Nitrate uptake across biomes and the influence of elemental stoichiometry: A new look at LINX II
Nitrate uptake across biomes and the influence of elemental stoichiometry: A new look at LINX II
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DOI：
10.1002/2016gb005468
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发表时间：
2016-08
影响因子：
5.2
通讯作者：
A. Wymore;A. A. Coble-A.;B. Rodríguez‐Cardona;W. McDowell
中科院分区：
文献类型：
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作者：
A. Wymore;A. A. Coble-A.;B. Rodríguez‐Cardona;W. McDowell
考虑到最近增加的人为氮负荷，这是至关重要的，以确定控制N的去除和保留在水生生态系统中，因为N的命运有后果的河流和下游生态系统的水质。硝酸盐（NO3−）的生物吸收是氮从这些生态系统中去除的主要途径。在这里，我们使用来自第二次Lotic Intersite NitrogeneExperiment（LINX II）的数据进行多变量分析，以确定生物群落中NO3−吸收速度变化的主要驱动因素。在北美的69个研究流域中，溶解有机碳：NO3−比率和光合有效辐射被确定为解释NO3−吸收速度的两个最重要的预测变量。然而，在特定的生物群落中，NO3-吸收速度的预测变量各不相同，包括各种物理，化学和生物属性。我们的分析证明了元素化学计量对NO3−吸收速度的广泛控制以及生物群落特异性预测因子的重要性。了解这种空间变化对特定生物群落的流域管理和NO3-的下游输出，以及描述溪流和河流中N动态的空间显式全球模型的开发具有重要意义。
Considering recent increases in anthropogenic N loading, it is essential to identify the controls on N removal and retention in aquatic ecosystems because the fate of N has consequences for water quality in streams and downstream ecosystems. Biological uptake of nitrate (NO3−) is a major pathway by which N is removed from these ecosystems. Here we used data from the second Lotic Intersite Nitrogen eXperiment (LINX II) in a multivariate analysis to identify the primary drivers of variation in NO3− uptake velocity among biomes. Across 69 study watersheds in North America, dissolved organic carbon:NO3− ratios and photosynthetically active radiation were identified as the two most important predictor variables in explaining NO3− uptake velocity. However, within a specific biome the predictor variables of NO3− uptake velocity varied and included various physical, chemical, and biological attributes. Our analysis demonstrates the broad control of elemental stoichiometry on NO3− uptake velocity as well as the importance of biome‐specific predictors. Understanding this spatial variation has important implications for biome‐specific watershed management and the downstream export of NO3−, as well as for development of spatially explicit global models that describe N dynamics in streams and rivers.