山美水库表层沉积物黑碳分布特征及其对磷形态的影响

摘要

对亚热带水库福建山美水库表层沉积物黑碳的时空分布特征及其对不同形态磷的影响进行了研究.结果表明,山美水库表层沉积物黑碳(BC)含量为2.44~5.28g/kg,与国外研究水库水平相当,显著高于国内外海岸带沉积物黑碳水平.黑碳整体分布特征为：丰水期>枯水期,入库区>库尾>近坝区>库中.沉积物中黑碳与总有机碳呈现显著的正相关性,与沉积物粒径分布无明显相关关系.黑碳与有机碳比值平均为24.95%,表明黑碳来源复杂,是陆源生物质燃烧和化石燃料燃烧的共同结果.黑碳与有机磷和铁铝结合态磷这两种易释放磷之间显著相关,其对有机磷和铁铝结合态磷具有一定的吸附固定作用,这种吸附作用可能对沉积物内源磷释放具有一定的抑制效应.%Temporal and spatial distributions of black carbon in surface sediments of a subtropical reservoir were investigated and the effects of black carbon on different phosphorous species were explored as a case study of Shanmei Reservoir in Fujian Province. The mass concentrations of black carbon (BC) in surface sediments were 2.44to 5.28g/kg in Shanmei Reservoir, which higher than those in coastal sediment. It was consistent with the results from the studies on reservoirs abroad. Overall, the BC concentrations were higher in wet season than in dry season. There were highest BC concentrations at the inlet area followed in order by those at the tail area, the dam nearby area and the middle area of the reservoir. The concentrations of black carbon had a significantly positive correlation with the concentrations of total organic carbon in the sediments, but no correlation with particle size. The ratio of black carbon to organic carbon was averaged as 24.95%, which indicated that the BC source was complex, and it commonly originated from terrestrial biomass combustion and combustion of fossil fuels. Black carbon and two active species of phosphorus (organic phosphorus and iron/aluminum bound phosphorus) were correlated significantly. Black carbon had a certain fixation to absorb these phosphorus forms, which would cause certain inhibition on the release of sediment phosphorus.