Upland tundra in the foothills of the Brooks Range, Alaska, U.S.A.: lichen long-term photosynthetic CO2 uptake and net carbon gain
Upland tundra in the foothills of the Brooks Range, Alaska, U.S.A.: lichen long-term photosynthetic CO2 uptake and net carbon gain
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美国阿拉斯加州布鲁克斯山脉山麓的高地苔原：地衣长期光合作用二氧化碳吸收和净碳增益
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
J. Tenhunen
中科院分区：
文献类型：
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作者：
O. Lange;S. Hahn;A. Meyer;J. Tenhunen
对碳增益的估计是基于先前发表的7种地衣物种在其自然苔原栖息地的二氧化碳交换过程的测量结果的综合得出的。计算了总净光合CO2吸收、CO、暗呼吸损失以及两者之间的平衡。在1988年和1989年7月至9月的生长期中，对地衣样品进行了26 d的146次观测，并将其分为5类天气条件。根据气象资料，建立了这些天气类型在生长季节的发生规律。将这些数据集结合起来，就可以估计出季节性的碳增益。综合光合碳吸收量最高的蓝藻为malacea Peltigera，是arctylina的1.5倍，是产量最低的Masonhalea richardsonii的5倍，两者都是绿藻。不同物种间碳吸收总量与短期最大净光合速率基本呈线性相关，说明光合能力对碳吸收的重要性。所有物种的平均呼吸碳损失约为33%。在季节碳平衡方面，确定了3组物种：高产种（碳收益占菌体碳含量的24.0 ~ 21.5%），包括北极蒿、马来蒿、灰齿蒿和毛茛，低高产种为理查松（6.8%），中等高产种为白头翁（15.9%）和高山树（14.6%）。季节碳增益与最大可能菌体生长有关。在典型冻土带群落中，地衣生物量的年增长量估计为47.2 gDW - m-2
Estimates of carbon gain were obtained based upon integration of previously published measurements of diel courses of CO2 exchange of seven lichen species in their natural tundra habitat. Total net photosynthetic CO2 uptake, CO, loss by dark respiration, and the balance between these were calculated. The field measurements (146 observations of lichen sample diel courses on 26 d distributed over the growth periods from July through September in 1988 and 1989) were classed with respect to 5 types of weather conditions. The occurrence of these weather types during the growing season was established according to meteorological data. Combination of these data sets permits an estimate of seasonal carbon gain. Integrated photosynthetic carbon uptake was highest for the cyanobacterial Peltigera malacea, 1.5 times higher than for Dactylina arctica and 5 times higher than for the least productive Masonhalea richardsonii, both being green algal species. There was an essentially linear correlation across species between the sum of carbon uptake and short-term maximal rates of net photosynthesis, stressing the importance of photosynthetic capacity for carbon gain. Mean respiratory carbon loss for all of the species was ca. 33%. Three groups of species were determined with respect to estimated seasonal carbon balance: high productivity (carbon gain of 24.0-21.5% of thallus carbon content) which included D. arctica, P. malacea, P. aphthosa, and Thamnolia vermicularis, lowest productivity (6.8%) for M. richardsonii, and intermediate for Cetraria cucullata (15.9%) and Stereocaulon alpinum (14.6%). Seasonal carbon gain is related to the maximal possible thallus growth. Estimates of annual lichen biomass increase in typical tundra communities ranged from 47.2 gDW m-2 for