Singlet oxygen in surface waters — Part II: Quantum yields of its production by some natural humic materials as a function of wavelength

Haag, Werner R.; ́, Ju ̈rg Hoigne; Gassman, Ernst; Braun, André M.

doi:10.1016/0045-6535(84)90200-5

Cited by 107 publications

(120 citation statements)

References 8 publications

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“…Previously reported f values were obtained for so natural waters using 2,5-dimethylfuran or furfuryl alcohol as a singlet oxygen scavenger, and fall in the Ž range 0.004-0.030 Zepp et al, 1977;Haag et al, . 1984;Zepp et al, 1985;Frimmel et al, 1987 .…”

Section: Photophysical Characteristicsmentioning

confidence: 99%

Photogeneration of singlet oxygen and free radicals in dissolved organic matter isolated from the Mississippi and Atchafalaya River plumes

et al. 2000

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Ž. The photoreactivity to UV light of ultrafiltered dissolved organic matter DOM collected during cruises along salinity transects in the Mississippi and Atchafalaya River plumes was examined by measuring photogenerated free radicals and Ž 1 . singlet molecular oxygen O photosensitization. Singlet oxygen was detected by its infrared phosphorescence at 1270 nm 2 using both steady-state and time-resolved techniques. The 1 O quantum yields were corrected for self-quenching of 1 O by 2 2 Ž . the DOM substrates. Photogenerated free radicals were monitored by electron paramagnetic resonance EPR . Two size fractions of the dissolved organic matter were examined: material retained with a 3 kDa cut-off filter and material retained with a 1 kDa cut-off filter. The highest 1 O quantum yields were found in the lower molecular mass material. There was 2 little change in the 1 O quantum yields with increasing salinity, indicating that the photosensitizing ability of the estuarine 2 DOM does not decrease as terrestrial DOM is transported to sea and mixes with marine DOM. In contrast to 1 O formation, 2 the steady-state levels of photoproduced free radicals did not significantly differ between high and low molecular mass DOM, and the levels were substantially higher in riverine DOM than along plume salinity transects. This rapid transition in free radical level suggests that terrestrially-derived DOM experiences significant changes in this aspect of its photoreactivity Ž . in low -10 ppt salinity waters. Published by Elsevier Science B.V.

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Section: Photophysical Characteristicsmentioning

confidence: 99%

Photogeneration of singlet oxygen and free radicals in dissolved organic matter isolated from the Mississippi and Atchafalaya River plumes

et al. 2000

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“…A number of naturally occurring pigments are known to act as photosensitizing dyes, producing singlet oxygen when submitted to light above 500 nm (Larson 1978), and quantum yields of 1 O 2 production by humic materials have been published by Haag et al (1984). Chl a, for example has a pronounced second absorption maximum between 600 and 700 nm.…”

Section: Laboratory Studies On the Wavelength Dependence Of Lightindumentioning

confidence: 99%

Light‐induced redox cycling of iron in circumneutral lakes

Emmenegger

Schönenberger

Sigg

et al. 2001

Limnology & Oceanography

141

127

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The light-induced redox cycling of Fe II /Fe III was studied both in laboratory experiments and in the field in two circumneutral Swiss lakes: Greifensee, a eutrophic, natural water body, and Melchsee, an oligotrophic, artificial mountain lake. To determine Fe II at the nanomolar level, an automated flow-injection analysis system was used. Irradiation by simulated sunlight leads to pH dependent (pH 6.9-9. II at the surface of both lakes is produced by light-induced processes, whereas the deeper Fe II maxima at depths with maximal chlorophyll a concentrations are probably due to a combination of biologically and photochemically induced processes.

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“…The bulk (~90%) of sunlight absorbed by DOM is converted directly to heat within a few nanoseconds (Milne et aI., 1987). A certain fraction of the initially-formed excited state 1 DOM undergoes intersystem crossing to the longer-lived 3DOM state (Zepp et al, 1985;Haag et al, 1984b). Essentially al of the 3DOM is quenched by oxygen (Zepp et aI., 1985); most of these quenching acts probably yield 102, which, in turn, mostly decays by heating the water.…”

Section: Uv Effects On Homogeneous Chemical Processesmentioning

confidence: 99%

“…), hydroxyl radicals (HO. ), solvated electrons (e;;q), and superoxide ion (02') (Faust and Hoigné, 1987;Fischer et ai., 1985;Hoigné, 1985, 1986;Haag et al, 1984aHaag et al, , 1984bMil et ai., 1980;Petasne and Zika, 1987;Russi et al, 1982;Zepp et al, 1985Zepp et al, , 1987aZepp et al, , 1987b. The primary reason for their interest is that they can effect transformations of many natural and man-made compounds.…”

Section: Uv Effects On Homogeneous Chemical Processesmentioning

confidence: 99%

“…First, because formation rates are proportional to light intensity, an increased light flux wil increase production. Second, because the quantum yield of formation increases with decreasing wavelength (Zepp et al, 1985;Haag et al, 1984b;Cooper et al, 1988), the effciency of production wil be increased. Thirdly, because DOM absorbs light more strongly the lower the wavelength, sunlight wil be absorbed in a shorter path and the oxidants wil be concentrated closer to the surface.…”

Section: Uv Effects On Homogeneous Chemical Processesmentioning

confidence: 99%

See 1 more Smart Citation

Effects of solar ultraviolet radiation on biogeochemical dynamics in aquatic environments : report of a workshop, Marine Biological Laboratory, Woods Hole, Massachusetts, October 23-26, 1989

Blough¹,

Zepp²

1990

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Singlet oxygen in surface waters — Part II: Quantum yields of its production by some natural humic materials as a function of wavelength

Cited by 107 publications

References 8 publications

Photogeneration of singlet oxygen and free radicals in dissolved organic matter isolated from the Mississippi and Atchafalaya River plumes

Photogeneration of singlet oxygen and free radicals in dissolved organic matter isolated from the Mississippi and Atchafalaya River plumes

Light‐induced redox cycling of iron in circumneutral lakes

Effects of solar ultraviolet radiation on biogeochemical dynamics in aquatic environments : report of a workshop, Marine Biological Laboratory, Woods Hole, Massachusetts, October 23-26, 1989

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