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

稳定的碳和氮特征已被证明有助于重建海洋鱼类的洄游路径和食物网。耳石特别适合于这种分析，因为它们包含了鱼在其整个生命过程中所经历的环境和生理条件的日期记录。然而，由于耳石中存在少量有机物质，稳定同位素分析的全部潜力尚未实现。因此，研究人员将开发一种新技术，基于移动线同位素比质谱法，用于海洋鱼类耳石中少量（2-5 nmol）纯化氨基酸中d13 C和d15 N比的化合物特异性分析。一旦开发出来，该技术将适用于任何需要测量有机材料中C和N同位素的应用，其中样品数量有限。当这些数据与耳石文石的无机同位素和微量元素化学中记录的迁移信息相结合时，这些数据将是变革性的，因为研究人员不仅能够确定个体鱼生活在哪里，而且还可以确定它在整个生命中吃什么。更广泛的影响包括支持一名学生的博士研究，并将研究纳入调查员教授的课程。 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重要信息，从而造福社会。使用比大量C和N更富营养性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。这将反过来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更迭中探索这些关系，以及西大西洋的营养级联

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