Nitrogen fixation by free-living cyanobacteria from different coastal sites in a high arctic tundra, Spitsbergen
Nitrogen fixation by free-living cyanobacteria from different coastal sites in a high arctic tundra, Spitsbergen
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DOI：
10.2307/1551994
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发表时间：
1997-11-01
期刊：
影响因子：
--
通讯作者：
Olsen, RA
中科院分区：
文献类型：
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作者：
Liengen, T;Olsen, RA
固氮率测定整个夏天的1994年在7个沿海站点的Broggerhalvoya，斯匹次卑尔根岛（78.5度N，11.6度E）北侧的样品，使用乙炔还原法在完整的土壤芯。所有这些地点都有一个含有蓝细菌的外壳，蓝细菌被认为是主要的固氮生物。地木耳是最丰富的蓝藻。将样品在19 ℃和200 μ E m（-2）s（-1）的恒定光强度下孵育。当样品在恒定条件下培养时，潜在的固氮活性范围为0.22至23.7 nmol乙烯产生cm（-2）h（-1）。固氮作用的空间差异大于季节差异。在从海中露出的地点，固氮活性与生态系统演替之间没有相关性，但自冰川退缩以来，固氮活性随时间而下降。有一个显着的相关性，在采样时的温度和固氮活性在恒定条件下测量。最低的固氮活性测定的网站，可提取的镁和钙的浓度最低，最低的C：N比。
Nitrogen fixation rates were measured throughout the summer of 1994 in samples from seven coastal sites at the north side of Broggerhalvoya, Spitsbergen (78.5 degrees N, 11.6 degrees E) using the acetylene reduction method on intact soil cores. All the sites had a crust containing cyanobacteria, which were considered to be the major nitrogen-fixing organisms. Nostoc commune was the most abundant cyanobacterium. The samples were incubated at 19 degrees C and a constant light intensity of 200 mu E m(-2) s(-1). The potential nitrogen fixation activities ranged from 0.22 to 23.7 nmol ethylene produced cm(-2) h(-1) when the samples were incubated under constant conditions. The spatial differences in nitrogen fixation were greater than the seasonal. No correlation between nitrogen fixation activities and ecosystem succession could be demonstrated at the sites emerged from the sea, but the nitrogen fixation activity decreased with time since the glacial retreat. There was a significant correlation between temperature at time of sampling and the nitrogen fixation activity measured under constant conditions. Lowest nitrogen fixation activities were measured at sites with the lowest concentrations of extractable magnesium and calcium and the lowest C:N ratios.