ◽  
1991 ◽  
Vol 353 (6339) ◽  
pp. 60-62 ◽  
Author(s):  
Kenneth Mopper ◽  
Xianliang Zhou ◽  
Robert J. Kieber ◽  
David J. Kieber ◽  
Richard J. Sikorski ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Dissolved Organic Carbon ◽  
Photochemical Degradation ◽  
Oceanic Carbon

Production of Carbon Monoxide and Gaseous Hydrocarbons in Seawater: Relation to Dissolved Organic Carbon

Science ◽  
1970 ◽  
Vol 168 (3939) ◽  
pp. 1577-1579 ◽  
Author(s):  
D. F. Wilson ◽  
J. W. Swinnerton ◽  
R. A. Lamontagne
Keyword(s):  
Carbon Monoxide ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Gaseous Hydrocarbons

scholarly journals Spatiotemporal Dynamics of Dissolved Organic Carbon and Freshwater Browning in the Zoige Alpine Wetland, Northeastern Qinghai-Tibetan Plateau

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2453
Author(s):  
Zheyue Zhang ◽  
Jihong Qin ◽  
Hui Sun ◽  
Jiyuan Yang ◽  
Yanyang Liu
Keyword(s):  
Tibetan Plateau ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Surface Waters ◽  
Dry Season ◽  
Spatiotemporal Dynamics ◽  
Photochemical Degradation ◽  
Wet Season ◽  
Alpine Wetland ◽  
Doc Concentration

The concentrations of dissolved organic carbon (DOC) and its light-absorbing fraction (chromophoric dissolved organic matter; CDOM) in surface waters, particularly those draining organic-rich peatlands, have dramatically increased over the past decade due to climate change and human disturbance. To explore the spatiotemporal dynamics of DOC and CDOM in surface waters of the northeastern Qinghai-Tibetan Plateau, we collected water samples from two rivers in the Zoige alpine wetland and from two rivers in its adjacent alpine-gorge region, during wet and dry seasons. DOC concentration ranged from 4.82 mg·L−1 to 47.83 mg·L−1, with a mean value of 15.04 mg·L−1, 2.84 times higher than the global average. The Zoige rivers had higher DOC concentration and highly terrigenous CDOM. Significantly higher DOC concentration was observed for the Zoige rivers in the wet season compared to the dry season. In contrast, the alpine-gorge rivers had higher DOC levels in the dry season. No significant correlations were observed between DOC and CDOM at all rivers due to the influence of autochthonous sources on the alpine-gorge rivers and intensive photochemical degradation of terrigenous DOM in the Zoige rivers. Significant relationships between CDOM and specific ultraviolet absorbance at 254 nm (SUVA254) and between CDOM/DOC and SUVA254 were observed, indicating that the aromaticity of DOM in the rivers was mainly determined by CDOM. Moreover, the DOC/CDOM properties of the Hei River indicate critical human-induced water quality degradation. High DOC level and high browning degree were found in rivers in the Zoige alpine wetland, indicating that large amounts of terrigenous DOC were released to the aquatic systems of the region.

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