DISSERTATION RESEARCH: Highly unsaturated fatty acid transfer from aquatic to terrestrial food webs

溪流依靠陆地景观中的营养物质为生活在其中的动植物提供燃料。反过来，河流生物，如新兴的水生昆虫，为陆地捕食者，包括河边的鸟类提供能量和营养。出现的溪流昆虫可能是河边捕食者特别重要的食物来源。 过去大多数关于河流和陆地景观之间营养盐运动的研究都是在相对未受干扰的森林中进行的。然而，流衍生的营养物质的河边捕食者的贡献，实际上可能是不太重要的森林流比在农业景观中，藻类和流昆虫丰富的高产流。本研究将考察以下因素的影响：1）食物可用性和质量对代表性河滨鸟类东菲比（Sayornis phoebe）生长率的影响，以及2）农业与森林土地利用对淡水和陆地食物的可用性和质量的影响东菲比雏鸟的食物资源。 研究人员将与当地环境管理人员和土地所有者合作，分享结果摘要，并在公开的研究地点，信息标志将用于解释研究。研究人员将与当地的儿童科学博物馆合作，根据研究主题制作演示文稿，并将继续指导少数民族大学生。食物质量和数量的影响将通过在实验室环境中饲养生长最快时期（第4-9天）的菲比小鸡来测量。将以二乘二设计饲喂数量（高或低热量）和质量（高或低高度不饱和脂肪酸）不同的饲料。每天测量Phoebe小鸡的体重、头长和跗骨长度。为了研究土地利用对自然环境中食物质量和质量的影响，将把小鸡生长测量与脂肪酸成分分析相结合，以量化各个地点的食物质量。 菲比组织的稳定同位素分析及其陆生和水生食物项目将被用来重建菲比获得食物资源。研究人员希望农业用地能为菲比提供更高数量和质量的食物，从而加快菲比的生长速度。将对菲比组织及其陆生和水生食物进行化合物特异性稳定同位素分析，以确定土地利用如何影响菲比获得高度不饱和脂肪酸的地方。研究人员希望在农业地区的phoebes获得由水生初级生产者合成的高度不饱和脂肪酸，而在森林地区的phoebes则从陆地初级生产者合成的分子前体中获得高度不饱和脂肪酸。

Streams depend upon nutrients from terrestrial landscapes to fuel the production of the plants and animals living in them. Reciprocally, stream organisms such as emerging aquatic insects provide energy and nutrients to terrestrial predators, including streamside birds. Emergent stream insects are likely an especially important food source for streamside predators. Most past studies on nutrient movement between streams and terrestrial landscapes have been conducted in relatively undisturbed forests. However, the contribution of stream-derived nutrients to streamside predators may actually be less important in forested streams than in highly productive streams in agricultural landscapes where algae and stream insects are abundant. This research will examine effects of: 1) food availability and quality on the growth rates of a representative streamside bird, the Eastern Phoebe (Sayornis phoebe), and 2) agricultural versus forested land use on the availability and quality of freshwater and terrestrial food resources for Eastern Phoebe chicks. The researchers will collaborate with local environmental managers and landowners by sharing summaries of results, and at publicly accessible study sites, informational signs will be used to explain the research. The researchers will work with a local children's science museum to develop presentations based on the research themes, and will continue to mentor underrepresented minority undergraduates.Effects of food quality and quantity will be measured by raising phoebe chicks during their most rapid period of growth (days 4-9) in lab settings. Chicks will be fed diets that vary in quantity (high or low calorie) and quality (high or low highly unsaturated fatty acids) in a two by two design. Phoebe chick weight, head length, and tarsus length will be measured daily. To examine the effects of land use on food quality and quality in a natural setting, chick growth measurements will be coupled to fatty acid composition analyses to quantify food quality across sites. Stable isotope analyses of phoebe tissues and their terrestrial and aquatic dietary items will be used to reconstruct where phoebes obtain food resources. The researchers expect agricultural sites to provide phoebes with both higher food quantity and quality resulting in faster phoebe growth rates. Compound-specific stable isotope analyses of phoebe tissues and their terrestrial and aquatic dietary items will be performed to determine how land use affects where phoebes obtain highly unsaturated fatty acids. The researchers expect phoebes at agricultural sites to obtain highly unsaturated fatty acids synthesized by aquatic primary producers and phoebes at forested sites to obtain highly unsaturated fatty acids elongated from their molecular precursors synthesized by terrestrial primary producers.