Nutrient Cycling in Response to Forest Growth at Elevated CO2 (FACE)

Deb-9815350 Schlesinger/Finzi在过去的200年里，大气中二氧化碳的浓度从280ppm增加到360ppm，并将在下个世纪翻一番。随着[CO2]a的增加，森林生产力的增加(因此树木生物量中的碳贮量)预计会增加。森林生产力的增加可能会受到土壤氮(N)和磷(P)有效性的限制。我们将通过在杜克森林自由空气二氧化碳增肥(FACE)下生长的封闭式林冠森林来研究森林生产力和养分循环之间的关系，以响应二氧化碳施肥。为了测试养分是否会在高二氧化碳浓度下限制森林的生长，我们将测量：(1)土壤中的N和P通量(微生物动力学，N和P的有效性)；(2)树木对N和P的吸收；以及(3)对N和P从植被到土壤流动的主要控制。

DEB-9815350 Schlesinger/Finzi The atmospheric concentration of CO2 (abbreviated [CO2]a) has increased from 280 ppm to 360 ppm during the past 200 years and will double during the next century. Increases in forest productivity (and hence C-storage in tree biomass) are anticipated with the increase in [CO2]a. The increase in forest productivity will likely be limited by the availability of soil nitrogen (N) and phosphorus (P). We will examine the relationships between forest productivity and nutrient cycling in response to CO2 fertilization by working in a closed-canopy forest growing under Free-Air CO2 Enrichment (FACE) in the Duke Forest. To test whether nutrients will limit the growth of forests under elevated [CO2]a we will measure: (1) N & P fluxes in soils (microbial dynamics, N & P availability); (2) N & P uptake by trees; and (3) the major controls over the flux of N & P from vegetation to soils.