Collaborative Research: Extending the potential for hydrogen isotope tracers in ecology: experiments, biochemistry and field studies

动物组织氢同位素组成已成为研究动物运动和栖息地利用的重要工具。然而，动物生态学家自信地将同位素分析应用于生态问题所需的生化基础尚未充分揭示。该项目将通过促进我们对脊椎动物组织中控制同位素组成的基本过程的理解来解决这一知识差距。新的方法将用于分析动物组织中单个氨基酸的化合物特异性同位素，并确定氢是否可以直接从膳食氨基酸进入组织。生物合成机制负责确定氢同位素模式观察到的大块组织将探索在一系列的实验室实验。本研究的结果将解决动物组织中同位素识别变化的幅度和程度，以及氢从食物和水进入动物组织的生化机制。为了完成这项工作，罗非鱼将在具有独特和可控同位素组成的水和食物成分的水箱中饲养。单个氨基酸的同位素组成，特别是那些生长所必需的氨基酸，将被测量，以追踪从膳食蛋白质、碳水化合物、脂质和水进入鱼类组织的情况。这项研究将扩展到一项以黑喉蓝莺为基础的种群研究，该研究将在北美跨越大陆范围的三个地点测量来自羽毛、骨骼和肝脏组织的单个氨基酸的氢同位素组成。该项目的研究成果将为同位素方法在动物生态学和行为学研究中的应用提供新的方法和基础知识。该项目将开发和教授一门同位素生态学的研究生课程，让本科生参与实验室研究，并向高中生物课推广，以促进对生化生态学的理解。它还将支持旨在提高人们对稳定同位素在生物科学中的潜在用途的认识的讲习班，并为今后与几个拉丁美洲国家的研究人员合作奠定基础。

The hydrogen isotopic composition of animal tissues has become as a valuable tool in the investigation of animal movements and the study of habitat use. However, the biochemical foundation needed for animal ecologists to confidently apply isotopic analyses to ecological problems has yet to be adequately revealed. This project will address that knowledge gap by advancing our understanding of fundamental processes controlling isotopic composition in tissues of vertebrates. New methodologies will be applied to analyze compound-specific isotopes of individual amino acids in animal tissues and to determine whether hydrogen can be directly routed from dietary amino acids into tissues. Biosynthetic mechanisms responsible for determining hydrogen isotope patterns observed in bulk tissues will be explored in a series of laboratory experiments. Results from this research will address the magnitude and degree of variation in isotope discrimination for animal tissues, and the biochemical mechanism of hydrogen incorporation into an animal's tissue from its food and water. To accomplish this work, the fish species tilapia will be reared in tanks with water and food components having unique and controlled isotopic compositions. The isotopic composition of individual amino acids, particularly those that are indispensible for growth, will be measured to trace incorporation from dietary protein, carbohydrate, lipid, and water into fish tissues. The research will be extended to a population-based study of black-throated blue warblers, for which the hydrogen isotopic composition of individual amino acids from feather, bone, and liver tissues will be measured from three locations that span the continental range for this bird species in North America. Results from this project will advance a new methodology and provide foundational knowledge for isotopic approaches to the study of animal ecology and behavior. The project will develop and teach a graduate level course on isotopic ecology, involve undergraduate students in the laboratory research, and conduct outreach to high school biology classes to foster understanding of biochemical ecology. It will also support workshops designed to raise awareness of the potential uses of stable isotopes in the biological sciences and set the stage for future collaboration with researchers in several Latin American countries.