生物对环境微量元素和稳定同位素的选择性及研究实例  

CASE STUDIES OF BIOLOGICAL EFFECTS ON TRACE ELEMENTS AND STABLE ISOTOPES

作　　者：刘疆[1,2] 白志强[3] 

机构地区：[1]海南省地质勘查局 [2]海南省海洋地质调查局,海南海口570206 [3]北京大学地球与空间科学学院,北京100871

出　　处：《地层学杂志》2009年第2期155-164,共10页Journal of Stratigraphy

基　　金：国家自然科学基金(No.40372018)资助

摘　　要：生物对其生活环境中的不同元素和同位素存在不同程度的选择性吸收、利用和富集。其影响因子分为内因和外因两大类。具体选择机制可以从生物的形态构造直至分子水平上加以解释。当环境中元素、同位素含量发生变化时,生物因其对各元素生态幅和耐受限度的差异而并不完全对环境中化学因子的变化产生一致性的响应。生物对其耐受限度较小的元素保持较高的属内有效性和特异性选择;而对于生态幅较宽的元素,生物属内的特异性选择弱化,生态幅可能与它属生物发生部分重叠。部分生物壳体"第二层"与其围岩碳、氧同位素比值及其变化趋势保持着较好的一致性。上述认识不同程度地在Rhynchospirifer属和Stringocephalus属为代表的腕足动物及其围岩的研究中得到验证。Organisms have different levels of selective absorbability, utilization and enrichment on different elements and stable isotopes in their living environments. The exact mechanisms of the selectivity can be explained by its body structures through the molecular level. Due to environmental changes in trace elements and stable isotopes, and their different ecological amplitudes and biological tolerance, organisms do not have consistent responses to these changes. For those elements with narrow biological tolerance, lifeforms have a greater effect and specialized selectivity. And for those elements with wide ecological ampli- tudes, biological effects and selectivity are weakened. These ecological amplitudes may be overlapped between different life-forms. The δ^13C and δ^18O and their tendency of changes in the ＂secondary layers＂ of some fossil shells and their surrounding rocks are consistent. These responses are tested in different extents using the brachiopod fossils Rhynchospirifer and Stringocephalus, as well as their surrounding rocks.

关 键 词：生物选择性 元素 稳定同位素 化学地层学 Rhynchospirifer Stringocephalus 腕足动物 

分 类 号：P534[天文地球—古生物学与地层学]