Biological fractionation of Zn isotopes in aquatic invertebrates

• Published in: Chinese journal of geochemistry Vol. 25; no. B08; p. 203
• Main Author: R. Douglas Evans David C. Lasenby
• Format: Journal Article
• Language: English
• Published: 2006
• Subjects: 同位素; 无脊椎动物; 生物分馏; 生物地球化学
• ISSN: 1000-9426; 1993-0364

Recent advances in analytical instrumentation have made it more feasible to measure isotope ratios of many elements. In particular, modem multicollector-inductively coupled plasma mass spectrometers can measure isotope ratios of many elements with extremely high precision. As a consequence, we can begin to explore biological fractionation in a systematic way and hence develop isotope ratio measurements as a tool to explore the environmental geochemistry of trace metals. In this presentation we will discuss the problems and potential of measuring isotope ratios of zinc in biological samples from systems with non-specific contamination. This will include such issues as the importance of matrix removal to the measurement of valid isotope ratios, mass bias correction and the availability of standard reference materials. Recent data on isotope ratios of Zn in the aquatic invertebrate Mysis relicta will be presented. These animals are of particular interest because they changed their feeding pattern from juveniles to adults. Thus they can be used to test the hypothesis that differences in the isotopic signature of food sources may determine receptor signatures. The data indicate that there are significant differences in signatures at the different life stages. However, the continual uptake and loss of metals over an organism＇s life span may also lead to fractionation.