Food web delineation using lipid tracers

我的主要研究兴趣包括了解脂类代谢，以便我可以将脂类用作追踪碳流动的工具。具体地说，我对脂肪酸(FA)在海洋环境中碳循环和食物网动态研究中的使用感兴趣。FA非常适合这样的研究，因为许多膳食FA被并入消费者，只需对结构进行很小的修改，使FA成为其来源的指示物或生物标记物。我建议继续我正在进行的工作，研究FA从猎物向低营养水平的捕食者转移的情况，目的是开发一个模型来估计捕食者的饮食。我将使用FA数据中的两种不同类型的信息：1)FA签名。在不同种类的猎物中FA的比例是不同的，只需稍加修改就可以传递给捕食者，使我能够追踪这些FA信号从猎物到捕食者脂肪存储；以及2)特定FA的稳定同位素。在被捕食物种的特定FA中，碳同位素的分布通常是不同的，也被传递给捕食者，几乎没有变化，因此提供了一个额外的来源示踪剂。然而，这两种方法都需要研究FA信号中可能发生的微妙生化变化，或者捕食者脂肪储存中消化、沉积和动员的稳定同位素比率。因此，我建议对鳕鱼(Gadus Morhua)和鲑鱼(Salmo Salar)的模型捕食者进行一系列控制摄食实验，以量化FA可能发生的任何变化。有了对生化变化的清楚了解，我可以构建数学模型来使用FA信息来确定鱼的饲料。然后，这些模型可以作为我正在开发的更广泛的碳追踪技术的一部分，应用于研究多种不同环境中的食物网络结构。具体地说，我感兴趣的是将这些模型应用于最容易受到气候变化影响的生态系统，如白令海和西北大西洋，以检测碳循环随时间的变化。

My general research interests involve understanding lipid metabolism so that I can use lipids as a tool to trace carbon flow. Specifically, I am interested in the use of fatty acids (FA) in the study of carbon cycling and food web dynamics in the marine environment. FA are well suited to such studies because many dietary FA are incorporated into consumers with only minor modification to structure, making FA useful as indicators or biomarkers of their source. I propose to continue my ongoing work investigating the transfer of FA from prey to predators at low trophic levels, with the aim of developing a model to estimate predator diets. I will use two different types of information from FA data: 1) FA signatures. The proportions of FA in different species of prey are distinct and are passed to predators with only minor modification, allowing me to trace these FA signatures from prey to predator fat stores; and 2) stable isotopes of specific FA. The distribution of carbon isotopes within specific FA of prey species are usually different and are also passed to predators with little change, thus providing an additional tracer of source. Both approaches, however, require investigation into the subtle biochemical alterations that may occur in FA signatures or stable isotope ratios with digestion, deposition and mobilization in predator's fat stores. Thus, I propose to carry out a series of controlled feeding experiments with model predators of cod (Gadus morhua) and salmon (Salmo salar) to quantify any alterations in FA that may occur. With a clear understanding of biochemical changes, I can construct mathematical models to determine fish diets using FA information. These models can then be applied as part of a broader carbon-tracing technique that I am developing for application to the study of food web structure in a number of different environments. Specifically, I am interested in applying these models to ecosystems most susceptible to effects of climate changes, such as the Bering Sea and the northwest Atlantic, to detect changes in carbon cycling over time.