Collaborative Research: Algal photosynthetic priming and photolysis as stimulators of ecosystem-level detrital processing by microbial heterotrophs

合作研究：藻类光合启动和光解作用作为微生物异养生物生态系统级碎屑处理的刺激剂

• 批准号: 1456978
• 负责人: Steven Francoeur
• 金额: $ 11.16万
• 依托单位: Eastern Michigan University
• 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: 2015-10-01 至 2019-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1456978&HistoricalAwards=false
• 关键词: Collaborative; Research; Algal; photosynthetic; priming

Freshwater wetlands provide many valuable ecosystem services, including the provision of food and habitat for wildlife, improvement of water quality, flood protection, and defense of lake shorelines from erosion. These attributes make wetlands a significant environmental, recreational, and economic resource for our nation. In freshwater wetlands, tall plants emerging from the water, such as cattails, often account for a large fraction of the plant matter produced. These plants exhibit prolific rates of growth and absorb large amounts of nutrient contaminants, improving water quality in the process. Most of this plant matter is not directly consumed by animals, but instead dies and is decomposed by microorganisms (bacteria and fungi). During decomposition, nutrients trapped within plant tissues may be released via the activity of bacterial and fungal decomposers. Bacteria and fungi growing on decaying plants also serve as a key food resource for many invertebrate animals, and form a link in the flow of energy and nutrients up the food chain (to fish and waterfowl, for example) in wetland habitats. As a consequence, the productivity, nutrient uptake, and decomposition of emergent plants will profoundly affect nearly all aspects of wetland function. This research project will measure the importance of bacteria and fungi in wetland plant decay, and investigate how their potential interactions with algae affect rates of plant matter decomposition and nutrient cycling. Microorganisms are key players in the circulation of nutrients on Earth. This circulation, often referred to as biogeochemical cycling, includes all of the biological, geological and chemical factors that are involved. Understanding the ecology of microorganisms is essential for us to meet the major challenges facing human society, such as conservation and management of natural ecosystems and mitigation of climate change. In addition to training a postdoctoral scholar, this research will train undergraduate and graduate students through a collaborative, multifaceted effort to understand a key ecosystem process, decomposition. Through these efforts researchers will also participate in a series of existing university programs and coordinated outreach activities aimed at recruiting underrepresented groups into the sciences and strengthening science education at the elementary through university levels.The overarching goal of this project is to understand the nature of metabolic interactions among algae, bacteria, and fungi in decomposing plant litter, and to quantify how these interactions influence plant litter decomposition and carbon cycling in wetlands. Photolysis of dissolved and particulate organic matter is widely accepted as an important abiotic decomposition process in aquatic ecosystems. In contrast, enhanced decomposition via algal stimulation of litter-associated heterotrophic microbes has only recently been considered. Prior research by this team has documented rapid metabolic responses of heterotrophic microbes to algal photosynthesis in natural decaying plant litter, thus establishing the potential for algal "priming effects" on microbial-mediated litter decomposition, yet, the relative importance of algal priming and photolysis in facilitating litter decomposition in aquatic ecosystems remains unknown. This project will involve a series of field and laboratory experiments in marsh ecosystems, investigating three key questions centered on photostimulation of litter decomposition: 1) What is the relative importance of algal photosynthetic priming vs. photolysis in facilitating microbial-mediated organic matter decomposition? 2) What is the influence of photolysis and autotroph-heterotroph interactions on ecosystem-scale carbon cycling" 3) What are the mechanisms mediating autotroph-heterotroph interactions in decaying plant litter?

淡水湿地提供许多有价值的生态系统服务，包括提供野生动植物的食物和栖息地，水质的改善，防洪以及避免侵蚀的海岸线防御。这些属性使湿地成为我们国家的重要环境，娱乐和经济资源。在淡水湿地中，从水中出现的高植物（例如香丁）通常占产生的植物物质的很大一部分。这些植物表现出多产的生长速率，并吸收了大量的营养污染物，从而提高了此过程的水质。这种植物的大部分不是动物直接消耗的，而是死亡，而被微生物（细菌和真菌）分解。在分解过程中，可以通过细菌和真菌分解剂的活性释放被困在植物组织中的营养。在腐烂的植物上生长的细菌和真菌也可以作为许多无脊椎动物动物的关键食物资源，并在湿地栖息地中在食物链上（例如鱼类和水禽）形成了能量和营养的联系。结果，新兴植物的生产力，养分摄取和分解将对湿地功能的几乎所有方面产生深远的影响。该研究项目将衡量细菌和真菌在湿地植物腐烂中的重要性，并研究其潜在的与藻类的相互作用如何影响植物质量分解和营养循环的速率。微生物是地球营养素循环中的主要参与者。这种循环通常称为生物地球化学循环，包括所有涉及的生物，地质和化学因子。了解微生物的生态学对于我们应对人类社会面临的主要挑战至关重要，例如自然生态系统的保护和管理和缓解气候变化。除了培训博士后学者外，这项研究还将通过协作，多方面的努力来培训本科生和研究生，以了解关键的生态系统过程，分解。通过这些努力，研究人员还将参与一系列现有的大学课程，并协调宣传活动，旨在招募不足的人群进入科学，并通过大学级别加强小学的科学教育。该项目的总体目标是了解这些项目的代谢互动的性质湿地。 溶解和颗粒有机物的光解被广泛认为是水生生态系统中重要的非生物分解过程。相比之下，直到最近才考虑通过垃圾相关的异养微生物来增强分解。该团队的先前研究已经记录了异育型微生物对自然腐烂植物垃圾中藻类光合作用的快速代谢反应，从而确立了藻类对微生物介导的垃圾分解的潜在“启动启动”的潜力，但是，Algal启动和光溶解的相对重要性在促进litter litter litter litter decomportics in Aquosystots in Aquosystots中的相对重要性仍然存在。该项目将涉及沼泽生态系统中的一系列现场和实验室实验，研究以窝点分解的光刺激为中心的三个关键问题：1）藻类光合作用启动与光解相对于促进微生物介导的有机物分解的相对重要性？ 2）光解和自养生型相互作用对生态系统尺度碳循环的影响是什么：“ 3）在衰减植物垃圾中介导自养生型核能相互作用的机制是什么？