Effects of antimicrobial compounds on aquatic communities via bottom-up regulation (AQUA-CO-REG)

分解外来粗颗粒有机物，如落叶，是淡水生态系统的一项基本功能，为当地和下游社区提供能源。其前身项目AQUA-REG使用抗菌物质研究自下而上的影响途径，重点是叶片微生物和食腐动物切碎机水平。建立了水生丝孢菌的Q-RT-PCR检测方法。AQUA-REG的结果发表在7篇同行评审论文中，更多的论文正在编写中。本提案旨在将AQUA-REG方法应用于模型大型无脊椎动物群落水平，即包括无脊椎动物捕食者。为此，将采用一个新设计的河流微观系统，由近自然的源头河流连续供水。使用先前建立的抗菌剂作为标准化的化学应激源，AQUA-CO-REG通过污染的叶片材料暴露模型群落。除了在动态能量收支理论中已经考虑的主要数量（例如能量的量）联系之外，在AQUA-CO-REG中，将从食物网的角度进一步考虑例如食物的非必需和必需脂肪酸组成的意义上的“能量的质量”。稳定同位素分析和基于Q-RT-PCR的丝孢菌定量将补充所研究的一套终点。考虑到水生食物网中抗菌剂诱导的自下而上的直接效应途径的食物质量，拟议的项目允许确定影响的大小，以及了解在社区层面上与这些影响相关的机制，如摄食可塑性，呼吸，应激耐受性或捕食者回避。

The breakdown of allochthonous coarse particulate organic matter like leaf litter is a fundamental function in freshwater ecosystems providing energy for local but also downstream communities. The predecessor project AQUA-REG has used antimicrobial substances to study bottom-up effect pathways with a focus on the leaf microorganismic and detritivore shredder level. Q-RT-PCR protocols for aquatic hyphomycetes were developed. AQUA-REG results were published in seven peer-reviewed papers, further papers are under preparation. The present proposal aims to take the AQUA-REG approach to the level of model macroinvertebrate communities, i.e. including invertebrate predators. To this end, a newly designed stream microcosm system fed continuously by water from a near-natural headwater stream will be employed. Using the previously established antimicrobials as standardized chemical stressors, AQUA-CO-REG exposes model communities via contaminated leaf material. Besides the mainly quantitative (e.g. amount of energy) linkages already considered e.g. in the dynamic energy budget theory, the “quality of the energy” in the sense of, for instance, non-essential and essential fatty acid composition of food, will be further considered in AQUA-CO-REG from a food web perspective. Stable-isotope analysis and Q-RT-PCR-based hyphomycete quantifications will complement the suite of endpoints looked at. Considering food quality for bottom-up directed effect pathways induced by antimicrobials in aquatic food webs, the proposed project allows to determine the magnitude of effects as well as to understand the mechanisms relevant for these effects at the community level, such as feeding plasticity, respiration, stress tolerance or predator avoidance.