Nitrogen Cycling in Natural Waters using In Situ, Reagentless UV Spectrophotometry with Simultaneous Determination of Nitrate and Nitrite
详细信息 查看全文
- 作者：Richard C. Sandford ; Alexandra Exenberger ; Paul J. Worsfold
- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：December 15, 2007
- 年：2007
- 卷：41
- 期：24
- 页码：8420 - 8425
- 全文大小：1063K
- 年卷期：v.41,no.24(December 15, 2007)
- ISSN：1520-5851
文摘
Reliable, high temporal, and spatial resolution data is essential for enhancing our understanding of aquatic nitrogen biogeochemical cycling. This paper describes a novel UV spectrophotometric sensor (ProPS, TriOS GmbH, Oldenburg, Germany) for the real time, in situ, high resolution simultaneous mapping of nitrate/nitrite (linearity 0.01 – 6 mg N L−1, RSD’s NO3-N 4–10%, NO2-N 7–14%) in fresh and estuarine waters. Good agreement (t test at p = 0.05) was found with MOOS-1 certified reference material and with reference segmented flow analysis data. River Taw deployments identified a diurnal cycle for NO3-N (0.22–0.63 mg L−1, RSD 3.9%) and for NO2-N (0.01–0.28 mg L−1, RSD 12.4%) with the photo-oxidation of dissolved organic nitrogen a source of diurnal nitrate/nitrite, and a large cyclical amplitude (30–62% of mean nitrate/nitrite). In situ Tamar Estuary nitrate/nitrite concentrations, mapped through the salinity gradient, were strongly correlated with suspended particulate material and inversely correlated with dissolved oxygen and pH, indicating midestuarine, bacterially mediated nitrification/denitrification, with the raised estuarine nitrite also significantly correlated with particulate organic nitrogen. Such previously unquantified inputs have important implications for N loadings calculated from coarse scale sampling and laboratory analysis, pollution assessment, and our understanding of the biological rhythms of aquatic organisms.