有机质对三峡库区消落区沉积物磷释放的影响

摘要

Taking the sediments in the fluctuating zone of the Fengdu section in the Three Gorges Reservoir Area as the study object, phosphorous forms in the sediments and adsorption isotherm curves of phosphorous to mineral sediments and light fraction organic matter-removed sediments were analyzed. This study reveals the correlation between forms and release laws of phosphorous and organic matter. The results show: total phosphorous (TP) content, organic phosphorous content and active phosphorous content in background soils are higher than their corresponding contents in sediments in the fluctuating zone. In addition, the very first submersion poses more potential risk of phosphorous release. The exposing state in summer is conducive to accumulation of organic matter and organic phosphorous in the sediments. Decomposition of organic matter boosts the release of phosphorous.Moreover, organic matter content in sediments show a significant positive correlation with organic phosphorous content, while a negative correlation with inorganic phosphorous content.%以三峡库区丰都消落区沉积物为研究对象,通过分析沉积物中磷的赋存形态,以及去除轻组有机质沉积物和沉积物矿物质对磷的吸附等温曲线,揭示了磷的赋存形态及释放与有机质的关系.结果表明:消落区本底土壤较沉积物w(总磷),w(有机磷)及w(活性磷)更高,首次覆水时更具潜在释磷风险,夏季出露期有利于沉积物有机质和有机磷积累,沉积物有机质矿化分解对磷释放起促进作用,沉积物中w(有机质)与w(有机磷)呈显著正相关,与w(无机磷)呈负相关.