生物对环境元素和稳定同位素的选择性及研究实例

Biological selectivity of environmental elements and stable isotopes and its examples

利用现代生物学最新研究成果和研究模式,对生物及其生活环境中的元素和稳定同位素之间存在的对应关系进行总结和分析认为,生物因生理、地化环境、元素形态及其利用原则等内外因子而对其生活环境中的元素和稳定同位素存在不同程度的选择性吸收、利用和富集,具体的选择性利用机制均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,分别表现为时代效应、耐受限度效应和生态幅重叠等效应等。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泥盆纪腕足类Rhynchospirifer属和Stringocephalus属为代表的生物壳体"第二层"及其围岩的研究中得到验证。

Used fully present achievements of biology and took current biological model as an example, the relationship of different elements and stable isotopes in life-forms and their living environments have been analysed and summarized. Based on the differences of their physiology, geochemistry, chemical formation and principle of utilization, life-forms possess different levels of selective absorbability, utilization and enrichment on various elements and stable isotopes in their living environments. The exact mechanism of their selectivity can be explained by its body structures through their molecular levels. When the elements and stable isotopes in their living environments changed, life-forms do not make totally consistent responses to these changes according to their different ecological amplitudes and endurances. They are expressed by time effect, endurance effect and the overlap of ecological amplitude effect respectively. The δ^13C and δ^18O and their tendencies of changes in the ＂second layer＂ of some fossil shells and their surrounding rocks keep good consistence. The above cognitions have been tested in different extents by the corresponding studies of Devonian brachiopod Rhynchospirifer, Stringocephalus and their bearing rocks.