TECO: Collaborative Research: The Jasper Ridge Global Change Experiment: Ecosystem-scale Responses to Elevated CO2 Warming, Nutrient Deposition, and Increased Moisture Inputs

Mooney 9727060未来几十年的全球变化几乎可以肯定是多因素的，大气中二氧化碳、温度、氮沉降和降水量的水平都会发生变化。迄今为止，没有实验研究解决这一整套相互作用的全球变化领域。尽管对这些因素之间相互作用的性质缺乏共识，但解释和预测的基础主要是建立在对自然模式的观察和单因素实验的数据上。虽然这些方法至少在原则上可以获得一整套潜在的重要机制，但单因素实验和沿着自然梯度的观察并不能为评估我们预测几个同时运行的机制的后果的能力提供背景。 为了解决这一信息的缺乏，该项目将使用实地实验，改变二氧化碳，温度，水投入和氮投入的因子组合。集中在四个综合响应变量-初级生产力，土壤碳储量，土壤养分的可用性，物种或功能组组成-这项研究将测试零假设，即对变暖和CO2浓度升高的组合反应基本上是加性的，对单个因素的反应之和。实验将采用迷你FACE和红外加热器技术在加州一年生草地，在那里它是可行的，执行一个设计结合几代的优势生物，一系列的治疗，合理的复制。为了便于与模型输出进行比较，将使用三个CO2水平和三个温度水平的实验。

Mooney 9727060 Global changes over the coming decades are almost certain to be multi-factorial, with altered levels of atmospheric CO2, temperature, nitrogen deposition, and precipitation. To date, no experimental studies address this full suite of interacting global changes in the field. Despite a profound lack of consensus on the nature of the interactions among these factors, the foundation for interpretation and prediction is built largely from observations on natural patterns and data from single-factor experiments. While these can, at least in principle, yield access to the full suite of potentially important mechanisms, single-factor experiments and observations along natural gradients do not provide a context for evaluating our ability to predict the consequences of several, simultaneously operating mechanisms. To address this lack of information, this project will use field experiments with a factorial combination of altered CO2, temperature, water inputs, and nitrogen inputs. Focusing on four integrated response variables - primary production, soil carbon storage, soil nutrient availability, and species or functional group composition - this research will test the null hypothesis that responses to warming and elevated CO2 in combination are essentially additive, the sum of the responses to the individual factors. The experiments will employ mini-FACE and infrared heater technology in a California annual grassland, where it is feasible to execute a design combining several generations of the dominant organisms, a range of treatments, and reasonable replication. To facilitate the comparison with model output, experiments with three levels of CO2 and three levels of temperature will be used.