Effects of dams and reservoirs on organic matter decomposition in the hyporheic zone in forest mountain streams
Effects of dams and reservoirs on organic matter decomposition in the hyporheic zone in forest mountain streams
复制标题
森林山溪流域水坝和水库对有机质分解的影响
DOI：
10.1007/s10750-022-04905-w
复制
发表时间：
2022
期刊：
影响因子：
2.6
通讯作者：
Tanaka Aki
中科院分区：
文献类型：
--
作者：
Kasahara Tamao;Li Yanda;Tanaka Aki
外来有机质的分解是源头河流的一个重要过程。河流筑坝改变了下游底栖区的分解速率，但对潜流分解的影响知之甚少。我们研究了水坝对潜流和底栖有机物分解的影响，在五个季节，在日本西部的两个森林山溪中使用棉带试验。腐解速率在春、雨、秋三季坝下游低于非整治河段，冬、夏季差异不大。在一条河流中，潜流分解率与底栖速率相当，而在另一条河流中则较低。分解率没有不同的粗和细网眼袋在许多季节在所有网站，和大型无脊椎动物的密度都很低，这表明大型无脊椎动物的分解在潜流区的贡献是小的。这些结果表明，潜流区是一个重要的分解区，水坝的存在改变了潜流分解在某些季节。因此，在研究水坝和水库对河流生态系统过程的影响时，必须同时研究底栖区和潜流区。
Decomposition of allochthonous organic matter is an essential process in headwater streams. Damming of streams alters decomposition rates in the benthic zone downstream, but little is known about the effects on hyporheic decomposition. We examined the effects of dams on hyporheic and benthic organic matter decomposition, using the cotton-strip assay over five seasons, in two forest mountain streams in western Japan. The decomposition rates in the hyporheic zone were lower downstream of the dams than at the unregulated reach in spring, rainy season and fall, but they did not differ in winter and summer. Hyporheic decomposition rates were comparable to the benthic rates in one river and were lower in the other river. Decomposition rates did not differ between coarse- and fine-mesh bags in many seasons at all sites, and the densities of macroinvertebrates were low, suggesting that the contribution of macroinvertebrate to decomposition in the hyporheic zone was small. These results showed that the hyporheic zone is an important zone for decomposition and that presence of dams altered the hyporheic decomposition in some seasons. Thus, it is crucial to examine both the benthic and hyporheic zones when addressing the effects of dams and reservoirs on stream ecosystem processes.