湖泊水体溶解氧水平对内源磷释放的影响

Influence of dissolved oxygen levels in lakes on endogenous phosphorus release

以江苏省里下河地区的大纵湖为研究对象,通过室内原位培养法,在3种不同溶解氧水平下(自然状态、好氧状态和厌氧状态)对湖底底泥原位沉积柱进行了连续16 d的室内培养,研究浅水湖泊溶解氧水平对上覆水体可溶性磷酸盐(SRP)释放的影响。结果发现:在不同溶解氧条件下,上覆水体SRP含量有显著差异,厌氧条件下上覆水体SRP平均含量比自然条件下高7倍左右,而好氧条件下上覆水体则比自然条件下低了近80%。由此说明,与自然状态相比,厌氧条件能显著促进内源磷的释放,而好氧条件则会抑制这一过程,甚至出现磷吸附现象,好氧条件能降低上覆水中磷的含量,改善湖泊富营养化状况。

Taking Dazong Lake in Lixiahe area of Jiangsu Province as the research object, the in - situ sediment columns of Dazong lake were cultured for 16 days under three different levels of dissolved oxygen （ natural state, aerobic and anaerobic state） , so as to study the influence of different dissolved oxygen levels on the soluble phosphate （SRP） releasing in the overlying water. The research showed that under different dissolved oxygen concentrations, the content of SRP in the overlying water is strikingly different. Under the anaerobic conditions, the average SRP content in the overlying water is about 7 times higher than that under natural conditions, and under aerobic condition, the average SRP content reduces nearly 80% comparing with the nat- ural condition. Therefore, the anaerobic conditions can significantly promote the release of internal phosphorus compared with the nature state, while the aerobic conditions can inhibit this process, even the phosphorus adsorption phenomenon occurs, which shows that the aerobic condition can reduce the phosphorus content in the overlying water and mitigate the eutrophication of lakes.