Validating methods for measuring δ18O and δ13C in otoliths from freshwater fish
Validating methods for measuring δ18O and δ13C in otoliths from freshwater fish
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验证淡水鱼耳石中 δ18O 和 δ13C 的测量方法
DOI：
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发表时间：
2003
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影响因子：
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通讯作者：
M. Power
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文献类型：
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作者：
K. R. Guiguer;R. Drimmie;M. Power
磷酸消化技术从生物源碳酸盐中提取二氧化碳并可靠地再现标准参考物质（NBS-18，NBS-19）中δ 18 O和δ 13 C特征的能力进行了测试，并显示出对非生物材料的准确，无偏测量。在一系列实验中，使用参考标准和从水产养殖的北极红点鲑和虹鳟鱼获得的耳石，也测试了分析生物碳酸盐时，通常报道的焙烧制备方法的影响。焙烧对参考标准的同位素测量没有影响。烤和非烤鱼耳石配对实验的平均氧同位素签名之间没有显着差异被发现。然而，耳石氧同位素测量值显着富集相比，饲养水为基础的测量这两个物种。预期的同位素平衡和测量耳石δ 18 O值之间的协议作为焙烧温度的函数和物种之间的变化。建议选择适当的烘烤温度的标准，并有利于350°C的淡水鱼，其中平均饲养水温和饲养温度的已知差异的无偏估计。碳同位素的不平衡，观察到这两个物种。混合模型分析确定了所研究耳石中代谢来源碳百分比的差异，北极红点鲑由于代谢率较高，从代谢中获得更大比例的耳石δ 13 C。版权所有© 2003年约翰威利父子有限公司。
The ability of the phosphoric acid digestion technique to extract carbon dioxide from biogenic carbonates and reliably reproduce δ18O and δ13C signatures from standard reference materials (NBS-18, NBS-19) was tested and shown to produce accurate, unbiased measurements of non-biologic materials. The effects of roasting preparation methods commonly reported when analyzing biogenic carbonates were also tested in a series of experiments using reference standards and otoliths obtained from aquacultured Arctic charr and rainbow trout. Roasting had no effect on the isotope measurement of reference standards. No significant differences between mean oxygen isotope signatures from paired experiments with roasted and non-roasted fish otoliths were found. However, otolith oxygen isotope measurements were significantly enriched in comparison to rearing water-based measurements for both species. Agreement between expected isotopic equilibrium and measured otolith δ18O values varied as a function of roasting temperature and between species. Criteria for the selection of appropriate roasting temperatures are suggested and favour 350°C in freshwater fish where unbiased estimates of average rearing water temperatures and known differences in rearing temperatures were obtained. Carbon isotopic disequilibria were observed for both species. A mixing model analysis established differences in the percentage of metabolically derived carbon in studied otoliths, with Arctic charr deriving a greater proportion of otolith δ13C from metabolism as a result of higher metabolic rates. Copyright © 2003 John Wiley & Sons, Ltd.