预处理及保存方法对浮游动物碳、氮稳定同位素比值的影响

研究了不同预处理及保存方法对浮游动物碳、氮稳定同位素比值的影响.结果表明:未清养的舌状叶镖水蚤PhyHodiaptomus tunguidus与清养3h的相比δ¹³C和δ¹⁵N的差异均不显著,但肠道内含物造成了重复样品间的较大偏差;去除脂肪后的舌状叶镖水蚤δ¹³C和δ¹⁵N均显著升高;经甲醇保存后,舌状叶镖水蚤和奥氏秀体溞Diaphanosoma orghidani transamurensis的δ¹³C均有所升高,但不显著;经乙醇保存后,舌状叶镖水蚤δ¹³C显著升高,而奥氏秀体溞的δ¹³C也有所升高但不显著;经过甲醛保存后,舌状叶镖水蚤和奥氏秀体溞的δ¹³C降低,但不显著;冰冻保存使奥氏秀体溞的δ¹³C显著降低,而使舌状叶镖水蚤的δ¹³C也有所降低但不显著.四种保存方法对舌状叶镖水蚤和奥氏秀体溞的δ¹⁵N都没有显著影响.在进行不同研究间的比较时,必须考虑样品保存与处理方法造成的差异.同时,食物网结构的稳定同位素研究有待建立统一的样品保存与处理方法.

Effect of pretreatment and preservation procedures on carbon and nitrogen stable isotope ratios of zooplankton

The effect of pretreatment.and preservation procedures on carbon and nitrogen stable isotope ratios of zooplankton Phyllodiaptomus tunguidus and Diaphanosoma orghidani transamurensis was studied.The results showed that gut contents in P.tunguidus led to a significant deviation in the values of replicates of both δ^I3C and δ^I5N.Lipid extraction resulted in a significant enrichment in δ^I3C and δ^I3N in P.tunguidus.Methanol and ethanol preserved animals showed higher δ^I3C values,while the frozen and formalin-preserved animals resulted in lower δ^I3C values.δ^I5N of two species was affected slightly,but not significantly,by four different preservations in this study.The results suggest that the variation from different treatments must be considered when making cross-study comparisons.Standard protocols for sample preparation and preservation are needed for the study of foodweb structure via stable isotope analysis.