Mechanical abrasion and organic matter processing in an Iowa stream
Mechanical abrasion and organic matter processing in an Iowa stream
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爱荷华州河流中的机械磨损和有机物处理
DOI：
10.1023/a:1003713307849
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发表时间：
1999
期刊：
影响因子：
2.6
通讯作者：
Tamara C. Griesel
中科院分区：
文献类型：
--
作者：
S. Heard;G. Schultz;C. Ogden;Tamara C. Griesel
有机物处理速率是研究河流生态系统功能和河流群落生态学的重要参数。大多数关于溪流中有机物处理的研究都使用叶包或垃圾袋中的叶子，这些叶子是固定的，并在运输过程中和溪流底部与石头部分接触。因此，这些研究可能低估了机械磨损对整体处理率（粗有机碎屑到细颗粒）的贡献。我们比较了叶处理率在垃圾袋与无石头（5厘米粉碎石灰石压载）在大米尔克里克，东部爱荷华州。在三个实验中的两个中，处理在有石头的袋子中比在没有石头的袋子中显著更先进：在有石头的袋子中，叶质量减少到小碎片（1.4-9.5 mm）的分数分别高出45%和93%。在第四个实验中，我们比较了石头和碎纸机（Gammarus pseudolimnaeus，在接近自然的密度）对破碎的落叶袋的影响。这个实验表明，机械和生物制剂的处理是大致同等重要的大米尔克里克。我们的研究结果表明，机械磨损可以是一个重要的贡献者，在流中的有机物处理。如果是这样的话，它可能是收集器使用的更细颗粒的重要来源。垃圾袋和叶包实验可能会低估总处理率和高估微生物和无脊椎动物处理的相对重要性。
Rates of organic matter processing are key parameters for studies of stream ecosystem function and stream community ecology. Most studies of organic matter processing in streams use leaves in leafpacks or litterbags, which are immobilized and partly shielded from contact with stones in transport and in the stream bottom. As a result, these studies may underestimate the contribution of mechanical abrasion to overall processing rate (of coarse organic detritus to fine particles). We compared leaf processing rates in litter bags with and without stones (5 cm crushed limestone ballast) in Big Mill Creek, eastern Iowa. In two of three experiments, processing was significantly more advanced in bags with stones than in bags without stones: the fraction of leaf mass reduced to small fragments (1.4–9.5 mm) was 45% and 93% higher in bags with stones. In a fourth experiment, we compared the effects of stones and shredders (Gammarus pseudolimnaeus, at near-natural densities) on fragmentation of leaves in litterbags. This experiment indicated that mechanical and biological agents of processing are roughly equally important in Big Mill Creek. Our results indicate that mechanical abrasion can be an important contributor to organic matter processing in streams. If so, it may be an important source of the finer particles used by collectors. Litterbag and leafpack experiments may underestimate total processing rates and overestimate the relative importance of processing by microbes and invertebrates.