Investigating marine carbon cycling using fatty acids and their stable carbon isotopes

我的团队的研究兴趣包括了解脂类代谢，以便我们可以将脂类用作追踪碳流动的工具。具体地说，我们对脂肪酸(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。我们建议继续我们正在进行的工作，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。我们将使用来自FA数据的两种不同类型的信息：1)FA配置文件。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消费者，使我们能够从猎物到消费者脂肪商店追踪这些FA信号；以及2)特定FA的稳定同位素。在被捕食物种的特定FA中，碳同位素的分布往往不同，也几乎没有变化地传递给消费者，使我们能够使用FA的稳定同位素作为额外的示踪剂。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，我们建议以大西洋鳕鱼为模式物种进行一系列控制饲养实验，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，我们就可以利用FA信息构建数学模型来确定鱼类的饲料。然后，这些模型可以作为我们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，我们有兴趣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。

The research interests of my group involve understanding lipid metabolism so that we can use lipids as a tool to trace carbon flow. Specifically, we are 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. We propose to continue our 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. We will use two different types of information from FA data: 1) FA profiles. The proportions of FA in different species of prey are distinct and are passed to consumers with minor modification, allowing us to trace these FA signatures from prey to consumer fat stores; and 2) stable isotopes of specific FA. The distribution of carbon isotopes within specific FA of prey species are often different and are also passed to consumers with little change, allowing us to use stable isotopes of FA as an additional tracer. Both approaches, however, require investigation into the subtle biochemical changes that may occur in FA signatures or stable isotope ratios with digestion, deposition and mobilization in predator's fat stores. Thus, we propose to carry out a series of controlled feeding experiments using Atlantic pollock (Pollachius virens) as a model species to quantify any alterations in FA that may occur. With a clear understanding of biochemical changes, we 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 we are developing for application to the study of food web structure in a number of different environments. Specifically, we are 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.