分解
沉积物
环境化学
缺氧水域
化学
磷
碎片
沉积物-水界面
磷酸盐
地质学
有机化学
海洋学
古生物学
作者
Wenqiang Zhang,Xiaolei Zhu,Xin Jin,Xin Meng,Wenzhong Tang,Baoqing Shan
标识
DOI:10.1016/j.scitotenv.2017.01.103
摘要
The processes and mechanisms through which phosphorus (P) is released from sediment and organic P is transformed, induced by the decomposition of plant (duckweed (Lemma minor L.)) debris, were studied experimentally. In the simulation experiments, the dissolved oxygen concentration, pH, and oxidation–reduction potential at the water–sediment interface first decreased rapidly. The lowest oxidation–reduction potential reached was 225.4 mV, and the solution became weakly acidic (pH 5.14) and anoxic (dissolved oxygen concentration 0.17 mg·L− 1). The dissolved oxygen concentration, pH, and oxidation–reduction potential then became stable. The soluble reactive P, total dissolved P, and total P concentrations in the overlying water all increased rapidly because of the particulate P and dissolved organic P released as the plant debris decomposed. 31P NMR analysis of the solution showed that orthophosphate monoesters were the main organic P compounds in the sediment. The orthophosphate monoester and orthophosphate diester concentrations were higher during the first 7 d of the experiment (at 71.2 and 15.3 mg·kg− 1, respectively) than later (60.8 and 14.6 mg·kg− 1, respectively). The decomposition of the duckweed could have mineralized the orthophosphate monoesters and orthophosphate diesters to give orthophosphate. The results indicated that the decomposition of aquatic plant debris is a key factor in the release of P from sediment even when external P is excluded. It is therefore necessary to remove plant debris from freshwater ecosystems to control the release of P from plant debris and sediment.
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