Food web delineation using lipid tracers

我的一般研究兴趣包括了解脂质代谢，以便我可以使用脂质作为追踪碳流的工具。具体来说，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应用很感兴趣。FA非常适合这类研究，因为许多膳食FA仅在结构上进行了微小的修改就被纳入了消费者体内，这使得FA作为其来源的指示器或生物标记物很有用。我建议继续我正在进行的研究工作，在低营养水平上研究FA从猎物到捕食者的转移，目的是建立一个模型来估计捕食者的饮食。我将使用来自FA数据的两种不同类型的信息：1)FA签名。不同种类的猎物中FA的比例是不同的，并且只经过轻微的修改就传递给了捕食者，这使我能够追踪这些FA的特征，从猎物到捕食者的脂肪储存；2)特异FA的稳定同位素。被捕食物种特定FA内的碳同位素分布通常不同，并且传递给捕食者的碳同位素变化不大，从而提供了额外的来源示踪剂。然而，这两种方法都需要研究在捕食者脂肪储存的消化、沉积和动员过程中，FA特征或稳定同位素比率可能发生的细微生化变化。因此，我建议对鳕鱼（Gadus morhua）和鲑鱼（Salmo salar）的模式捕食者进行一系列的控制喂养实验，以量化可能发生的FA变化。有了对生物化学变化的清晰认识，我可以利用FA信息构建数学模型来确定鱼类的日粮。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许多不同环境下的食物网结构。具体来说，我感兴趣的是将这些模型应用于最易受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.