Soil and root respiration in mature Alaskan black spruce forests that vary in soil organic matter decomposition rates
Soil and root respiration in mature Alaskan black spruce forests that vary in soil organic matter decomposition rates
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DOI：
10.1139/x04-159
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发表时间：
2005
影响因子：
2.2
通讯作者：
J. Vogel;D. Valentine;R. Ruess
中科院分区：
文献类型：
--
作者：
J. Vogel;D. Valentine;R. Ruess
Climate warming at high latitudes is expected to increase root and microbial respiration and thus cause an increase in soil respiration. We measured the root and microbial components of soil respiration near Fairbanks, Alaska, in 2000 and 2001, in three black spruce (Picea mariana (Mill) B.S.P.) forests. We hypothesized faster decomposition correlates with greater amounts of both root and microbial contributions to soil respiration. Contrary to our prediction, the site with the coolest summer soil temperatures and slowest decomposition (site identification "high-np") had signifi- cantly (p < 0.05) greater growing season soil respiration (485 g C·m -2 ·year -1 ) than the two other sites (372 and 332 g C·m -2 ·year -1 ). Spruce C allocation to root respiration was significantly greater, and fine-root N concentration was 10% and 12% greater (p < 0.05) at high-np than at the other two sites. High-np spruce foliage was also more enriched in 13 C and depleted in 15 N, suggesting either lower available moisture or slower N turnover. Either factor could drive greater C allocation to roots; however, a literature review suggests moisture deficit corresponds to greater C allocation to roots in black spruce forests across the boreal ecosystem. Controls on spruce C allocation need to be resolved before making the generalization that soil respiration will increase with warming in this forest type. Resume : Le rechauffement du climat aux latitudes elevees devrait augmenter la contribution tant des racines que des decomposeurs heterotrophes a la respiration du sol. Les auteurs mesure les composantes racinaires et heterotrophes de la respiration du sol pres de Fairbanks en Alaska, en 2000 et 2001, dans trois forets d'epinette noire (Picea mariana (Mill.) B.S.P.) situees a differents endroits dans le paysage. Ils ont assume qu'une decomposition plus rapide corres- pondrait a une plus grande contribution racinaire et heterotrophe a la respiration du sol. Contrairement a leurs predic- tions cependant, la respiration du sol pendant la saison de croissance etait significativement plus elevee (p < 0,05) dans le site avec les temperatures estivales du sol les plus froides et la decomposition la plus lente (site ID « np-eleve »)
