Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physical Sciences and Mathematics
Rate And Apparent Quantum Yield Of Photodissolution, Meg Estapa, Lawrence M. Mayer, Emmanuel Boss
Rate And Apparent Quantum Yield Of Photodissolution, Meg Estapa, Lawrence M. Mayer, Emmanuel Boss
Geosciences
We quantified rates of photochemical dissolution (photodissolution) of organic carbon in coastal Louisiana suspended sediments, conducting experiments under well-defined conditions of irradiance and temperature. Optical properties of the suspended sediments were characterized and used in a radiative transfer model to compute irradiances within turbid suspensions. Photodissolution rate increased with temperature (T), with activation energy of 32 ± 7 kJ mol−1, which implicates indirect (non-photochemical) steps in the net reaction. In most samples, dissolved organic carbon (DOC) concentration increased approximately linearly with time over the first 4 h of irradiation under broadband simulated sunlight, after higher rates in the initial hour …
Role Of Iron And Organic Carbon In Mass-Specific Light Absorption By Particulate Matter From Louisiana Coastal Waters, Meg Estapa, Emmanuel E. Boss, Mayer M. Lawrence, Roesler S. Collin
Role Of Iron And Organic Carbon In Mass-Specific Light Absorption By Particulate Matter From Louisiana Coastal Waters, Meg Estapa, Emmanuel E. Boss, Mayer M. Lawrence, Roesler S. Collin
Geosciences
We investigated the influences of organic content and mineralogical composition on light absorption by mostly mineral suspended particles in aquatic and coastal marine systems. Mass-specific absorption spectra of suspended particles and surface sediments from coastal Louisiana and the lower Mississippi and Atchafalaya rivers were measured with a centered sample-mount integrating sphere and analyzed in conjunction with organic carbon (OC), hydrochloric acid– (HCl-) extractable iron, and dithionite-extractable iron contents. Compositions and absorption properties were comparable to published values for similar particles. Dithionite-extractable iron was strongly correlated with absorption at ultraviolet (UV) and blue wavelengths, while OC and HCl-extractable iron were weakly …