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Author |
Beine Harry, Anastasio Cort, Domine Florent, Douglas Thomas, Barret Manuel, France James, King Martin, Hall Sam, Ullmann Kirk, |
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Title |
Soluble chromophores in marine snow, seawater, sea ice and frost flowers near Barrow, Alaska
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Type |
Journal Article |
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Year  |
2012 |
Publication |
J. Geophys. Res. |
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Volume |
117 |
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D00R15- |
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Keywords |
OASIS, chromophores, colored dissolved organic matter (CDOM), frost flowers, light absorption, marine, 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties, 0322 Atmospheric Composition and Structure: Constituent sources and sinks, 0736 Cryosphere: Snow (1827, 1863), 0750 Cryosphere: Sea ice (4540), 4807 Oceanography: Biological and Chemical: Chemical speciation and complexation, |
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Abstract |
We measured light absorption in 42 marine snow, sea ice, seawater, brine, and frost flower samples collected during the OASIS field campaign between February 27 and April 15, 2009. Samples represented multiple sites between landfast ice and open pack ice in coastal areas approximately 5 km west of Barrow, Alaska. The chromophores that are most commonly measured in snow, H2O2, NO3-, and NO2-, on average account for less than 1% of sunlight absorption in our samples. Instead, light absorption is dominated by unidentified “residual” species, likely organic compounds. Light absorption coefficients for the frost flowers on first-year sea ice are, on average, 40 times larger than values for terrestrial snow samples at Barrow, suggesting very large rates of photochemical reactions in frost flowers. For our marine samples the calculated rates of sunlight absorption and OH production from known chromophores are (0.1–1.4) 1014 (photons cm-3 s-1) and (5–70) 10-12 (mol L-1 s-1), respectively. Our residual spectra are similar to spectra of marine chromophoric dissolved organic matter (CDOM), suggesting that CDOM is the dominant chromophore in our samples. Based on our light absorption measurements we estimate dissolved organic carbon (DOC) concentrations in Barrow seawater and frost flowers as approximately 130 and 360 μM C, respectively. We expect that CDOM is a major source of OH in our marine samples, and it is likely to have other significant photochemistry as well.
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1017 |
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AGU |
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ISSN |
0148-0227 |
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Approved |
yes |
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Call Number |
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Serial |
989 |
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