This study evaluated the water quality above the marine sediment by inputting oxygen releasing compound (ORC) processed from calcined oyster shells. Presumed vital parameters such as DO, pH, ORP, chlorophyll-a and classified phosphorous compounds were monitored for 20 d. ORP decreased with time in the control bed, while it increased to a positive value as a result of the ORC effect. DO kept showing a relatively high concentration in ORC treated column. We observed an increase of chlorophyll-a and a decrease of dissolved inorganic phosphate (DIP) simultaneously, which meant the released inorganic phosphorus would convert to an organic form in the overlying water. TP rises were the lowest in the ORC column (79%), meanwhile in the control column those went up to 0.304 mg/L (85%). Also, phosphorus fractions were measured in the sediment: Fe-P decreased in control while Fe-P and Ca-P soared greatly in the ORC column. This implies that in more oxidized environment inorganic phosphate bound to Ca-species would be eliminated as solidified precipitates in the sediment pore water, and it consequently suppressed the release of phosphates to the overlying water. The results indicate that the release of phosphorus and resulting eutrophication could be effectively controlled via the local environment improved by calcined ORC.

中文翻译：

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牡蛎壳粉过氧化钙对大洋沉积物中磷化合物的控制作用

本研究通过输入由煅烧牡蛎壳加工而成的释氧化合物 (ORC) 来评估海洋沉积物上方的水质。假定的重要参数如 DO、pH、ORP、叶绿素-a 和分类的磷化合物被监测 20 天。ORP 在对照床中随着时间的推移而下降，而由于 ORC 的影响，它增加到正值。在 ORC 处理的柱子中，DO 一直显示出相对较高的浓度。我们同时观察到叶绿素-a 的增加和溶解的无机磷酸盐 (DIP) 的减少，这意味着释放的无机磷将在上覆水中转化为有机形式。ORC 柱中的 TP 上升最低 (79%)，同时在对照柱中上升到 0.304 mg/L (85%)。此外，还测量了沉积物中的磷含量：在ORC柱中Fe-P和Ca-P在对照中下降，而Fe-P和Ca-P大幅飙升。这意味着在更氧化的环境中，与 Ca 物种结合的无机磷酸盐将作为沉积物孔隙水中的固化沉淀物被消除，从而抑制了磷酸盐向上覆水中的释放。结果表明，通过煅烧ORC改善局部环境可以有效控制磷的释放和由此产生的富营养化。