Understanding nutrient biogeochemistry in agricultural catchments: the challenge of appropriate monitoring frequencies
Understanding nutrient biogeochemistry in agricultural catchments: the challenge of appropriate monitoring frequencies
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DOI：
10.1039/c4em00100a
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发表时间：
2014-01-01
影响因子：
5.5
通讯作者：
Keenan, P. O.
中科院分区：
文献类型：
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作者：
Bieroza, M. Z.;Heathwaite, A. L.;Keenan, P. O.
我们评估了不同频率的河流营养盐浓度测量来解释农业集水区的扩散污染。我们专注于三个营养成分，硝酸盐氮（NO3-N），总活性磷（TRP）和总磷（TP）观察使用传统的远程实验室为基础的，低频采样和自动化，原位高频监测。我们证明了低频常规营养监测的价值，在提供长期的数据变化，地表水和地下水营养浓度。相比之下，自动化的高频率的营养观测提供了深入了解营养动态的精细的时间结构，以响应全频谱的流动动力学。我们发现硝酸盐氮的同时原位测定和实验室测定之间具有良好的一致性（Pearson R = 0.93，p < 0.01）。对于磷组分：TP（R = 0.84，p < 0.01）和TRP（R = 0.79，p < 0.01）的相关性较差，这是由于现场观察到的P组分和抓斗样品的储存相关变化被低估。每小时原位自动监测和每周至每两周抓取采样获得的同步营养盐数据之间的详细比较揭示了低频采样在营养盐浓度的极端范围内的显着信息丢失。
We evaluate different frequencies of riverine nutrient concentration measurement to interpret diffuse pollution in agricultural catchments. We focus on three nutrient fractions, nitrate-nitrogen (NO3-N), total reactive phosphorus (TRP) and total phosphorus (TP) observed using conventional remote laboratory-based, low-frequency sampling and automated, in situ high-frequency monitoring. We demonstrate the value of low-frequency routine nutrient monitoring in providing long-term data on changes in surface water and groundwater nutrient concentrations. By contrast, automated high-frequency nutrient observations provide insight into the fine temporal structure of nutrient dynamics in response to a full spectrum of flow dynamics. We found good agreement between concurrent in situ and laboratory-based determinations for nitrate-nitrogen (Pearson's R = 0.93, p < 0.01). For phosphorus fractions: TP (R = 0.84, p < 0.01) and TRP (R = 0.79, p < 0.01) the relationships were poorer due to the underestimation of P fractions observed in situ and storage-related changes of grab samples. A detailed comparison between concurrent nutrient data obtained by the hourly in situ automated monitoring and weekly-to-fortnightly grab sampling reveals a significant information loss at the extreme range of nutrient concentration for low-frequency sampling.