Effects of elevated atmospheric CO2 and tropospheric O3 on nutrient dynamics:: decomposition of leaf litter in trembling aspen and paper birch communities
Effects of elevated atmospheric CO2 and tropospheric O3 on nutrient dynamics:: decomposition of leaf litter in trembling aspen and paper birch communities
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DOI：
10.1007/s11104-007-9361-y
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发表时间：
2007-10-01
期刊：
影响因子：
4.9
通讯作者：
Giardina, Christian P.
中科院分区：
文献类型：
--
作者：
Liu, Lingli;King, John S.;Giardina, Christian P.
大气变化可通过改变养分循环，对陆地生态系统的功能产生重大影响。我们研究了如何动态的养分释放落叶响应两个重要的大气变化：大气CO2和对流层O-3上升。我们评估了这些气体对白杨（胡杨Michx）和桦树（白桦沼泽）/白杨社区在莱因兰德，WI的白杨FACE项目的落叶养分动态的独立和综合影响。将自然衰老的落叶在田间的落叶袋中培养735天。在孵化过程中，分解凋落物取样6次，并分析了碳，宏观（N，P，K，S，Ca和Mg）和微观（Mn，B，Zn和Cu）营养浓度。CO2浓度升高显著降低了N（-10.7%）和B（-14.4%）的初始凋落物浓度，增加了K（+23.7%）和P（+19.7%）的初始凋落物浓度，而其他元素的初始凋落物浓度没有变化。O-3浓度升高显著降低了P（-11.2%）、S（-8.1%）、Ca（-12.1%）和Zn（-19.5%）的初始凋落物浓度，而其他元素没有变化。将浓度数据与凋落物数据配对，我们估计CO2浓度升高显著增加了所有营养素的土壤通量：N（+12.5%），P（+61.0%），K（+67.1%），S（+28.0%），Mg（+40.7%），Ca（+44.0%），Cu（+38.9%），Mn（+62.8%）和Zn（+33.1%）。升高的O-3具有相反的影响：N（-22.4%）、P（-25.4%）、K（-27.2%）、S（-23.6%）、Ca（-27.6%）、Mg（-21.7%）、B（-16.2%）、Cu（-20.8%）和Zn（-31.6%）。9种元素在培养过程中的相对释放速率为：K >= P >= mass >= Mg >= B >= Ca >= S >= N >= Mn >= Cu >= Zn。大气变化对养分释放速率的影响不大，除了在CO2浓度升高下降低Ca和B的释放，在O-3浓度升高下降低N和Ca的释放。我们的结论是，升高的CO2和升高的O-3将改变养分循环更多地通过对凋落物产生的影响，而不是凋落物养分浓度或释放速率。
Atmospheric changes could strongly influence how terrestrial ecosystems function by altering nutrient cycling. We examined how the dynamics of nutrient release from leaf litter responded to two important atmospheric changes: rising atmospheric CO2 and tropospheric O-3. We evaluated the independent and combined effects of these gases on foliar litter nutrient dynamics in aspen (Populus tremuloides Michx) and birch (Betula papyrifera Marsh)/aspen communities at the Aspen FACE Project in Rhinelander, WI. Naturally senesced leaf litter was incubated in litter bags in the field for 735 days. Decomposing litter was sampled six times during incubation and was analyzed for carbon, and both macro (N, P, K, S, Ca, and Mg) and micro (Mn, B, Zn and Cu) nutrient concentrations. Elevated CO2 significantly decreased the initial litter concentrations of N (-10.7%) and B (-14.4%), and increased the concentrations of K (+23.7%) and P (+19.7%), with no change in the other elements. Elevated O-3 significantly decreased the initial litter concentrations of P (-11.2%), S (-8.1%), Ca (-12.1%), and Zn (-19.5%), with no change in the other elements. Pairing concentration data with litterfall data, we estimated that elevated CO2 significantly increased the fluxes to soil of all nutrients: N (+12.5%), P (+61.0%), K (+67.1%), S (+28.0%), and Mg (+40.7%), Ca (+44.0%), Cu (+38.9%), Mn (+62.8%), and Zn (+33.1%). Elevated O-3 had the opposite effect: N (-22.4%), P (-25.4%), K (-27.2%), S (-23.6%), Ca (-27.6%), Mg (-21.7%), B (-16.2%), Cu (-20.8%), and Zn (-31.6%). The relative release rates of the nine elements during the incubation was: K >= P >= mass >= Mg >= B >= Ca >= S >= N >= Mn >= Cu >= Zn. Atmospheric changes had little effect on nutrient release rates, except for decreasing Ca and B release under elevated CO2 and decreasing N and Ca release under elevated O-3. We conclude that elevated CO2 and elevated O-3 will alter nutrient cycling more through effects on litter production, rather than litter nutrient concentrations or release rates.