Worldwide retention of nutrient silicon by river damming: From sparse data set to global estimate
Worldwide retention of nutrient silicon by river damming: From sparse data set to global estimate
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DOI：
10.1002/2014gb004875
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发表时间：
2014-08-01
影响因子：
5.2
通讯作者：
Van Cappellen, Philippe
中科院分区：
文献类型：
--
作者：
Maavara, Taylor;Duerr, Hans H.;Van Cappellen, Philippe
河流筑坝是对水文循环的一种主要人为干扰，有可能深刻改变河流、湖泊和沿海地区营养硅（Si）的可利用性。然而，对大坝对河流硅通量影响的全球评估受到水库硅收支数据集稀少的限制。为了缓解这一限制，我们利用现有关于大坝对溶解硅（DSi）滞留的数据来校准一个水库系统中溶解硅和活性颗粒硅（PSi）生物地球化学循环的机制模型。模型校准得出了水库内硅质初级生产力与外部溶解硅供应之间的关系。利用这种关系以及对流域硅负荷的估算，该模型可以计算出任何给定水库中活性硅（RSi = DSi + PSi）的总滞留量。蒙特卡罗分析考虑了水库特性变化的影响，并生成了一种全球关系，该关系将水库中活性硅的平均滞留量预测为水停留时间的函数。将这种关系应用于全球水库和大坝数据库，以估算全球筑坝对硅的滞留量。结果显示，大坝滞留了163吉摩尔/年（9.8太克二氧化硅/年）的溶解硅和372吉摩尔/年（22.3太克二氧化硅/年）的活性硅，占全球河流活性硅负荷的5.3%。
Damming of rivers represents a major anthropogenic perturbation of the hydrological cycle, with the potential to profoundly modify the availability of nutrient silicon (Si) in streams, lakes, and coastal areas. A global assessment of the impact of dams on river Si fluxes, however, is limited by the sparse data set on Si budgets for reservoirs. To alleviate this limitation, we use existing data on dissolved Si (DSi) retention by dams to calibrate a mechanistic model for the biogeochemical cycling of DSi and reactive particulate Si (PSi) in reservoir systems. The model calibration yields a relationship between the annual in-reservoir siliceous primary productivity and the external DSi supply. With this relationship and an estimate of catchment Si loading, the model calculates the total reactive Si (RSi=DSi+PSi) retention for any given reservoir. A Monte Carlo analysis accounts for the effects of variations in reservoir characteristics and generates a global relationship that predicts the average reactive Si retention in reservoirs as a function of the water residence time. This relationship is applied to the Global Reservoirs and Dams database to estimate Si retention by damming worldwide. According to the results, dams retain 163 Gmol yr(-1) (9.8 Tg SiO2 yr(-1)) of DSi and 372 Gmol yr(-1) (22.3 Tg SiO2 yr(-1)) of RSi, or 5.3% of the global RSi loading to rivers.