Interactive effects of CO2, soil temperature, moisture and nutrients on black spruce ecophysiology

自工业革命以来，大气二氧化碳浓度([CO2])一直在迅速增加，而且在可预见的未来还将继续增加。不断上升的[二氧化碳]将影响植物和生态系统的生理、生长和分布。最近的研究表明，与大气[二氧化碳]增加相关的气候变化将在北方地区最为突出。北方森林是地球上最大的陆地生态系统。它的生态生理活动可以对地球表面的环境条件产生深远的影响。例如，它的光合作用是固定大气二氧化碳和生产氧气的重要力量。从北方森林到大气的水分通量的生态生理调节对低层大气的性质有重要影响。这些生态生理过程又受气候条件的控制。黑云杉是北方森林中最丰富的树种，它对上升的[CO2]的反应将对北方森林对全球气候变化的整体反应产生重大影响。黑云杉生长在广泛的土壤温度、水分和营养条件下。土壤条件可能会影响物种对[CO2]上升的生态生理反应。然而，我们对这些影响的了解非常有限。本研究将进行一系列对照实验，研究在当前和未来大气CO2浓度下，土壤温度、水分和营养如何相互作用，影响黑云杉的生态生理活动。将开发描述这些反应的计算机模型。这些模型将在生态系统模型中提供树木生理模型和土壤模型之间的关键联系，以研究北方森林对全球气候变化的反应。

The atmospheric carbon dioxide concentration ([CO2]) has been increasing rapidly since the Industrial Revolution and the increase will continue in the foreseeable future. The rising [CO2] will affect the physiology, growth and distribution of plants and ecosystems. Recent studies suggest that the climate change associated with increasing atmospheric [CO2] will be the most prominent in the boreal region. The boreal forest is the largest terrestrial ecosystem on the earth. Its ecophysiological activities can have a profound impact on the environmental conditions of the earth's surface. For example, its photosynthesis is a significant force in the fixation of atmospheric CO2 and the production of oxygen. The ecophysiological regulation of water flux from the boreal forest to the atmosphere has a major influence on the properties of the lower atmosphere. The ecophysiological processes are in turn controlled by climate conditions. Black spruce is the most abundant tree species in the boreal forest and its response to the rising [CO2] will exert a major influence to the overall response of the boreal forest to global climate change. Black spruce grows over a wide range of soil temperature, moisture and nutrient conditions. The soil conditions will likely influence the ecophysiological responses of the species to rising [CO2]. However, our understanding of these effects is very limited. This research will conduct a series of controlled experiments to examine how soil temperature, moisture and nutrition interact with each other in influencing the ecophysiological activities of black spruce under current and future atmospheric CO2 concentration. Computer models will be developed describing the responses. These models will provide a critical linkage between tree physiology models and soil models within ecosystem models for studying the response of boreal forests to the global climate change.