Biochemical tracers in freshwater ecosystems

脂肪，包括脂肪酸，是压力的敏感指标，以可预测的方式对环境变化做出反应。一些脂肪酸对维持包括人类在内的所有动物的最佳生理表现至关重要。这些脂肪酸被称为必需脂肪酸(EFA)。在哺乳动物中，EFA在维持心血管和神经健康方面具有重要作用。在无脊椎动物和鱼类中，它们被认为可以促进正常的发育、生长和繁殖。EFA主要在水生生态系统中产生，并通过各种机制(捕食、昆虫涌现、岸上漂流等)从那里转移到陆地生态系统。因此，至关重要的是要了解它们在水生生态系统内以及在水生生态系统和邻近陆地生态系统之间的生产和分布所面临的全球威胁。有可能影响食物链底部(即藻类)的EFAs生产的三种大规模应激源。其中包括：气候变化、外来入侵者和富营养化。脂肪酸的另一个特殊特征是它们作为生物标志物的能力(通过草食或捕食过程从一个有机体传递到另一个有机体的化合物，没有变化)。该项目的目标是：a)在实验室详细研究气候变化(气温升高)对藻类中EFA产生的影响，包括将其转移到浮游动物(草食动物)中；b)提炼和开发新的生化示踪剂，使研究人员能够跟踪与外来入侵者(斑马贻贝)有关的碳在整个水生食物网中的流动，从而更深入地了解外来入侵者的全面影响；以及c)展示随着时间的推移，在藻类中产生的EFA如何随着年龄的增长保留在小鼠大脑中的选定区域。更透彻地了解全球对全民教育生产的威胁，以及这可能如何影响其向陆地生物的转移，将为我们保护我们独特和宝贵的淡水生态系统提供新的强大动力。

Lipids, including fatty acids, are sensitive indicators of stress that respond, in predictable ways, to changes in the environment. Some fatty acids are critical to the maintenance of optimal physiological performance in all animals including humans. Those fatty acids are called essential fatty acids (EFAs). In mammals EFAs are known to be important in the maintenance of cardiovascular and neural health. In invertebrates and fish they are known to promote normal development, growth and reproduction. EFAs are primarily produced in aquatic ecosystems and from there are transferred to terrestrial ecosystems via a variety of mechanisms (predation, insect emergence, shore drift etc). Therefore it is critically important to understand global threats to their production and distribution within aquatic ecosystems and between aquatic ecosystems and neighboring terrestrial ecosystems. Three large-scale stressors that have the potential to impact the production of EFAs at the base of the food chain (i.e. in algae). These include; climate change, exotic invaders and eutrophication. Another special feature of fatty acids is their ability to act as biomarkers (compounds that are passed, unchanged, from one organism to another through the processes of herbivory or predation). This project is targetted towards; a) a detailed examination, in the laboratory, of the effects of climate change (temperature increases) on the production of EFAs in algae including their transfer to zooplankton (herbivores), b) refining and developing new biochemical tracers that will allow researchers to track the flow of carbon associated with exotic invaders (zebra mussels) throughout the aquatic food web and thus gain a deeper understanding of the full scale of exotic invader impacts, and, c) showcase how EFAs, produced in algae, are retained, through time, in selected regions in the the brains of mice as they age. A more thorough understanding of the global threats to EFA production and how this may affect their transfer to terrestrial organisms will provide us with a new and powerful incentive to conserve our unique and precious freshwater ecosystems.