Oxygen and dissolved organic carbon control release of N, P and Fe from the sediments of a shallow, polymictic lake
Oxygen and dissolved organic carbon control release of N, P and Fe from the sediments of a shallow, polymictic lake
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DOI：
10.1007/s11368-015-1298-9
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发表时间：
2016-03
影响因子：
3.6
通讯作者：
S. Müller;S. Mitrovic;D. Baldwin
中科院分区：
文献类型：
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作者：
S. Müller;S. Mitrovic;D. Baldwin
目的我们研究了一个浅水多组分水库沉积物中营养盐释放的潜在原因，与许多其他浅水湖泊不同，该水库没有接受大量的营养盐负荷。据推测，沉积物中释放的营养盐的量更大的缺氧，而不是好氧的条件下，氮（N）和磷（P）的释放是有限的不同类型的有机substrate.Materials和methodsSediment培养实验在夏季和冬季的好氧和缺氧条件下进行。进行了添加不同类型的溶解性有机基质（葡萄糖、乙酸盐、甲酸盐和丙酸盐）的缺氧培养实验。在28天内监测培养室上清液中亚硝酸盐和硝酸盐（NOx−-N）、铵（NH 4 +-N）、可溶性活性P（srP）和铁（Fe（II））的浓度。热分层监测原位17个月和沉积物组成进行了analysed.Results和discussionNOx−-N浓度增加了5.67 ± 0.33毫克N l− 1在缺氧条件下，但在好氧处理低得多。在缺氧和好氧处理中srP的释放量较低（0.004 ± 0.001 mg P l−1），但在添加甲酸盐的情况下，srP的释放量为0.027 ± 0.015 mg P l− 1。Fe（II）的释放主要受葡萄糖的刺激（25.59 ± 4.28 mg Fe l−1）。磷释放远远低于观察到的富营养化湖泊。磷释放似乎不是由于减少铁矿物和并发溶解的正磷酸盐，经常被报道为最普遍的途径，从厌氧湖泊sediments. ConclusionsFe和P释放湖泊沉积物的通量可以相互独立，可以控制溶解有机C。此外，该研究证实了氧的有效性在控制沉积物中营养盐释放的作用。
PurposeWe examined potential causes of nutrient release from the sediments of a shallow polymictic reservoir that, unlike many other shallow lakes, had not received large amounts of nutrient loading. It was hypothesised that the sediments released greater amounts of nutrients under anoxic rather than oxic conditions and that nitrogen (N) and phosphorus (P) release was limited by the availability of different types of organic substrate.Materials and methodsSediment incubation experiments under oxic and anoxic conditions were conducted in summer and in winter. One anoxic incubation experiment with the addition of different types of dissolved organic substrate (glucose, acetate, formate and propionate) was carried out. Concentrations of nitrite and nitrate (NOx−-N), ammonium (NH4+-N), soluble reactive P (srP) and iron (Fe(II)) were monitored in the supernatant of the incubation chambers over 28 days. Thermal stratification was monitored in situ for 17 months and sediment composition was analysed.Results and discussionNOx−-N concentration increased by 5.67 ± 0.33 mg N l−1in anoxic conditions but was much lower in oxic treatments. Release of srP was low in anoxic and oxic treatments (0.004 ± 0.001 mg P l−1) but was stimulated by 0.027 ± 0.015 mg P l−1under additions of formate. Fe(II) release was mostly stimulated by glucose additions (25.59 ± 4.28 mg Fe l−1). P release was much lower than observed in eutrophic lakes. P release does not appear to be as a result of the reduction of Fe minerals and concurrent dissolution of orthophosphate, often reported as the most prevalent pathway for P release from anaerobic lake sediments.ConclusionsIron and P flux from lake sediments can be independent from each other and can be controlled by dissolved organic C. Further, the study confirms the role of oxygen availability in controlling nutrient release from the sediments.