title: [Effects of light irradiation on phosphorous releases from typical submerged soils of water-level fluctuation zones of Three Gorges Reservoirs areas].
abstract: For understanding the impact of light irradiation on the phosphorus (P) releases from soil-water interface, two types of typical soils sampled from water-level fluctuation zones of Three Gorges Reservoir areas were selected as research objectives, and simulated light irradiation experiment in lab was conducted for unveiling the underlying mechanisms of P releases from submerged soils in the presence of light irradiation. The results showed that light irradiation could inhibit P releases from submerged soils by a certain degree. Under light condition, total P (TP) concentrations in underlying water of submerged purple soil ranged from 0.018 to 0.033 mg x L(-1), as compared to the range of 0.02-0.057 mg x L(-1) in darkness treatment. Additionally, for gray-brown purple soil, TP was in a range of 0.028-0.045 mg x L(-1) when light irradiated, but in the range of 0.04-0. 084 mg x L(-1) under darkness condition. Meanwhile, changes of iron oxides in soils due to light irradiation were possibly to be the important reason to explain the inhabitation of light irradiation on P releases. Moreover, light irradiation resulted in decreasing saturation degree of iron oxides in soils, which further inhibited the iron reduction and production of amorphous iron, further enhanced the underlying mechanisms of decreasing P releases in presence of light irradiation. Further, CO2 and CH4 could reflect decomposition of soil organic carbon (SOC) in submerged condition. Light irradiation significantly decreased SOC transformation into carbon gases. Stimulating consumption of inorganic electron acceptors in submerged soils could also be used to explain the changes of iron oxides under light irradiation condition. Thus, inhabitation of light irradiation on P releases from submerged soils obviously related with iron minerals reduction and decomposition of organic matter in soils.
authors.forename: Nian
authors.initials: N
authors.lastname: Guo
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Shi-Qiang
authors.initials: SQ
authors.lastname: Wei
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Yan
authors.forename: Jian
authors.initials: J
authors.lastname: Liang
authors.forename: Song
authors.initials: S
authors.lastname: Lu
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
mesh_terms: D002681:China; D008027:Light; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D012987:Soil; D014867:Water; D010758:Phosphorus