Phosphorus release from sediments in a river-valley reservoir in the northern Great Plains of North America

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• 作者：L. E. Doig ; R. L. North ; J. J. Hudson ; C. Hewlett ; K.-E. Lindenschmidt…
• 关键词：Lake Diefenbaker ; Anoxic ; Internal phosphorus loading ; Phosphorus fractionation ; Iron ; Dissolved oxygen ; Prairie
• 刊名：Hydrobiologia
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：787
• 期：1
• 页码：323-339
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Freshwater & Marine Ecology; Ecology; Zoology;
• 出版者：Springer International Publishing
• ISSN：1573-5117
• 卷排序：787

文摘

Aside from a companion investigation to this study, there are currently no peer-reviewed phosphorus (P) release rate data for northern North American (i.e., Canadian) reservoirs. Using Lake Diefenbaker, Saskatchewan, Canada as a case study, we tested the effect of variation in overlying water DO conditions on the P release rates from sediment cores. Sediment cores from four down-reservoir locations in Lake Diefenbaker were incubated under high (>8 mg l−1), low (2–3 mg l−1), or anoxic (<1 mg l−1) DO concentrations. Sediment cores were then analyzed for total P (TP) and three geochemical P fractions to assess how the DO regime influenced sediment P inventory. Maximum P release rates were highest under anoxic conditions and similar among sites (15.0–20.3 mg m−2 day−1), with the low-DO rates intermediate to the high-DO and anoxic P fluxes. Predictive internal P loading models considering only hypolimnetic anoxia may therefore oversimplify and thus underestimate P mobilization in situ. Non-apatite inorganic P (54 ± 10% across sites) from the top 1 cm of the sediment profile was the main source of P released during incubations, indicating that sampling on a coarser scale of resolution could obscure the relationship between sediment geochemistry and short-term P flux.