Nitrogen Fixation in Arctic Coastal Tundra in Relation to Vegetation and Micro-Relief
ABSTRACT. A study to estimate nitrogen fixation input. in arctie c m t d tundra was carried out using the acetylene reduction assay. Areal estimation was attempted by high intensity sampling over a limited area of tundra containing both high-centred and low-centred polygons with their corresponding...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.547.3554 http://pubs.aina.ucalgary.ca/arctic/Arctic26-2-130.pdf |
| Summary: | ABSTRACT. A study to estimate nitrogen fixation input. in arctie c m t d tundra was carried out using the acetylene reduction assay. Areal estimation was attempted by high intensity sampling over a limited area of tundra containing both high-centred and low-centred polygons with their corresponding variations in micro-vegetation. The highest average rates of acetylene reduction were obtained from cores in damp interpolygonal troughs (10.50 pmoles ethylene/m.z-hr) where mats of the blue-green alga Nostoc were abundant. Wet moss-algal associations in hydric meadows showed high nitrogenase activity (average 6.86 pmoles ethylene/m.z-hr) and dry high-centred polygons were comparatively inactive (average 2.80 moles ethylene/m.z-hr). The lichens Peltigera sp. and Stereocaulon sp. were the most active nitrogen fixers in the drier tundra. Nitrogen fixation increased with rising temperature with a measured Ql0 for Nostoc commune of 3.7. RÉSUMÉ: Fixation de l'azote dans la toundra côti2re arctique, par rapport à la végétation et au micro-relief. Les auteurs ont mené une étude pour estimer l'apport d'azote fixé dans la toundra côtière arctique, par le titrage de la réduction par |
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