Ammonium uptake and mineralization in prairie streams: chamber incubation and short‐term nutrient addition experiments
Ammonium uptake and mineralization in prairie streams: chamber incubation and short‐term nutrient addition experiments
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草原溪流中的铵吸收和矿化：室培养和短期养分添加实验
DOI：
10.1111/j.1365-2427.2007.01870.x
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发表时间：
2007
影响因子：
2.7
通讯作者：
W. Dodds
中科院分区：
文献类型：
--
作者：
J. O’Brien;W. Dodds
总结1。我们使用了两种不同的方法来估计国王溪（一条草原溪流）南北分支的环境铵循环。通过室内实验确定了从溪流中收集的附着生物膜和丝状藻类对铵的吸收和矿化率。基于铵浓度与吸收速率之间的关系，我们还进行了一系列短期全流程铵添加实验，以估计在环境流浓度下的吸收速率。2. 室内实验扩大到整个河流的水平，得出北支的环境总吸收量估计为0.08 lg (2 s)1，南支为0.16 lg (2 s)1。在两条河流中，特定基质的矿化估计高于吸收量。3. 基质特异性测量结果表明，水洼生境的铵吸收量高于水洼生境。短期铵加成实验的结果支持了这些发现。4. 短期铵添加实验表明，随着铵浓度的增加，吸收速率趋于饱和。观察到的摄取速率饱和符合Michaelis-Menten关系。5. 从室内实验得出的吸收估算值与基于全流实验的环境铵吸收估算值相似，并且与先前在Kings Creek使用稳定同位素示踪方法得出的铵吸收和矿化估算值相当。
SUMMARY 1. We used two separate approaches to estimate ambient ammonium cycling in the north and south branches of Kings Creek, a prairie stream. Chamber experiments were conducted to determine ammonium uptake and mineralization rates associated with epilithic biofilms and filamentous algae collected from the streams. A series of short-term whole-stream ammonium addition experiments were also conducted to estimate the rate of uptake at ambient stream concentrations, based on the relationship between ammonium concentrations and uptake rates. 2. Chamber experiments were scaled up to whole-stream levels, resulting in ambient gross uptake estimates of 0.08 lg )2 s )1 for the north branch and 0.16 lg )2 s )1 for the south branch. The substrata-specific estimates of mineralization were higher than uptake in both streams. 3. Substrata-specific measurements indicated that ammonium uptake is higher in riffle habitats than in pools habitats. The results of the short-term ammonium addition experiments support these findings. 4. Short-term ammonium addition experiments show that uptake rates saturate with increasing ammonium concentrations. The observed saturation of uptake rates is consistent with a Michaelis–Menten relationship. 5. Scaled estimates of uptake from the chamber experiments were similar to estimates of ambient ammonium uptake based on the whole-stream experiments, and were comparable with previous estimates of ammonium uptake and mineralization made by using stable isotope tracer methods in Kings Creek.