LiT: Microbial control on soil C and N cycling during forest recovery: Linking ecosystem processes with microbial function

土壤中的微生物调节着重要的陆地生态系统过程，如植物生产力、养分有效性、土壤碳固存和温室气体产生。许多研究都集中在全球变化对植物多样性和养分循环的影响上，而对驱动许多生态和生物地球化学过程的细菌和真菌的关注较少。将土壤微生物群落组成与功能联系起来，了解它们对土地利用和土地覆盖变化的响应，对于维持生态系统生产力和预测未来干扰的影响具有重要意义。本研究将结合新的基因组技术、生物标志物分析和微生物活性测量，以确定土壤微生物功能多样性和活性与土壤有机质循环之间的关系。研究人员将在波多黎各原牧场上生长的一系列不同年龄的次生林地点进行这项研究。土壤碳、森林结构、生物量和树种组成的变化已经得到了描述。本研究将重点研究土壤微生物群落在碳循环中的作用及其对生态系统恢复的响应。基因组学的进步正以非常快的速度增加我们对土壤中微生物巨大多样性的认识，但需要更多的工作来将微生物身份与生态过程联系起来。碳交易市场和生态系统服务支付的出现使全球的注意力集中在森林碳封存上。然而，土壤碳库仍无法预测。这个池可以是地上植物生物量的两倍大，将对植被的变化做出反应。更好地了解微生物功能多样性在森林恢复过程中如何变化，以及这如何影响土壤中的有机质保留或流失，可以改善维持生态系统生产力和恢复退化地点土壤肥力的努力。这项研究的结果将被纳入现有的生物地理学、生物地球化学和微生物生态学课程。调查人员积极参与威斯康星大学的教育和指导活动，以及增加包括妇女在内的代表性不足的少数民族参与环境科学的外部项目。将为威斯康辛州和波多黎各拥有不同学生群体的当地学校编写关于热带生态学、微生物学和全球变化的英语和西班牙语演讲。

Microorganisms in soils regulate important terrestrial ecosystem processes, such as plant productivity, nutrient availability, soil carbon sequestration, and greenhouse gas production. Much research has focused on global change impacts on plant diversity and nutrient cycling, with less attention on the bacteria and fungi that drive many ecological and biogeochemical processes. Linking soil microbial community composition with function, and understanding their response to changes in land use and land cover is important for sustaining ecosystem productivity and for predicting the impact of future disturbances. This research will combine novel genomic technologies, biomarker analyses, and measurements of microbial activity to identify relationships between soil microbial functional diversity and activity and soil organic matter cycling. The investigators will conduct this research in a well-replicated series of secondary forest sites of different ages growing on former pastures in Puerto Rico. Changes in soil carbon, forest structure, biomass, and tree species composition have already been described. This research will focus on the role of soil microbial communities in carbon cycling and their response to ecosystem recovery. Advances in genomics are increasing our knowledge about the vast diversity of microorganisms in soils at a very fast pace, but more work is needed to link microorganism identity with ecological processes. The emergence of carbon trading markets and payments for ecosystem services has focused global attention on forest carbon sequestration. However, the soil carbon pool is still unable to be predicted. This pool, which can be twice as large as that in aboveground plant biomass, will respond to changes in vegetation. A better understanding of how microbial functional diversity changes during forest recovery, and how this affects organic matter retention or loss from soils, can improve efforts to maintain ecosystem productivity and restore soil fertility to degraded sites. Findings from this research will be incorporated into existing courses on biogeography, biogeochemistry, and microbial ecology. The investigators are actively engaged in education and mentoring activities at the University of Wisconsin, and in external programs for increasing the participation of underrepresented minorities, including women, in the environmental sciences. Presentations in English and Spanish will be developed on tropical ecology, microbiology, and global change for local schools with diverse student bodies in Wisconsin and in Puerto Rico.