SGER: A New Method for Trophic Reconstructions of Marine Fishes From d13C and d15N Analyses of Individual Amino Acids in Otoliths

稳定的碳氮特征在重建海洋鱼类的迁徙路径和食物网中被证明是有用的。耳石特别适合于这种分析，因为它们包含了鱼一生中所经历的环境和生理条件的年代记录。然而，稳定同位素分析的全部潜力尚未实现，由于少量的有机物质存在于耳石。因此，研究人员将开发一种基于移动线同位素比值质谱法的新技术，用于从海洋鱼类耳石中提取的少量（2-5 nmol）纯化氨基酸中d13C和d15N的化合物特异性分析。一旦开发成功，该技术将适用于任何需要测量样品数量有限的有机材料中的C和N同位素的应用。当这些数据与耳石文石的无机同位素和微量元素化学记录的迁徙信息相结合时，这些数据将是革命性的，因为研究人员不仅可以确定一条鱼生活的地方，还可以确定它一生都吃什么。更广泛的影响包括支持一名学生的博士研究，并将研究纳入研究者教授的课程。这项研究还将为制定海洋捕捞渔业生态系统管理战略提供关键信息，从而造福社会。使用比大量C和N更富营养分馏的氨基酸无疑将提高基于C和N同位素的饮食研究的分辨率。反过来，这将使渔业科学家更好地了解气候和渔业生产之间的联系，并在美国西海岸过去的政权转变和西大西洋的营养级联中探索这些关系

Stable carbon and nitrogen signatures have proved useful in reconstructing migratory pathways and food webs in marine fishes. Otoliths are particularly amenable to suitable for such analyses because they contain a dated record of environmental and physiological conditions experienced by a fish throughout its life. However, the full potential of stable isotope analysis has yet to be realized due to the small quantity of organic material present in otoliths. Hence, the investigators will develop a new technique, based on moving wire isotope ratio mass spectrometry, for compound-specific analyses of d13C and d15N ratios in small (2-5 nmol) amounts of purified amino acids from otoliths in marine fishes. Once developed, the technique will be suitable for any application that requires measurement of C and N isotopes in organic material where sample quantity is limited. These data will be transformative when coupled with migratory information recorded in the inorganic isotope and trace element chemistry of otolith aragonite because researchers will be able to determine not only where an individual fish was living, but also what it was eating, throughout its life. The broader impacts include support for the PhD research of one student and incorporation of the research into courses taught by the investigator. The research will also benefit society by providing critical information for the development of ecosystem management strategies for marine-capture fisheries. The use of amino acids that fractionate trophically more than bulk C and N will undoubtedly improve resolution of diet studies based on C and N isotopes. This will, in turn, allow fisheries scientists to better understand the links between climate and fisheries production, and to explore these relationships during past regime shifts on the west coast of the U.S., and trophic cascades in the western Atlantic Ocean