Laboratory experiments to determine trophic enrichment factors of stables isotope and fatty acid biomarkers in the blue crab, Callinectes sapidus

Stable isotope (SI) and fatty acid (FA) biomarkers provide new ways to understand predator-prey interactions. In particular, quantitative inference about the strength of feeding links can be achieved with biomarker mixing models, whose accurate application requires trophic enrichment factors (TEF) accounting for metabolism, deposition, or synthesis (also known as a “discrimination factors” or “calibration coefficients” for SI and FA, respectively). Nevertheless, many applications of mixing models do not use TEFs developed for the particular predator or conditions of interest (e.g., life stage, diet quality). We conducted a 12-week laboratory experiment to quantify SI and FA TEFs for the ecologically and economically important Blue crab, Callinectes sapidus.稳定同位素（Stable isotope, SI）与脂肪酸（Fatty acid, FA）生物标志物为解析捕食者-猎物相互作用提供了全新研究途径。具体而言，借助生物标志物混合模型可实现对摄食联系强度的定量推断，而该模型的精准应用需依赖营养富集因子（Trophic enrichment factors, TEF）——针对稳定同位素的TEF被称为"分馏因子"，针对脂肪酸的TEF则被称为"校准系数"，二者分别用于校正代谢、沉积或合成过程带来的差异。然而，当前诸多混合模型的实际应用，并未采用针对目标捕食者或特定研究条件（如生物发育阶段、日粮品质）所开发的专属TEF。为此，本研究开展了为期12周的室内受控实验，以量化兼具重要生态价值与经济价值的蓝蟹（Callinectes sapidus）的稳定同位素与脂肪酸营养富集因子。