镉同位素生物分馏实验模拟及地球化学示踪

镉作为潜在的地球化学示踪剂已引起人们的广泛关注，并成功用于表征自然和人为陆源物质、成矿物质来源及海洋营养物质的循环等领域研究。镉同位素分馏主要发生在蒸发/冷凝过程及生物利用过程，生物利用过程导致的分馏效应远大于蒸发/冷凝过程。因此, 探讨镉同位素生物分馏机制，界定各物质储库同位素组成对于镉同位素地球化学的研究具有重要意义。本项目以莱茵衣藻（Chlamydomonas reinhardtii sp.）和小球藻（Chlorella sp.）为实验模板生物，实验研究不同环境条件（温度、盐度、pH、生物量及氧化还原环境）下对镉同位素分馏的制约，探讨生物表面吸附与吸收利用过程导致的同位素分馏效应及分馏机制，界定不同物质储库的同位素组成、分布，并用于华南三个不同水深的二叠系-三叠系界线剖面（沿沟、煤山和上寺剖面）镉同位素组成研究，反演古海洋镉同位素组成，为地球科学、环境科学研究提供一种新的研究手段。

Cadmium as a potential of geochemical tracer has aroused people's attention. Cd isotope fractionations have used to characterize various natural and anthropogenic terrestrial materials, the source of ore-forming materials, Marine nutrient cycle and the evolution. Cadmium isotope fractionations mainly generate in partial evaporation/condensation and biological utilization process. Cd isotope effect in biological utilization process is greater than the evaporation and condensation process. Investigation Cd isotope fractionation mechanism in biological processes and isotopic composition in the different material storage database is of great significance for cadmium isotopic geochemistry. In this project, the Chlamydomonas reinhardtii sp. and Chlorella sp., as the biological experiment template, experimental research the constraint of cadmium isotope fractionation on different environmental conditions (temperature, salinity, pH, biomass and REDOX environment). Explore isotope fractionation effect and fractionation mechanism due to biological surface adsorption and absorption utilization of dissolved Cd and define the scope of isotopic composition and distribution in the different material storage database. The proposed method applied to the investigation of Cd isotopic composition of the P/T boundary section in South China with three different water depth (Yangou，Meishan and Shangsi section), inversion of the ancient Marine Cd isotope composition and distribution. This work would provide a new technology and method for earth science and environmental science.