Developing a multi-chemical tracer method for quantifying temporal variation in food web structure and dynamics

食物网定义了能量、营养和污染物在生物群落或生态系统内的路径和运动，或者更简单地说，定义了取食者和被摄食者的营养等级。所有的有机体都嵌入到食物网中，它们获得的能量、营养和污染物的数量对生存至关重要。世界上的许多生态系统受到人类管理资源的行动和努力的严重影响，这最终可能改变生态系统中能够生存的有机体的类型和数量。不幸的是，食物网的研究是出了名的困难。传统的方法是检查胃内容物，这有许多缺点(例如，内容物以不同的速度消化)，而且通常很困难(例如，胃很小)。最近，化学示踪剂，如氮和碳的稳定同位素和脂肪酸，已经被用来提供一种描述方法来建立食物网络结构。尽管这些示踪剂改善了我们对食物网的研究，但仍然需要在不同环境条件下的受控实验室和实地研究下对其进行校准和验证。我的研究将在实验室和野外研究的盐度和温度梯度下校准一系列已建立的和新型的化学示踪剂。据预测，水生系统中盐度和温度的变化将是气候变化的主要后果。如果要正确理解食物网的特征和人为压力的影响，就必须对化学示踪剂进行校准。了解食物网的功能对于适当的保护和管理以及最终健康和可持续的生态系统是至关重要的。

Food webs define the pathways and movement of energy, nutrients and contaminant within a biological community or ecosystem, or more simply, a trophic hierarchy of feeders and fed upon. All organisms are embedded within food webs, and the amounts of energy, nutrients and contaminants it receives are critical for survival. Many of the world's ecosystems are heavily influenced by man's actions and efforts to manage resources, which can ultimately change the types and amounts of organisms that can survive in an ecosystem. Unfortunately, food webs are notoriously difficult to study. The conventional method is to examine stomach contents, which has a number of drawbacks (e.g., contents are digested at different rates) and is often difficult (e.g., very small stomach size). Recently, chemical tracers, such as stable isotopes of nitrogen and carbon and fatty acids, have been used to provide a descriptive method for establishing food web structure. Although these tracers have improved our study of food webs there is still a need to calibrate and verify them under controlled laboratory and field studies under varying environmental conditions. My research will calibrate a wide suite of established and novel chemical tracers in laboratory and field studies under salinity and temperature gradients. Changes to salinity and temperature in aquatic systems are forecasted to be major consequences of climate change. Calibrations of chemical tracers are imperative if characterization of food webs and the impact of anthropogenic stress are to be proper understood. Understanding how food webs function is essential for proper conservation and management and ultimately healthy and sustainable ecosystems.