Production, transport, fate and effects of lipids in the marine environment

这项研究是关于将海洋食物网络研究提升到一个新的水平，无论是我们正在探索的东西，还是我们正在如何做到这一点。我们将看到脂质是如何从食物网的一个层面转移到下一个层面的，我们将使用一种新的非常复杂的分析方法来测量整个脂类化合物套件。脂类是生命所必需的，为细胞膜提供能量和结构，并为生物体中的化学信使提供能量。脂类是在饮食和温度等因素的影响下通过生物过程产生的。*水生生态系统占据了生物圈的最大部分，这些系统中的脂类提供了最密集的能量形式。脂质动力学也可以强烈地影响海洋食物网中污染物的积累。在脂质中，某些必需脂肪酸，如长链omega-3多不饱和脂肪酸(PUFA)，以及类固醇，如胆固醇，被认为是生态系统健康和稳定的驱动力。这项研究是我们正在进行的项目的继续，目的是调查类脂在海洋生物中的重要性以及这些富碳化合物在海洋食物网中的循环。*目标*我的长期目标是量化类脂在海洋环境中的生产、运输、最终命运和影响，特别是在全球变化的背景下。*在这里，我的第一个目标是比较研究不足的冷水和暖水生态系统中类脂的生产、运输和命运。与我的三名学生和一名新学生一起，我们将研究四个截然不同的食物网络：1)位于纽芬兰西北大西洋的深海食物网络，2)纽芬兰附近的亚北极洲罗多里斯床，3)加利福尼亚州海湾的亚热带真金枪鱼食物网络，以及4)西南太平洋的亚热带金枪鱼食物网络。我的第二个目标是使用新的分析技术，与一名新学生一起研究饮食、温度和酸度的变化对生物膜化学成分的影响。除了我的第一个目标，我的第三个目标是确定是否存在在海洋生态系统中运行的替代生物合成途径来合成关键的多不饱和脂肪酸。在全球变化的背景下，了解深层和/或寒冷生态系统中存在的必需脂肪酸的来源尤其重要。*影响*生态系统中能量流动的特征是生态学的主要目标之一，而分析不同水平的食物网如何相互作用是量化其流动的关键。脂肪是这些研究的核心，每克产生的能量是蛋白质或碳水化合物的两倍以上，并提供必要的脂肪酸、植物类固醇和胆固醇，以及通过详细分析类脂化合物来量化联系的手段。因此，确定类脂的来源、丰度和转移将有助于有效监测海洋生态系统的可持续性和健康。

This study is all about taking it to the next level in marine food web research, both in terms of what we are probing and how we are doing it. We will see how lipids are transferred from one level of the food web to the next level up and we will use a new very sophisticated analytical approach to measuring entire suites of lipid compounds. Lipids are essential for life, providing energy, structure to cell membranes, and chemical messengers in organisms. Lipids are made biologically by processes under the influence of factors such as diet and temperature.**** Aquatic ecosystems occupy the largest part of the biosphere, and lipids in those systems provide the densest form of energy. Lipid dynamics can also strongly influence pollutant accumulation in marine food webs. Among the lipids, certain essential fatty acids such as long-chain omega-3 polyunsaturated fatty acids (PUFA), and sterols such as cholesterol are considered to be drivers of ecosystem health and stability. This study is a continuation of our ongoing program to investigate the importance of lipids in marine organisms and the cycling of these carbon-rich compounds in marine food webs.****Objectives**** My long-term goal is to quantify production, transport, ultimate fate and effects of lipids in the marine environment, especially in the context of global change.****Here my first objective is to compare lipid production, transport and fate in understudied cold and warm water ecosystems. With three of my current students and one new one we will examine four highly contrasted food webs: 1) The deep-sea food web located in the northwest Atlantic off Newfoundland, 2) Subarctic rhodolith beds off Newfoundland, 3) The subtropical euphausiid food web in the Gulf of California, and 4) The subtropical tuna food web in the southwest Pacific Ocean. My second objective is to examine the effect of changes in diet, temperature and acidity on the chemical composition of biological membranes with a new student, using new analytical technology. In tandem with my first objective, my third objective is to determine if there is an alternative biosynthetic pathway that is in operation in marine ecosystems for synthesizing critical PUFA. Knowing the origin of essential fatty acids present in deep and/or cold ecosystems is particularly important in the context of global change.****Impact**** The characterization of energy flow in ecosystems is one of the main goals of ecology, and the analysis of how different levels of the food web interact is key to quantifying its flow. Lipids are central to these studies yielding more than twice the amount of energy per gram than proteins or carbohydrates, and providing essential fatty acids and phytosterols and cholesterol as well as a means to quantify the connections through detailed analysis of lipid compounds. Thus determination of the origin, abundance, and transfer of lipids will aid in effective monitoring of the sustainability and health of marine ecosystems.*******