不同预处理干燥方法对海洋沉积物磷形态提取的影响

以采集于茅尾海五个典型区域表层沉积物为例，对比了冷冻干燥，恒温烘干和自然风干等三种预处理干燥方法对海洋沉积物磷形态提取及其生物有效性评价的影响。结果表明:长时间的风干前处理过程促进了沉积物磷化合物微生物降解转化为无机磷（IP），导致风干样品的IP和总磷（TP）浓度最高。不同预处理干燥方法对沉积物各形态磷的影响程度不同，冻干样品中有机磷（OP）浓度最高，烘干样品中可交换态磷（Ex-P）浓度最高，风干样品中铁结合态磷（Fe-P）浓度最高。由于自生磷灰石磷（Ca-P）和原生碎屑磷（De-P）化学性质稳定，提取浓度随干燥方法的变化趋势不明显。相比其他两种方法，冷冻干燥能较为真实地反映海洋沉积物不同形态磷的组成特征，是比较理想的样品干燥方法。相关性分析表明，除了Ca-P之外，不同预处理干燥方法对沉积物中Ex-P、Fe-P、De-P和OP提取的影响是整体性的，并非是由个别样品的变化所导致。风干样品中生物有效磷（BAP）浓度高于其他两种预处理方法，但单因素方差分析显示这三种预处理干燥方法对评价茅尾海潮间带表层沉积物潜在的BAP无显著性差异。

Effects of different pretreatment drying method on sequentially extracted phosphorus forms in marine sediments

The effects of three different pretreatment drying methods (vacuum freeze-drying, oven-drying and air-drying) on the analysis of phosphorus (P) species and their bioavailability were investigated in five typical surface sediments from the Maowei sea in the northern Beibu Gulf.The long-term pretreatment process of air-drying promoted the microbial degradation and transformation of sedimentary P compounds into inorganic P (IP), resulting in the highest concentrations of IP and total P (TP).The highest levels of organic P (OP) were recorded in freeze-drying samples.Among different IP species, the highest concentrations of exchangeable P (Ex-P) and Fe-bound P (Fe-P) were found in oven-drying and air-drying samples, respectively.The variation trend of the extraction concentration of authigenic apatite P (Ca-P) and detrital P (De-P) using different pretreatment drying methods was not significant due to their stable chemical properties.Compared with the other two methods, freeze-drying could reflect the actual composition characteristics of different P forms in marine sediments, and is an ideal method for sample drying.Thus, this pretreatment seems to be the best drying method.Correlation analysis indicated that, in addition to Ca-P, changes of individual samples did not influence the analytical integrity of Ex-P, Fe-P, De-P and OP in extracted solutions from different pretreatment drying methods.The concentrations of bioavailable P (BAP) in the air-drying samples were higher than those of vacuum freeze-drying and oven-drying but, the single factor analysis of variance showed no significant differences on the evaluation potential BAP in surface sediments of the Maowei sea based on the three pretreatment drying methods.