Carbon Monoxide Photoproduction: Implications for Photoreactivity of Arctic Permafrost-Derived Soil Dissolved Organic Matter

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• 作者：Jun Hong ; Huixiang Xie ; Laodong Guo ; Guisheng Song
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：August 19, 2014
• 年：2014
• 卷：48
• 期：16
• 页码：9113-9121
• 全文大小：407K
• ISSN：1520-5851

文摘

Apparent quantum yields of carbon monoxide (CO) photoproduction (AQY_CO) for permafrost-derived soil dissolved organic matter (SDOM) from the Yukon River Basin and Alaska coast were determined to examine the dependences of AQY_CO on temperature, ionic strength, pH, and SDOM concentration. SDOM from different locations and soil depths all exhibited similar AQY_CO spectra irrespective of soil age. AQY_CO increased by 68% for a 20 掳C warming, decreased by 25% from ionic strength 0 to 0.7 mol L^鈥?, and dropped by 25鈥?8% from pH 4 to 8. These effects combined together could reduce AQY_CO by up to 72% when SDOM transits from terrestrial environemnts to open-ocean conditions during summer in the Arctic. A Michaelis鈥揗enten kinetics characterized the influence of SDOM dilution on AQY_CO with a very low substrate half-saturation concentration. Generalized global-scale relationships between AQY_CO and salinity and absorbance demostrate that the CO-based photoreactivity of ancient permaforst SDOM is comparable to that of modern riverine DOM and that the effects of the physicochemical variables revealed here alone could account for the seaward decline of AQY_CO observed in diverse estuarine and coastal water bodies.