西湖底泥不同供氧条件下有机质降解及CO_2与CH_4释放速率的模拟研究

Simulated studies on degradation of organic matter and release of CO 2 and CH 4 in sediment from the west lake under various oxygen supply conditions

采用密闭培养实验装置于室温（２５℃左右）及ｐＨ为７５条件下，对西湖底泥中有机质完全降解及转化为ＣＯ２和ＣＨ４的速率进行了模拟研究．结果表明，在西湖湖水现有供氧水平（５０—８６ｍｇ（Ｏ２）／Ｌ）条件下，底泥中有机质完全降解的速率最为缓慢，培养期间（４２天）平均只有０７２ｍｇ（Ｃ）／（ｋｇ·ｄ）．当湖水供氧水平进一步上升（８６→１２０→１６０ｍｇ（Ｏ２）／Ｌ），ＣＯ２释放速率增加，最大值可达到８７ｍｇ（Ｃ）／（ｋｇ·周）；当湖水供氧水平下降（８６→０ｍｇ（Ｏ２）／Ｌ），ＣＨ４释放速率加快，最大值可达到４６ｍｇ（Ｃ）／（ｋｇ·周）．

Rates of complete degradation of organic matter in sediment from the West Lake and its changes into CO 2 and CH 4 were simulatively studied with the closed culture experimental installation. Under the current oxygen supply level(8.6 mg(O 2)/L) of the West Lake water, the rate of complete degradation of organic matter in the sediment was slowest. The average degradation rate was only 0.72 mg(C)·kg -1 ·d -1 during the whole culture time. The release rate of CO 2 increased with the increase(8.6→12 0→16.0 mg (O 2)/L) in oxygen supply levels of the West Lake water. The maximum release rate of CO 2 was up to 8.7 mg (C)·kg -1 ·week -1 under the experimental conditions. The release rate of CH 4 also speeded up when dissolved oxygen in water decreased. The maximum release rate of CH 4 was up to 4.6 mg (C)·kg -1 ·week -1 under the airtight culture condition.