Linking DOC and DON Fluxes to Soil Properties at Watershed and Landscape Scales

PI最近的工作表明，在全球范围内，土壤碳氮比（C:N）是地表径流中溶解有机碳（DOC）损失的一个非常有力的预测指标。如果这种关系在流域和景观尺度上成立，那么土壤C:N将为预测和模拟DOC通量的变化提供一个有力的工具。在这个项目中，pi将研究波多黎各潮湿热带森林、新罕布什尔州北部混交林和苏格兰荒原中土壤特性和DOC通量之间关系的本质。本研究探讨了土壤D:N在预测三个生态系统内DOC通量变异性方面的价值，并探讨了一些潜在的物理和生物机制，这些机制可能负责全球尺度上DOC通量与土壤C:N之间的联系。该研究将包括经验和模型组成部分，预计将更好地了解热带和温带地区DOC损失的调节机制。这项工作的更广泛含义涉及流域管理，因为溶解的有机碳和氮对地表水质量有重要影响。微量金属的溶解度、饮用水中三卤甲烷的形成以及农药的运输都与DOC水平有关。

Recent work by the PI's shows that at a global scale, soil carbon:nitrogen (C:N) is a very strong predictor of dissolved organic carbon (DOC) losses in surface runoff. If this relationship holds at the watershed and landscape scale, then soil C:N would provide a powerful tool for predicting and modeling changes in DOC flux. In this project, the PIs will examine the nature of the relationship between soil properties and DOC flux in wet tropical forests of Puerto Rico, the northern mixed forests of New Hampshire and a heath/moorland in Scotland. The proposed research examines the value of soil D:N in predicting variability in DOC flux within the three ecosystems, and also examines some of the underlying physical and biological mechanisms which may be responsible for the linkage between DOC flux and soil C:N recently documented at the global scale. The research will include empirical and modeling components and is expected to result in a better understanding of the mechanisms regulating DOC losses in tropical and temperate sites. The broader implications of this work relate to watershed management in that dissolved organic carbon and nitrogen have important effects on surface water quality. Trace metal solubility, formation of trihalomethanes in drinking water supplies, and pesticide transport are all linked to DOC levels.