Faculty of Science and Engineering, Waseda University, 2-2, Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan.
New Phytol. 2010 Apr;186(2):451-60. doi: 10.1111/j.1469-8137.2010.03180.x. Epub 2010 Feb 2.
*We examined the photosynthetic characteristics and net primary production of biological soil crusts to evaluate their contribution to the carbon cycle in the High Arctic glacier foreland. *Biological soil crust samples were collected from a deglaciated area in Ny-Alesund, Svalbard, Norway. Net photosynthetic rates (Pn) and dark respiration rates (R) of biological soil crusts were determined using CO(2) gas exchange rates. We examined the effects of moisture conditions, temperature and photon flux density on Pn and R, and estimated the net primary production by a model based on the relationships between abiotic factors and Pn and R. *The maximum Pn value occurred at 50% of the maximum water-holding capacity. Pn decreased with increasing temperature and dropped below zero at high temperatures (c. > 13 degrees C). The estimated net primary production of the biological soil crust was greater than the net primary production of other vegetation when based on ground surface area, during the early stage of primary succession. Model simulation showed that the net primary production of the biological soil crust decreased with increasing temperature. *These results suggest that biological soil crust productivity plays an important role in the carbon cycle during the early stage of succession of the High Arctic glacier foreland, and is susceptible to temperature increases from global warming.
我们研究了生物土壤结皮的光合作用特性和净初级生产力，以评估它们对高北极冰川前缘碳循环的贡献。生物土壤结皮样本是从挪威斯瓦尔巴群岛的 Ny-Alesund 去冰川区采集的。使用 CO(2)气体交换率来测定生物土壤结皮的净光合速率（Pn）和暗呼吸速率（R）。我们研究了水分条件、温度和光子通量密度对 Pn 和 R 的影响，并根据生物因子与 Pn 和 R 之间的关系，用模型估算了净初级生产力。最大 Pn 值出现在最大持水能力的 50%时。随着温度的升高，Pn 下降，在高温下（约> 13 摄氏度）降至零以下。基于地面面积，在初级演替的早期阶段，生物土壤结皮的净初级生产力大于其他植被的净初级生产力。模型模拟表明，生物土壤结皮的净初级生产力随着温度的升高而降低。这些结果表明，生物土壤结皮生产力在高北极冰川前缘演替的早期阶段对碳循环起着重要作用，并且容易受到全球变暖引起的温度升高的影响。
