Large seasonal changes in Q10 of soil respiration in a beech forest
Large seasonal changes in Q10 of soil respiration in a beech forest
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DOI：
10.1046/j.1365-2486.2003.00636.x
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发表时间：
2003-06-01
影响因子：
11.6
通讯作者：
Pilegaard, K
中科院分区：
文献类型：
--
作者：
Janssens, IA;Pilegaard, K
我们分析了一年的连续土壤呼吸测量数据，以评估丹麦山毛榉林中土壤呼吸对温度敏感性的变化。从全年所有测量数据得出的单一温度函数（Q₁₀ = 4.2）足以估算全年土壤呼吸总量及其季节变化。然而，从每周数据集得出的Q₁₀值在夏季（平均土壤温度为14℃时）为3，在冬季（2℃时）为23，这表明年度温度函数低估了冬季土壤呼吸的天气变化。这些结果强调，经验模型的参数化应采用与模型输出所需相似的时间分辨率。如果模型的目的是模拟全年土壤呼吸速率，年度参数化就足够了。然而，如果需要模拟从几天到几周的时间段内的土壤呼吸，就像在天气形势下将土壤呼吸与生态系统总呼吸进行比较时那样，就需要更短期的参数化。尽管冬季的Q₁₀值较高，但冬季土壤呼吸对温度的绝对响应比夏季小。这主要是因为从绝对值来看，土壤呼吸的温度敏感性不仅取决于Q₁₀，还取决于土壤呼吸速率，而冬季土壤呼吸速率大幅降低。尽管如此，冬季土壤呼吸的Q₁₀值大于仅由呼吸速率降低所能解释的程度。由于Q₁₀的季节变化与温度呈负相关，与土壤湿度呈正相关，它们也可能与温度和/或土壤湿度条件的变化有关。
We analyzed one year of continuous soil respiration measurements to assess variations in the temperature sensitivity of soil respiration at a Danish beech forest. A single temperature function derived from all measurements across the year (Q(10) = 4.2) was adequate for estimating the total annual soil respiration and its seasonal evolution. However, Q(10)'s derived from weekly datasets ranged between three in summer (at a mean soil temperature of 14degreesC) and 23 in winter (at 2degreesC), indicating that the annual temperature function underestimated the synoptic variations in soil respiration during winter. These results highlight that empirical models should be parameterized at a time resolution similar to that required by the output of the model. If the objective of the model is to simulate the total annual soil respiration rate, annual parameterization suffices. If however, soil respiration needs to be simulated over time periods from days to weeks, as is the case when soil respiration is compared to total ecosystem respiration during synoptic weather patterns, more short-term parameterization is required.Despite the higher wintertime Q(10)'s, the absolute response of soil respiration to temperature was smaller in winter than in summer. This is mainly because in absolute numbers, the temperature sensitivity of soil respiration depends not only on Q(10), but also on the rate of soil respiration, which is highly reduced in winter. Nonetheless, the Q(10) of soil respiration in winter was larger than can be explained by the decreasing respiration rate only. Because the seasonal changes in Q(10) were negatively correlated with temperature and positively correlated with soil moisture, they could also be related to changing temperature and/or soil moisture conditions.