DISSERTATION RESEARCH: Assessing controls, fates, and significance of animal egesta in stream ecosystems

论文研究：评估河流生态系统中动物雌激素的控制、命运和重要性

• 批准号: 1501703
• 负责人: Michelle Evans-White
• 金额: $ 1.9万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501703&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Assessing; controls; fates

Animals can play key roles in freshwater ecosystems by converting food resources into waste products that affect the cycling of nutrients such as nitrogen and phosphorus. Previous research has focused on the ecological importance of dissolved wastes (e.g. ammonium and phosphate) from animals, termed excreta, because these wastes are nutrient-rich and readily bioavailable to plants and bacteria. However, animals also produce substantial amounts of particulate wastes, termed feces. For example, leaf-shredding stream invertebrates convert plant litter into fine particulate feces that can be subsequently transported downstream, broken down, or consumed by other animals. Feces may vary widely in attributes depending on diet and the source animal, suggesting species-specific roles of animal feces in larger functioning of ecosystems. In this project, researchers will explore factors influencing attributes of animal feces and compare the impact of feces on nutrient cycling to that of excreta in stream ecosystems. This project will benefit society by contributing novel information about the importance of animals in ecosystems and providing career development for multiple undergraduates and one graduate student. Results can help guide management of human activities that drive changes in animal species distribution and nutrient pollution in freshwaters.This project will employ a combination of laboratory experiments and field surveys to assess controls, fates, and the significance of animal egesta (feces) in stream ecosystems. Dominant grazing and shredding macroinvertebrates from multiple species will be brought to the laboratory, fed diets of low or high nutrient content, and their egesta collected to characterize size and chemical binding as well as measure rates of microbial decomposition and nutrient leaching, uptake, and mineralization over the course of several months. Recurrent surveys of an Ozark headwater stream will quantify total excretion and egestion of carbon, nitrogen, and phosphorus by extant macroinvertebrates and compare these animal fluxes to background stocks and fluxes of dissolved nutrients (in the case of excreta) and fine particulate organic matter (in the case of egesta). All findings will be synthesized for modeling of how variation in background nutrient concentrations, animal community composition, and background stocks and fluxes of dissolved and particulate elements can affect the roles of animals in stream ecosystems.

动物可以通过将食物资源转化为影响氮和磷等营养物质循环的废物，在淡水生态系统中发挥关键作用。先前的研究重点关注动物溶解废物（例如铵和磷酸盐）（称为排泄物）的生态重要性，因为这些废物营养丰富且易于被植物和细菌生物利用。然而，动物也会产生大量的颗粒废物，称为粪便。例如，撕碎树叶的无脊椎动物将植物凋落物转化为细颗粒粪便，随后可以将其输送到下游、分解或被其他动物消耗。根据饮食和来源动物的不同，粪便的属性可能有很大差异，这表明动物粪便在生态系统更大功能中的物种特异性作用。在该项目中，研究人员将探索影响动物粪便属性的因素，并将粪便对养分循环的影响与河流生态系统中的排泄物进行比较。该项目将通过提供有关动物在生态系统中的重要性的新颖信息并为多名本科生和一名研究生提供职业发展来造福社会。结果可以帮助指导人类活动的管理，这些活动推动了淡水中动物物种分布和营养物污染的变化。该项目将采用实验室实验和现场调查相结合的方式来评估河流中动物粪便（粪便）的控制、命运和重要性生态系统。来自多个物种的主要放牧和粉碎的大型无脊椎动物将被带到实验室，喂食低或高营养含量的饮食，并收集它们的雌激素，以表征大小和化学结合，并测量微生物分解和养分浸出、吸收和矿化的速率在几个月的时间里。对奥扎克源头河流的定期调查将量化现存大型无脊椎动物对碳、氮和磷的总排泄和吸收，并将这些动物通量与背景库存和溶解营养物（排泄物）和细颗粒有机物（在排泄物中）的通量进行比较。埃斯塔的情况）。所有研究结果都将被综合起来，用于模拟背景营养浓度、动物群落组成、溶解元素和颗粒元素的背景库存和通量的变化如何影响动物在河流生态系统中的作用。