Temporal Dynamics in Soil Oxygen and Greenhouse Gases in Two Humid Tropical Forests
Temporal Dynamics in Soil Oxygen and Greenhouse Gases in Two Humid Tropical Forests
复制标题
DOI：
10.1007/s10021-010-9402-x
复制
发表时间：
2011-03-01
期刊：
影响因子：
3.7
通讯作者：
Detto, Matteo
中科院分区：
文献类型：
--
作者：
Liptzin, Daniel;Silver, Whendee L.;Detto, Matteo
土壤氧化还原在调节陆地生态系统中的生物地球化学转化中起着关键作用，但对生态系统内部和跨生态系统中氧化还原的时间和空间模式以及相关的控制机制知之甚少。旱地湿润的热带森林土壤可能特别容易发生波动的氧化还原，因为充足的降雨限制了氧气(O-2)通过质地细腻的土壤的扩散，而高生物活性增加了O-2的消耗。我们使用配备了自动传感器的土壤平衡箱来确定两个不同气候条件下湿润热带森林中土壤氧浓度的时间变异性。我们还测量了土壤痕量气体(CO2、N2O和CH4)作为氧化还原敏感的生物地球化学指标。平均而言，高海拔云雾林的O-2浓度(3.0+/-A0.8%)显著低于低海拔湿润热带森林(7.9+/-A1.1%)。土壤O-2是动态的，特别是在湿润的热带森林中，其浓度在一天内变化高达10%。该站位O-2时间序列的周期性最强，间隔为16天，且与每小时降水量有关。不同地点的温室气体浓度差异很大，但与土壤O-2的关系是一致的：O-2与CO2和CH4呈负相关，与N2O呈正相关。这些结果首次量化了湿润热带森林土壤氧化还原的时空变异性，并表明降水的时序在数小时到数周的尺度上对生物地球化学循环起着重要作用。
Soil redox plays a key role in regulating biogeochemical transformations in terrestrial ecosystems, but the temporal and spatial patterns in redox and associated controls within and across ecosystems are poorly understood. Upland humid tropical forest soils may be particularly prone to fluctuating redox as abundant rainfall limits oxygen (O-2) diffusion through finely textured soils and high biological activity enhances O-2 consumption. We used soil equilibration chambers equipped with automated sensors to determine the temporal variability in soil oxygen concentrations in two humid tropical forests with different climate regimes. We also measured soil trace gases (CO2, N2O, and CH4) as indices of redox-sensitive biogeochemistry. On average, the upper elevation cloud forest had significantly lower O-2 concentrations (3.0 +/- A 0.8%) compared to the lower elevation wet tropical forest (7.9 +/- A 1.1%). Soil O-2 was dynamic, especially in the wet tropical forest, where concentrations changed as much as 10% in a single day. The periodicity in the O-2 time series at this site was strongest at 16 day intervals and was associated with the hourly precipitation. Greenhouse gas concentrations differed significantly between sites, but the relationships with soil O-2 were consistent: O-2 was negatively related to both CO2 and CH4 and positively related to N2O. These results are among the first to quantify the temporal and spatial scale of variability in soil redox in humid tropical forests, and show that the timing of precipitation plays a strong role in biogeochemical cycling on the scale of hours to weeks.