Food web delineation using lipid tracers

我的一般研究兴趣包括了解脂质代谢，这样我就可以使用脂质作为追踪碳流的工具。具体来说，我感兴趣的是脂肪酸（FA）在海洋环境中的碳循环和食物网动态研究中的应用。FA非常适合此类研究，因为许多膳食FA仅对结构进行微小修改就被纳入消费者体内，使得FA可用作其来源的指示剂或生物标志物。我建议继续我正在进行的工作，调查FA从猎物到捕食者在低营养水平的转移，目的是开发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。FA在不同种类的猎物中的比例是不同的，并且只经过微小的修改就传递给捕食者，这使我能够追踪这些FA从猎物到捕食者脂肪储存的特征; 2）特定FA的稳定同位素。碳同位素在被捕食物种的特定FA中的分布通常是不同的，并且也几乎没有变化地传递给捕食者，从而提供了额外的来源示踪剂。然而，这两种方法，需要调查的微妙的生化变化，可能会发生在FA签名或稳定的同位素比与消化，沉积和动员捕食者的脂肪储存。因此，我建议进行一系列的控制喂养实验与模型捕食者的鳕鱼（鳕morhua）和鲑鱼（萨尔莫salar），以量化任何改变FA可能发生。有了对生物化学变化的清晰理解，我可以构建数学模型来使用FA信息确定鱼类饮食。然后，这些模型可以作为一个更广泛的碳示踪技术的一部分，我正在开发的应用程序在许多不同的环境中的食物网结构的研究。具体来说，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.