The Keystone Role of Heterotrophic Microbes in Driving Ecosystem-level Effects of Nutrient Enrichment

a . D. Rosemond， J. B. Wallace， K. Suberkropp本项目建立在之前向阿巴拉契亚山脉南部的一条水源添加营养物质的基础上。这种添加导致了陆源有机物的快速分解，增强了微生物的生产，特别是真菌，并提高了无脊椎动物的生产力。这项拟议的研究旨在分离真菌和细菌在以碎屑为基础的系统中的相对重要性。我们将继续添加营养物质，并通过在处理流程中添加杀菌剂来消除微生物群落的真菌成分。通过大量减少真菌，我们将评估它们对生态系统过程的重要性，如凋落物分解、整体微生物生产和呼吸、无脊椎动物次生生产、悬浮颗粒出口和有机物储存。我们的假设将测试以碎屑为基础的系统中真菌和细菌之间关系的性质和类型，即真菌和细菌是竞争碳和营养物质还是相互补充？这项研究增加了我们对微生物多样性在生态系统功能中的重要性的认识。

The keystone role of heterotrophic microbes in driving ecosystem-level effects of nutrient enrichment A. D. Rosemond, J. B. Wallace, K. Suberkropp This project builds on a previous nutrient addition to a headwater stream in the southern Appalachian Mountains. This addition resulted in rapid decomposition of terrestrially derived organic matter, enhanced microbial production, especially fungi, and elevated invertebrate productivity. The proposed study is designed to separate the relative importance of fungi and bacteria in detritus-based systems. We will continue to add nutrients and eliminate the fungal component of the microbial community by adding a fungicide to the treatment stream. By greatly reducing fungi we will assess their importance to ecosystem processes such as litter decomposition, overall microbial production and respiration, invertebrate secondary production, suspended particle export, and organic matter storage. Our hypotheses will test the nature, and types of relationships between fungi and bacteria in detritus-based systems, i.e. do fungi and bacteria compete for carbon and nutrients or do they complement each other? This study adds to our understanding the importance of microbial diversity in ecosystem functions.