Dissimilatory and Assimilatory Controls on Nitrogen Retention and Loss: Oxygen and Nitrate Dynamics in Tropical Forest Soils

[摘要]银的异化和同化作用对氮的保留和损失的控制：热带森林土壤中氧和硝酸盐的动态变化在潮湿的热带森林中，丰富的降雨量、高保水能力的土壤和高代谢活性的结合可以导致氧气在土壤中迅速和完全消耗的条件。这些条件也增加了氮微量气体损失和浸出的可能性。在全球范围内，热带森林目前的一氧化二氮排放量最高，与温带森林相比，地下水中氮的损失可能更大。尽管氮流失的可能性很大，但热带森林植物的生产力通常不受氮的限制。西尔弗博士和他的同事们建议将实地和实验室实验结合起来，研究波多黎各森林中的氮保留（通过异化硝酸盐还原为铵，以及植物和微生物的吸收）和氮损失（通过淋滤和反硝化）。该研究将有助于我们进一步了解湿润热带森林氮动态的控制机制，并提高我们预测人为氮沉降和全球变化对氮循环的影响的能力

Abstract00-89783SilverDissimilatory and assimilatory controls on nitrogen retention and loss: Oxygen and nitrate dynamics in tropical forest soilsIn humid tropical forests, the combination of abundant rainfall, soils with high water-holding capacity, and high metabolic activity can lead to conditions where oxygen is rapidly and completely consumed in the soil. These conditions also increase the potential for nitrogen trace gas loss and leaching. In a global context, tropical forests currently have the highest N2O emissions, and can exhibit large nitrogen losses to groundwater relative to temperate forests. Despite this high potential for nitrogen loss, tropical forest plant productivity is not generally nitrogen limited. Dr. Silver and colleagues propose to combine field and laboratory experiments to study nitrogen retention (via dissimilatory nitrate reduction to ammonium, and plant and microbial uptake) and nitrogen loss (via leaching and denitrification) in forests of Puerto Rico. This research will contribute to our understanding of the mechanisms controlling nitrogen dynamics in humid tropical forests, and improve our ability to predict the effects of anthropogenic nitrogen deposition and global change on nitrogen cycling