How Ingested Soil Microbes Stimulate Greenhouse Gas Emissions and Iron Transformations of Earthworms

土壤排放的一氧化二氮(N2O)约有50%可能来自蚯蚓，蚯蚓是一种摄取土壤微生物群落的土壤大型动物。在上一个资助期，在摄取的反硝化菌和蚯蚓排放N2O和氮素(N2)之间建立了协同关系。新的目标(摘要形式)是：确定蚯蚓是否释放一氧化氮(NO)；确定与肠道中C和N转化相关的摄食微生物群落结构和功能变化的调控参数(分子、微传感器和报告菌株技术；聚合酶链式反应辅助分离目标生物)；将蚯蚓丰度与田间N2O和NO排放相关联；确定蚯蚓生态型是否影响铸模和与洞穴相关的土壤(蠕虫土室、微传感器)中硝酸盐、N2O和O2的原位梯度；评估南半球和北半球蠕虫的N2O排放，并评估与这些排放相关的微生物(功能基因指纹图谱)。这项研究将解决碳和氮驱动的微生物过程之间的主要联系，这些微生物过程在蚯蚓肠道中产生含氮气体。

Up to approximately 50% of soil-emitted nitrous oxide (N2O) might be derived from earthworms, a soil macrofauna that ingests soil microbial biomes. In the previous funding period, synergistic links were established between ingested denitrifiers and the emission of N2O and dinitrogen (N2) by earthworms. The new objectives (in abstracted form) are: to determine if earthworms emit nitric oxide (NO); to identify regulatory parameters responsible for changes in the structure and function of ingested microbial biomes associated with C- and N-transformations in the gut (molecular, microsensor, and reporter strain technologies; PCR-assisted isolation of target organisms); to correlate earthworm abundances with N2O and NO emissions in the field; to determine if earthworm ecotypes affect in situ gradients of nitrate, N2O, and O2 in casts and burrow-associated soils (wormsoil chambers, microsensors); to assess N2O emissions of worms from southern and northern hemispheres, and evaluate the microbes associated with these emissions (functional gene fingerprinting). This study will resolve primary links between C- and N-driven microbial processes that yield nitrogenous gases in the earthworm gut.