Comparison of methods to determine algal δ13C in freshwater
Comparison of methods to determine algal δ13C in freshwater
复制标题
淡水中藻类 δ13C 测定方法的比较
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
D. Planas
中科院分区：
文献类型：
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作者：
J. Marty;D. Planas
为了使用稳定同位素准确评估食物网中向更高营养水平的质量和能量通量，需要基源的同位素特征。在研究水生食物网时，很难获得藻类的特征，因为从大量样本中分离小生物存在挑战。在这项研究中，我们比较了从文献中使用五种方法获得的淡水藻类δ13C值。结果表明，水蚤（Daphnia sp.）等初级消费者、经过藻类生物量校正的颗粒有机碳和分离的藻类样品的特征具有可比性。相比之下，基于二氧化碳和藻类碳分馏特征的藻类δ13C值显著低于其他方法。这种方法产生的不一致值可能是由于基于当前模型确定分馏值时存在问题，并且可能与藻类对碳酸氢盐的吸收有关。
To accurately assess the flux of mass and energy to higher trophic levels in a food web using stable isotopes, the isotopic signature of basal sources is required. When studying aquatic food webs, it is difficult to obtain a signature for algae because of challenges associated with isolating small organisms from a bulk sample. In this study, we compared freshwater algal δ13C values obtained using five approaches from the literature. Results indicated that the signatures derived from a primary consumer such as Daphnia sp., from particulate organic carbon with a correction for algal biomass, and from isolated algal samples were comparable. By contrast, algal δ13C values based on the signature of carbon dioxide and algal carbon fractionation were significantly lower than those of the other approaches. The inconsistent values produced by this method were likely due to problems in determining fractionation values based on current models and were potentially related to bicarbonate uptake by algae.