The influence of DEM resolution on simulated solar radiation-induced glacier melt

Abstract. Organic carbon (OC) depleted in 13C is a widely used tracer for terrestrial organic matter (OM) in aquatic systems. Photochemical reactions can, however, change δ13C of dissolved organic carbon (DOC) when chromophoric, aromatic-rich terrestrial OC is selectively mineralized. We assessed the robustness of the δ13C signature of DOC (δ13CDOC) as a tracer for terrestrial OM by estimating its change during the photobleaching of chromophoric DOM (CDOM) from 10 large rivers. These rivers cumulatively account for approximately one-third of the world's freshwater discharge to the global ocean. Photobleaching of CDOM by simulated solar radiation was associated with the photochemical mineralization of 16 to 43% of the DOC and, by preferentially removing compounds depleted in 13C, caused a 1 to 2.9‰ enrichment in δ13C in the residual DOC. Such solar-radiation-induced photochemical isotopic shift could bias the calculations of terrestrial OM discharge in coastal oceans towards the marine end-member. Shifts in terrestrial δ13CDOC should be taken into account when constraining the terrestrial end-member in global calculation of terrestrially derived DOM in the world ocean.

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Revisiting the disappearance of terrestrial dissolved organic matter in the ocean: a δ13C study

Biogeosciences Discussions ◽

10.5194/bgd-10-17117-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 17117-17144

Author(s):

K. Lalonde ◽

A. V. Vähätalo ◽

Y. Gélinas

Keyword(s):

Organic Carbon ◽

Solar Radiation ◽

World Ocean ◽

Photochemical Reactions ◽

Aquatic Systems ◽

Global Ocean ◽

Coastal Oceans ◽

The World ◽

Radiation Induced ◽

Simulated Solar Radiation

Abstract. Organic carbon (OC) depleted in 13C is a widely used tracer for terrestrial OM in aquatic systems. Photochemical reactions can however change δ13C of dissolved organic carbon (DOC) when chromophoric, aromatic-rich terrestrial OC is selectively mineralized. We assessed the robustness of the δ13C signature of DOC (δ13CDOC) as a tracer for terrestrial OM by estimating its change during the photobleaching of chromophoric DOM (CDOM) from ten large rivers. These rivers cumulatively account for approximately 1/3 of the world's freshwater discharge to the global ocean. Photobleaching of CDOM by simulated solar radiation was associated with the photochemical mineralization of 16 to 43% of the DOC and, by preferentially removing compounds depleted in 13C, caused a 1 to 2.9‰ enrichment in δ13C in the residual DOC. Such solar radiation-induced photochemical isotopic shift biases the calculations of terrestrial OM discharge in coastal oceans towards the marine end-member. Shifts in terrestrial δ13CDOC should be taken into account when constraining the terrestrial end-member in global calculation of terrestrially derived DOM in the world ocean.

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Photocatalytic-Fenton Process under Simulated Solar Radiation Promoted by a Suitable Catalyst Selection

Catalysts ◽

10.3390/catal11080885 ◽

2021 ◽

Vol 11 (8) ◽

pp. 885

Author(s):

Aida M. Díez ◽

Helen E. Valencia ◽

Maria Meledina ◽

Joachim Mayer ◽

Yury V. Kolen'ko

Keyword(s):

Methylene Blue ◽

Solar Radiation ◽

Water Scarcity ◽

Published Data ◽

Fenton Process ◽

Optimal Conditions ◽

Operational Conditions ◽

The Future ◽

Simulated Solar Radiation ◽

Catalyst Selection

Considering water scarcity, photo-based processes have been presented as a depollution technique, which should be optimized in order to be applied in the future. For that, the addition of an active photocatalyst and the usage of solar radiation are mandatory steps. Thus, Fe3O4–SiO2–TiO2 was synthesized, and its performance was evaluated using simulated solar radiation and methylene blue as a model pollutant. Under optimal conditions, 86% degradation was attained in 1 h. These results were compared to recent published data, and the better performance can be attributed to both the operational conditions selection and the higher photocatalyst activity. Indeed, Fe3O4–SiO2–TiO2 was physico-chemically characterized with techniques such as XRD, N2 isotherms, spectrophotometry, FTIR, electrochemical assays and TEM.

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