Tracing carbon sources in small urbanising streams: catchment-scale stormwater drainage overwhelms the effects of reach-scale riparian vegetation
Tracing carbon sources in small urbanising streams: catchment-scale stormwater drainage overwhelms the effects of reach-scale riparian vegetation
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追踪小型城市化溪流中的碳源：流域规模的雨水排放压倒了河段规模的河岸植被的影响
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Thompson
中科院分区：
文献类型：
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作者：
Samantha J. Imberger;P. Cook;M. Grace;R. Thompson
摘要 1. 有机物为水生系统提供能量和营养。其来源和加工过程的改变会对水质和食物网的稳定性和结构产生影响。尽管全世界都认识到城市化的影响，但对流域规模的城市雨水排放连接和河段河岸植被对有机质来源的相对重要性的认识有限。 2. 我们研究了流域规模的城市雨水排放连接和河段规模的河岸植被覆盖对小溪有机质来源的影响。利用稳定同位素和元素比率（即 d 13 C、d 15 N 和 C:N），我们追踪了微生物呼吸碳的来源以及溶解有机碳 (DOC)、悬浮颗粒有机物 (POM) 和底栖粗颗粒有机物 (CPOM) 的常量。 3.流域规模的城市雨水排水连接显着增加了不稳定有机物对POM和DOC积存量的贡献。尽管不稳定的 DOC 的来源尚不清楚，但 POM 的不稳定性更大是城市化程度较高的河流中本地有机物质输入增加的结果。 4. 虽然河段规模的河岸植被是大多数地点观察到的以陆地为主的 CPOM 的最有可能来源，但覆盖范围的增加对 POM 或 DOC 现有种群的来源没有显着影响。我们得出的结论是，流域规模的雨水排放影响压倒了河段规模的河岸植被对小溪中 POM 和 DOC 的来源和稳定性的影响。 5. 我们的研究结果表明，在不对流域规模的雨水排放连接进行改造的情况下，河岸植被的保护或恢复不足以减轻城市化对这些小溪流中有机物来源、不稳定性和加工的影响。
SUMMARY 1. Organic matter provides energy and nutrients to aquatic systems. Alterations to its sources and processing have repercussions for water quality and food-web stability and structure. Despite worldwide recognition of the impacts of urbanisation, there is limited understanding of the relative importance of catchment-scale urban stormwater drainage connection and reach-scale riparian vegetation on organic matter sources. 2. We investigated the effects of catchment-scale urban stormwater drainage connection and reachscale riparian vegetation cover on organic matter sources in small streams. Using stable isotopes and elemental ratios (i.e. d 13 C, d 15 N and C : N), we traced the origin of microbially respired carbon and standing stocks of dissolved organic carbon (DOC), suspended particulate organic matter (POM) and benthic coarse particulate organic matter (CPOM). 3. Catchment-scale urban stormwater drainage connection significantly increased the contribution of labile organic matter to POM and DOC standing stocks. Greater POM lability was a product of increased inputs of autochthonous organic matter in more heavily urbanised streams, although the origin of labile DOC was less clear. 4. While reach-scale riparian vegetation was the most likely source of the terrestrially dominated CPOM observed across most sites, increasing cover had no significant effect on the origin of POM or DOC standing stocks. We conclude that catchment-scale stormwater drainage impacts overwhelm the effects of reach-scale riparian vegetation on the sources and lability of POM and DOC in small streams. 5. Our results suggest that the protection or restoration of riparian vegetation, in the absence of modifications to catchment-scale stormwater drainage connection, is insufficient to mitigate the effects of urbanisation on organic matter sources, lability and processing in these small streams.