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

我们小组的研究兴趣包括了解脂质代谢，以便我们可以使用脂质作为追踪碳流的工具。具体而言，我们感兴趣的是使用脂肪酸（FA）在海洋环境中的碳循环和食物网动态的研究。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。我们建议继续我们正在进行的工作调查FA从猎物到捕食者在低营养级，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。FA在不同种类的猎物的比例是不同的，并通过对消费者进行微小的修改，使我们能够跟踪这些FA签名从猎物到消费者的脂肪储存;和2）稳定同位素的特定FA。碳同位素的分布在特定的FA的猎物物种往往是不同的，也传递给消费者几乎没有变化，使我们能够使用稳定的FA同位素作为一个额外的示踪剂。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，我们建议进行一系列的控制饲养实验，大西洋狭鳕（Pollachius virens）作为一个模型物种，以量化任何可能发生的FA的变化。有了对生物化学变化的清晰理解，我们可以构建数学模型来使用FA信息确定鱼类饲料。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，我们正在开发的应用程序在一些不同的环境中的食物网结构的研究。具体来说，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.