Forest-atmosphere carbon dioxide exchange in eastern Siberia
Forest-atmosphere carbon dioxide exchange in eastern Siberia
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DOI：
10.1016/s0168-1923(98)00057-4
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发表时间：
1998-04-30
影响因子：
6.2
通讯作者：
Vygodskaya, NN
中科院分区：
文献类型：
--
作者：
Hollinger, DY;Kelliher, FM;Vygodskaya, NN
我们调查了未受干扰的落叶松 (Larix gmelinii (Rupr.) Rupr) 之间每日的二氧化碳交换情况。 1993 年 7 月和 8 月期间西伯利亚偏远地点的森林和大气。我们的目标是通过测量森林和林下涡流和储存通量来测量总二氧化碳交换并将其划分为地上和地下部分，然后确定环境因素与生态系统代谢观察结果之间的关系。与其他地方的森林相比，森林生态系统的最大净CO2吸收量极低，仅在上午晚些时候达到峰值，约为5 mu mol m(-2) s(-1)。生态系统 CO2 净吸收量随着光合活性光子通量密度 (PPFD) 的增加而增加，并随着大气水汽饱和度 (D) 的增加而减少。白天生态系统的二氧化碳吸收量在雨后立即增加，并在大约六天的干旱后急剧下降。夜间生态系统呼吸量平均约为 2.4 mu mol m-2 s(-1)，其中约 40% 来自森林地面（根和异养生物）。林下涡流与 5 cm 土壤温度之间的关系遵循阿累尼乌斯模型，随温度呈指数增长（Q(10) 类似于 2.3），因此在炎热的夏季午后，生态系统成为 CO2 的来源。树冠CO？交换计算为冠层上方和下方涡流之间的差异。对于高于 500 μmol m-2 s(-1) 的 PPFD，冠层吸收在类似于 6 μmol CO2 m-2 s(-1) 时饱和，并随着 D 的增加而降低。Makela 等人的最佳气孔控制模型。 (1996) 被用作“大叶”冠层模型，其参数值由非线性最小二乘法确定。该模型准确模拟了森林对光照、饱和度不足和干旱的反应。该模型的精度使得建模和测量的森林交换之间的残差的每日模式再现了组成存储通量。该模型和独立的叶水平测量表明，与其他北方森林相比，落叶松植物碳增益的边际水成本与落叶树或沙漠树种的值更相似。夏季中期，L. gmelinii 森林生态系统通常是 CO2 的净汇，储存量约为 0.75 g C m(-2) d(-1)。由 Elsevier Science B.V. 出版
We investigated the daily exchange of CO2 between undisturbed Larix gmelinii (Rupr.) Rupr. forest and the atmosphere at a remote Siberian site during July and August of 1993. Our goal was to measure and partition total CO2 exchanges into aboveground and belowground components by measuring forest and understory eddy and storage fluxes and then to determine the relationships between the environmental factors and these observations of ecosystem metabolism. Maximum net CO2 uptake of the forest ecosystem was extremely low compared to the forests elsewhere, reaching a peak of only similar to 5 mu mol m(-2) s(-1) late in the morning. Net ecosystem CO2 uptake increased with increasing photosynthetically active photon flux density (PPFD) and decreased as the atmospheric water vapor saturation deficit (D) increased. Daytime ecosystem CO2 uptake increased immediately after rain and declined sharply after about six days of drought. Ecosystem respiration at night averaged similar to 2.4 mu mol m-2 s(-1) with about 40% of this coming from the forest floor (roots and heterotrophs). The relationship between the understory eddy flux and soil temperature at 5 cm followed an Arrhenius model, increasing exponentially with temperature (Q(10)similar to 2.3) so that on hot summer afternoons the ecosystem became a source of CO2. Tree canopy CO? exchange was calculated as the difference between above and below canopy eddy flux. Canopy uptake saturated at similar to 6 mu mol CO2 m-2 s(-1) for a PPFD above 500 mu mol m-2 s(-1) and decreased with increasing D. The optimal stomatal control model of Makela et al. (1996) was used as a 'big leaf' canopy model with parameter values determined by the non-linear least squares. The model accurately simulated the response of the forest to light, saturation deficit and drought. The precision of the model was such that the daily pattern of residuals between modeled and measured forest exchange reproduced the component storage flux. The model and independent leaf-level measurements suggest that the marginal water cost of plant C gain in Larix gmelinii is more similar to values from deciduous or desert species than other boreal forests. During the middle of the summer, the L. gmelinii forest ecosystem is generally a net sink for CO2, storing similar to 0.75 g C m(-2) d(-1). Published by Elsevier Science B.V.