深海小型底栖生物Ludox离心分选方法的改进研究

An improved method for separating meiofauna from deep-sea sediments using colloidal silica Ludox@HS-40

使用Ludox@HS-40作为介质,对一系列深海小型底栖生物进行了离心分离实验,对小型底栖生物分选率在不同密度和离心速度条件下的双因素方差进行了分析,并确定了该种试剂的最佳密度和最佳的离心速度。结果表明：Ludox@HS-40介质密度和离心速度对小型底栖生物的分选率影响显著,但密度和离心速度间交互效应对分选率的影响却并不显著,Ludox@HS-40介质的最佳密度应大于等于1.18 g/mL,最佳离心速度为1 800-2 000 r/min,此时小型底栖生物分选率将大于等于97%。

Separating meiofauna from marine sediment samples is a key step in the studies of the taxonomy and ecology of meiofauna,and its accuracy can affect the reliability of the following studies.At the present time,there are a variety of means in separating meiofauna,but the ways applying to separating deep-sea meiofauna are few.It is appreciated and widely applicable in separating deep-sea meiofauna by the way of Ludox centrifugation,but there are a great many argues on the specific density and centrifugal speed of Ludox as the media in the studies,especially in the separating deep-sea meiofauna.The optimal specific density and centrifugal speed of Ludox@HS-40 as the media was studied by the way of Ludox centrifugation to extract meiofaunal organisms from deep-sea sediments,which improved the application of Ludox centrifugation and promoted the accuracy and efficiency in sorting deep-sea sediment samples.Meiofaunal samples used in this experiment were collected with a multiple corer which came from polymetallic nodule areas in the East Pacific Ocean and the depth was more than 4 000 m.The specific density of Ludox were setting to 1.12,1.15,1.18,1.23,1.30 g/mL separately,and the centrifugal speed were transferred to 1 000,1 500,1 700,1 800,2 500 r/min respectively,then each group had 5 parallel samples to take exercises.The formula for calculating extraction efficiency is E（%）=（N1/（N1＋N2））×100%,in which E represents extraction efficiency,N1 represents the number of meiofauna in the supernatant,and N2 represents the remaining meiofauna in the sediment samples after centrifugation.Finally the results we acquired proceed the multiple factor variance analysis by SPSS 16.0 software.Results showed that the specific density of Ludox@HS-40 proved significant effect on the extraction efficiency of benthic meiofauna,however centrifugal speed had no significant effect,and there were no interaction effect exists between specific density and centrifugal speed.The mean extraction efficiency of benthic meiofauna was rising as the increasing of the specific density of Ludox@（DuPont） HS-40,and when the specific density of Ludox@HS-40 ≥1.18,the extraction efficiency of meiofauna was ≥97%.When the centrifugal speed was less than 1 700 r/min,the supernatant had a high sediment charge,and when increasing the speed to 2 000 r/min,the structure of some meiofauna were damaged,so the optimal centrifugal speed was 1 800~2 000 r/min obtained in this experiment.