南海鸢乌贼耳石微量元素差异性分析

Difference analysis of trace elements in statolith of Sthenoteuthis oualaniensis in South China Sea

文章通过激光剥蚀电感耦合等离子体质谱法(laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS)测量南海鸢乌贼(Sthenoteuthis oualaniensis)耳石微量元素浓度,分析鸢乌贼耳石微量元素组成及与钙(Ca)元素比值的变化,探讨其存在的差异和与栖息环境之间的关系。结果表明,鸢乌贼耳石主要微量元素为Ca、锶(Sr)、钠(Na)、铁(Fe)、钡(Ba)、锰(Mn)。方差分析表明,鸢乌贼中型群和微型群及其性别间耳石微量元素浓度差异不显著(P>0.05)。除Fe/Ca外,不同耳石区域微量元素浓度与Ca比值存在显著性差异(P<0.01)。核心区Sr/Ca最高,随后逐渐降低,不同产卵群体和地理区域耳石Sr/Ca无显著差异(P>0.05)。幼体期Sr/Ca与温度呈正相关性,与盐度呈负相关性,可以作为良好的温度指标。Na/Ca先增大后减小,暗区最高,核心区和后核心区Na/Ca在不同产卵群体间差异显著(P<0.01)。Mn/Ca和Ba/Ca先减小后增大,暗区最低,随后分别在边缘区和外围区增大。成体期耳石Ba/Ca与盐度呈正相关,可以作为垂直移动的指标。Fe/Ca在不同产卵群体和地理区域中差异显著(P<0.01)。分析认为,Na/Ca和Fe/Ca较为适合研究南海鸢乌贼不同群体的划分,Sr/Ca和Ba/Ca可用于推测鸢乌贼的栖息环境。

Laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)was used to measure the concentration of trace elements in the otolith of the South China Sea squid(Sthenoteuthis oualaniensis).The composition of trace elements in the otolith and the change of the ratio of trace elements to calcium(Ca)were analyzed.The differences and the relationship between the otolith and habitat were discussed.The results show that the main trace elements are Ca,Sr,Na,Fe,Ba and Mn.Analysis of variance(ANOVA)reveals no significant difference between populations and genders(P>0.05).There was significant difference in the ratio of trace elements to calcium among different regions of statolith(P<0.01)except for Fe/Ca.The Sr/Ca ratio was the highest in the nucleus and then decreased.There was no significant difference in Sr/Ca ratios among different spawning groups and geographical regions(P>0.05).There was a positive relationship between Sr/Ca and temperature,and a negative relationship with salinity at the larval stage.Sr/Ca can be used as a good temperature indicator.Na/Ca first increased and then decreased,highest at the dark zone.Na/Ca is significantly different among different spawning populations at the nuclear and post nuclear zones(P<0.01).Mn/Ca and Ba/Ca,which first decreased and then increased(lowest in the dark region),increased at the edge zone and peripheral zone.There was a positive relationship between Ba/Ca and salinity at adult stage,and Ba/Ca can be used as an indicator of vertical movement.Fe/Ca was significantly different among different spawning populations and geographic areas(P<0.01).It is shown that Na/Ca and Fe/Ca are suitable for distinguish of different groups of squid,and Sr/Ca and Ba/Ca can be used to estimate the habitat environment of squids in the South China Sea.