Leaf and wood breakdown in cave streams
Leaf and wood breakdown in cave streams
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洞穴溪流中的树叶和木材分解
DOI：
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发表时间：
2001
影响因子：
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通讯作者：
E. F. Benfield
中科院分区：
文献类型：
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作者：
K. Simon;E. F. Benfield
位于地表附近的洞穴溪流是连接陆地环境能源和深层地下水的重要交错带。我们在5个洞穴溪流和2个没有洞穴溪流的洞穴溪流中研究了树叶和木材的分解和运输，这些洞穴溪流有大的开口，允许从地表输入垃圾。白栎(Quercus Alba)在洞穴溪流中的树叶崩解率超过了地表溪流中白橡树树叶的报告数值范围。有碎叶的无脊椎动物的溪流中，叶的破碎速度更快，并且叶的破碎率与叶包中的碎叶密度呈正相关。木材破碎率很快，部分原因是我们使用了木材单板，而且不同的溪流没有区别。树叶和木材的微生物定植遵循典型的地表径流模式：真菌生物量和微生物呼吸作用在62d内达到峰值，然后在树叶上下降，但木材上的生物量和呼吸作用逐渐增加并达到平台期。与地表溪流不同，没有凋落物并不会加速洞穴溪流中粗颗粒有机物(CPOM)的分解和微生物的定植，这显然是因为洞穴溪流中的营养物质不受限制。所有溪流的营养水平都很高，因此营养物质的增加对洞穴溪流中木材的微生物生物量和呼吸作用几乎没有影响。树叶和树枝的运输距离较短，与破碎率相结合，表明CPOM有效地保留在其入口点附近。
Cave streams lying near the surface are important ecotones connecting energy sources from the terrestrial environment to deep groundwater. We examined leaf and wood breakdown and transport in 5 cave streams with, and 2 without, large openings that allow litter input from the surface. White oak (Quercus alba) leaf breakdown rates in cave streams spanned the range of values reported for white oak leaves in surface streams. Leaf breakdown was faster in streams with leaf-shredding invertebrates, and leaf breakdown rates were positively correlated with shredder density in leaf packs. Wood breakdown rates were fast, partly a result of the wood veneer we used, and did not differ among streams. Microbial colonization of leaves and wood followed a pattern typical of surface streams: fungal biomass and microbial respiration peaked within 62 d and then declined on leaves, but biomass and respiration on wood gradually increased to a plateau. Coarse particulate organic matter (CPOM) breakdown and microbial colonization in cave streams were not accelerated by the absence of litter, unlike surface streams, apparently because nutrients were not limiting in cave streams. Nutrient levels were high in all streams, so nutrient enrichment had little effect on microbial biomass and respiration on wood in cave streams. Leaf and stick transport distances were short and, when combined with breakdown rates, suggest that CPOM is efficiently retained near its entry point.