Carbon Monoxide Photoproduction from Particles and Solutes in the Delaware Estuary under Contrasting Hydrological Conditions.
Full-spectrum, ultraviolet (UV), and visible broadband apparent quantum yields (AQYs) for carbon monoxide (CO) photoproduction from chromophoric dissolved organic matter (CDOM) and particulate organic matter (POM) were determined in the Delaware Estuary in two hydrologically contrasting seasons in 2012: an unusually low flow in August and a storm-driven high flow in November. Average AQYs for CDOM and POM in November were 10 and 16 times the corresponding AQYs in August. Maximum AQYs in November occurred in a midestuary particle absorption maximum zone. Although POM AQYs were generally smaller than CDOM AQYs, the ratio of the former to the latter increased substantially from the UV to the visible. In both seasons, UV solar radiation was the primary driver for CO photoproduction from CDOM whereas visible light was the principal contributor to POM-based CO photoproduction. CDOM dominated CO photoproduction in the uppermost water layer while POM prevailed at deeper depths. On a depth-integrated basis, the Delaware Estuary shifted from a CDOM-dominated system in August to a POM-dominated system in November with respect to CO photoproduction. This study reveals that flood events may enhance photochemical cycling of terrigenous organic matter and switch the primary photochemical driver from CDOM to POM.
Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski , 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada.|College of Marine and Environmental Sciences, Tianjin University of Science and Technology , 29 13th Avenue, TEDA, Tianjin 300457, P.R. China.
Guisheng
G
Song
Department of Chemistry, State University of New York, College of Environmental Science and Forestry , 1 Forestry Drive, Syracuse, New York 13210, United States.
John D
JD
Richardson
Department of Chemistry, State University of New York, College of Environmental Science and Forestry , 1 Forestry Drive, Syracuse, New York 13210, United States.
James P
JP
Werner
Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski , 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada.
Huixiang
H
Xie
Department of Chemistry, State University of New York, College of Environmental Science and Forestry , 1 Forestry Drive, Syracuse, New York 13210, United States.
David J
DJ
Kieber
D002248:Carbon Monoxide / Q000032:analysis / Q000737:chemistry*; D003691:Delaware; D004784:Environmental Monitoring / Q000379:methods; D063366:Estuaries; D055868:Floods; D062070:Hydrology / Q000379:methods; D008027:Light; D055668:Photochemical Processes; D012621:Seasons; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D014874:Water Pollutants, Chemical; D014867:Water; D002248:Carbon Monoxide