DISSERTATION RESEARCH: The Influence of Antibiotic Compounds on Soil Microbial and Invertebrate Communities

抗生素的发现是20世纪的科学突破之一。虽然许多人都熟悉抗生素是如何用于人类健康的，但今天生产的绝大多数抗生素是用来促进牲畜的健康和生长的。与许多药物一样，高达80%的活性抗生素总剂量会通过动物粪便和尿液等排泄物排出，并进入周围环境。尽管之前的研究发现，牲畜农场附近的抗生素抗性生物比一般情况下更多，但科学家们并不完全了解来自牲畜粪便的抗生素如何影响接触它们的土壤中的重要生物：土壤微生物，如细菌和真菌，以及无脊椎动物，如千足虫、虫虫、蜘蛛和昆虫。健康的微生物和无脊椎动物群落负责循环利用土壤中的营养物质，并使植物和以它们为食的动物可以利用这些营养物质。这项研究将帮助科学家了解在土壤中添加抗生素的常见做法，通过将受污染的牲畜粪便施用于作物土壤，可能会破坏养分循环的土壤生物，以及这些生物如何很好地获得养分。通过这项研究，科学家、农民和公众可以促进负责任的废物管理做法，这将有助于保护我们的生态系统，造福人类健康。该项目还将培训一名研究生和美国印第安志愿者研究人员。利用含有抗生素（四环素）的牛粪，本研究将包括一系列实地实验，以评估抗生素化合物如何改变土壤中的分解速率、微生物呼吸（碳和养分循环的重要因素）以及微生物和无脊椎动物群落组成。研究人员还将测试在富含抗生素的粪便中饲养的无脊椎动物群落的微生物群与在未经处理的粪便中饲养的无脊椎动物群落的微生物群的比较。这项研究填补了我们对以下三个重要生态现象的理解的关键空白：(1)抗生素如何影响土壤微生物和无脊椎动物的群落结构；(2)哪些无脊椎动物和微生物分类群对分解和温室气体排放最重要；(3)无脊椎动物微生物群的破坏如何导致无脊椎动物群落的死亡率。此外，通过在一个农业现场进行我们提出的研究，我们深入了解了是什么控制着一个全球著名的、具有重要经济意义的生态系统的健康和功能。

The discovery of antibiotics was one of the scientific breakthroughs of the 20st century. While many people are familiar with how antibiotics are used for human health, the vast majority of antibiotics produced today are used to promote the health and growth of livestock. As with many medicines, up to 80% of the total dosage of active antibiotics are eliminated through animal waste, like feces and urine, and introduced to the surrounding environment. Although previous research has found more antibiotic-resistant organisms near livestock farms than generally, scientists do not fully understand how antibiotics coming from livestock waste impact important organisms in soils that are exposed to them: soil microbes, like bacteria and fungi, and invertebrates, like millipedes, pillbugs, spiders and insects. Healthy communities of microbes and invertebrates are responsible for recycling nutrients in soils and making them available to plants and the animals that eat them. This research will help scientists understand how the common practice of adding antibiotics to soils, by applying contaminated livestock manure to crop soils, may be disrupting the nutrient-cycling soil organisms, and how well these organisms can make nutrients available. Through this research, scientists, farmers and the public can promote responsible waste management practices that will help protect our ecosystems and benefit human health. The project will also train a graduate student, and American Indian volunteer researchers.Using antibiotic (tetracycline)-laden manure from cattle, this research will consist of a series of field experiments that assess how antibiotic compounds change decomposition rates in the soil, microbial respiration (an important factor in carbon and nutrient cycling), and microbial and invertebrate community composition. The researcher will also test how the microbiome of invertebrate communities raised on antibiotic-laden manure compares to those raised on untreated manure. This research fills a critical gap in our understanding of three important ecological phenomena: (1) how antibiotics affect community structure of soil microbes and invertebrates, (2) which invertebrate and microbial taxa are most important to decomposition and greenhouse gas emission, and (3) how disrupting invertebrate microbiomes drives mortality in invertebrate communities. Furthermore, by conducting our proposed study at an agricultural field site, we provide insight into what governs the health and function of a globally prominent and economically important ecosystem.