DISSERTATION RESEARCH: Dynamics of labile organic matter fractions in arctic soils

论文研究：北极土壤中不稳定有机物组分的动态

• 批准号: 0909747
• 负责人: John Moore
• 金额: $ 1.32万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909747&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Dynamics; labile; organic

The proposed doctoral dissertation research will determine the extent to which soil aggregates, a foundation of soils, provide stabilization for soil organic matter (SOM) in the Arctic. Warming has been linked to changes in carbon cycling in the Arctic. Cold temperatures and anoxic conditions inhibit microbial activity and reduce decomposition, resulting in an accumulation of carbon-rich organic matter, straining an already nitrogen-limited system. Nutrient additions have changed the plant community and depleted soil carbon; however, mechanisms behind carbon loss are not understood. It is not known which OM fractions are most susceptible to degradation in Arctic soils, and 2) where are they located within the soil matrix. These factors are important to understanding mechanisms behind carbon loss in Arctic soils, which may be due, in part, to shifts in the physical stability of soil aggregates. In other words, soils with greater proportions of macroaggregates contain more carbon.Soils have been collected from long-term nutrient addition experiments at the Arctic LTER site on the Alaskan North Slope, and were separated into four size classes of aggregates. These aggregates will be separated into sub-structural elements as well as free OM, which will reveal if SOM is protected within aggregates and which fractions are susceptible to degradation. The project will also link current conceptual models of soil carbon stabilization to the Arctic. The graduate student will interact with the K-12 community by providing research opportunities for teachers through existing workshops, internships, and a Teacher-in-Residence program.

拟议的博士论文研究将确定在何种程度上土壤团聚体，土壤的基础，提供稳定的土壤有机质（SOM）在北极。 气候变暖与北极碳循环的变化有关。低温和缺氧条件抑制微生物活性，减少分解，导致富碳有机物的积累，使本已氮有限的系统紧张。养分的增加改变了植物群落，消耗了土壤碳;然而，碳损失背后的机制尚不清楚。目前尚不清楚哪些有机质组分在北极土壤中最容易降解，以及2）它们在土壤基质中的位置。这些因素对于了解北极土壤碳损失背后的机制非常重要，这可能部分是由于土壤团聚体物理稳定性的变化。 换句话说，大团聚体比例较大的土壤含有更多的carbon.Soils已经收集了长期的营养添加实验在北极LTER网站在阿拉斯加北坡，并分为四个大小类的团聚体。 这些聚集体将被分离成子结构元素以及游离OM，这将揭示SOM是否在聚集体内受到保护以及哪些部分容易降解。该项目还将把目前土壤碳稳定化的概念模型与北极联系起来。研究生将与K-12社区互动，通过现有的研讨会，实习和教师驻校计划为教师提供研究机会。