Water abstraction impacts stream ecosystem functioning via wetted-channel contraction
Water abstraction impacts stream ecosystem functioning via wetted-channel contraction
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DOI：
10.1111/fwb.12864
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发表时间：
2017-02-01
影响因子：
2.7
通讯作者：
Elosegi, Arturo
中科院分区：
文献类型：
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作者：
Arroita, Maite;Flores, Lorea;Elosegi, Arturo
为了满足对水、食品和能源不断增长的需求，全世界的取水量正在迅速增加。抽水可能会改变溪流和河流的水文状况，减少溪流内的栖息地，改变水质并影响河流群落。它还可能损害生态系统功能，尽管这方面很少得到评估。我们使用前后控制影响 (BACI) 设计，通过实验测试了取水对源头山区溪流功能的影响。我们量化了水的理化性质、生物膜生物量和活性（外切酶和新陈代谢）以及生态系统过程（养分循环、有机物保留和分解）的变化。取水不影响水体理化性质，但降低了单位表面积生物膜的生物量和碱性磷酸酶活性、养分的面积吸收和有机物的移动距离。它不影响沉水落叶层的生物膜代谢和分解，但减少了总分解。当按单位通道长度进行分析时，影响更大。由于湿通道的收缩，除底栖叶绿素-a 之外的所有变量均因提取而显着减少。本研究中观察到的生物膜生物量和活性以及养分吸收和总有机物分解的减少可能会增加下游河段的养分浓度，并减少向更高营养级的能量转移。永久性源头河流的生态系统服务可能会因湿河道宽度的减小而受到损害。
Water abstraction is rapidly increasing worldwide in order to respond to escalating demands for water, food and energy. Abstraction can alter the hydrological regime of streams and rivers, reduce in-stream habitats, change water quality and affect fluvial communities. It can also impair ecosystem functioning, although this aspect has been seldom assessed. We experimentally tested the effect of water abstraction on stream functioning in a headwater mountain stream using a before and after control-impact (BACI) design. We quantified changes in water physicochemical properties, biofilm biomass and activity (exo-enzymes and metabolism), and ecosystem processes (nutrient cycling, organic matter retention and breakdown). Water abstraction did not affect water physicochemical properties, but reduced the biomass and the alkaline phosphatase activity of biofilm per surface unit, the areal uptake of nutrients, and the travel distance of organic matter. It did not affect the biofilm metabolism and breakdown of submerged leaf litter, but decreased the total breakdown. The impacts were larger when analysed per unit of channel length. All variables, except benthic chlorophyll-a, were significantly reduced by abstraction, due to the contraction of the wetted channel. The decrease in the biomass and activity of biofilm, as well as in nutrient uptake and total organic matter breakdown observed in this study could increase nutrient concentration in downstream reaches and reduce the energy transfer to higher trophic levels. Ecosystem services of permanent headwater streams are likely to be compromised with the reduction of wetted-channel width.