title: Benthic flux of dissolved organic matter from lake sediment at different redox conditions and the possible effects of biogeochemical processes.
abstract: The benthic fluxes of dissolved organic carbon (DOC), chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) were studied for the sediment from an artificial lake, based on laboratory benthic chamber experiments. Conservative estimates for the benthic flux of DOC were 71 ± 142 and 51 ± 101 mg m(-2) day(-1) at hypoxic and oxic conditions, respectively. Two humic-like (C1 and C2), one tryptophan-like (C3), and one microbial humic-like (C4) components were identified from the samples using fluorescence excitation emission matrices and parallel factor analysis (EEM-PARAFAC). During the incubation period, C3 was removed while C4 was accumulated in the overlying water with no significant difference in the trends between the redox conditions. The humification index (HIX) increased with time. The combined results for C3, C4 and HIX suggested that microbial transformation may be an important process affecting the flux behaviors of DOM. In contrast, the overall accumulations of CDOM, C1, and C2 in the overlying water occurred only for the hypoxic condition, which was possibly explained by their enhanced photo-degradation and sorption to redox-sensitive minerals under the oxic condition. Our study demonstrated significant benthic flux of DOM in lake sediment and also the possible involvement of biogeochemical transformation in the processes, providing insight into carbon cycling in inland waters.
authors.affiliation: Department of Environment & Energy, Sejong University, Seoul 143-747, South Korea.
authors.forename: Liyang
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Environmental Science & Engineering, Ewha Womans University, Seoul 120-750, South Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Department of Environment & Energy, Sejong University, Seoul 143-747, South Korea. Electronic address: jinhur@sejong.edu.
authors.forename: Jin
authors.initials: J
authors.lastname: Hur
mesh_terms: D057486:Carbon Cycle; D019015:Geologic Sediments / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis*; D060106:Lakes / Q000737:chemistry*; D010084:Oxidation-Reduction; D056910:Republic of Korea
chemical_list: D006812:Humic Substances
keywords: Benthic flux; Dissolved organic carbon; EEM-PARAFAC; Lake; Sediment