Sediment Phosphorus Release at Beaver Reservoir, Northwest Arkansas, USA, 2002–2003: A Preliminary Investigation
Sediment Phosphorus Release at Beaver Reservoir, Northwest Arkansas, USA, 2002–2003: A Preliminary Investigation
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美国阿肯色州西北部海狸水库沉积物磷释放量，2002-2003 年：初步调查
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发表时间：
2007
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通讯作者：
M. Matlock
中科院分区：
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作者：
Sumit Sen;B. Haggard;I. Chaubey;K. Brye;T. A. Costello;M. Matlock
从底层沉积物中释放的磷(P)可能是上覆水柱的一个重要来源，有可能维持和促进湖泊和水库中藻类的生长和富营养化条件。因此，本研究的目的是：(1)从阿肯色州西北部的海狸水库采集完整的沉积物岩心，测量好氧和厌氧条件下的磷通量；(2)评估水库沿线在好氧和厌氧条件下测得的沉积物磷通量的空间变异性；(3)比较海狸水库的外部和内部磷负荷。2003年6月、2003年9月和2004年2月，在代表湖泊、过渡带和河流带的3个地点采集了6个完整的沉积物岩芯，并在∼22°C的黑暗中培养了21天。在前5天和之后的每隔一天，每天从每个岩芯的上覆水柱中采集水样，并分析可溶性活性磷(SRP)。在厌氧条件下，沉积物磷通量(<；0.01~1.77mgm−2天−1)一般大于好氧条件下测得的(<；0.01~0.89 mg m−2天−1)。底泥磷通量存在一定的空间变异性，河流和过渡带的土壤磷通量普遍最大。在2003年9月从过渡带采集的岩芯中，在厌氧条件下观测到了最大的沉积物磷通量。好氧(0.09mgm−2d−1)和厌氧(0.31mgm−2d−1)条件下的平均底泥磷通量大于从海狸水库支流估算的外部磷通量(0.05mgm−2d−1)。结果表明，河狸水库底泥的年内磷负荷(7 mg年−1)不到年外磷负荷(∼81 mg P年−1)的10%。内部磷负荷很大，但考虑到海狸水库的大表面积，目前管理这种磷来源并不划算。
Phosphorus (P) release from bottom sediments can be a significant source to the overlying water column, potentially maintaining and enhancing algal growth and eutrophic conditions in lakes and reservoirs. Thus, the objectives of this study were to: (1) measure P flux under aerobic and anaerobic conditions from intact sediment cores collected at Beaver Reservoir, northwest Arkansas, (2) evaluate the spatial variability in measured sediment P flux under aerobic and anaerobic conditions along the reservoir, and (3) compare external and internal P loads to Beaver Reservoir. Six intact sediment cores were collected at three sites representing the lacustrine, transitional, and riverine zones during June 2003, September 2003 and February 2004 and incubated for 21 days in the dark at ∼22°C. Three cores from each site were incubated under aerobic conditions and anaerobic conditions. Water samples were collected from the overlying water column in each core daily for the first five days and every other day thereafter and analyzed for soluble reactive phosphorus (SRP). Water removed from the core was replaced with filtered lake water, maintaining a constant overlying water volume of 1 l. Sediment P flux under anaerobic conditions (<0.01–1.77 mg m−2 day−1) was generally greater than that measured under aerobic conditions (<0.01–0.89 mg m−2 day−1). Some spatial variability existed in sediment P flux where P flux was generally greatest at the sites in the riverine and transitional zones. Maximum sediment P flux was observed under anaerobic conditions in cores collected from the transitional zone during September 2003. Average sediment P flux under aerobic conditions (0.09 mg m−2 day−1) and anaerobic conditions (0.31 mg m−2 day−1) was greater than the external P flux (0.05 mg m−2 day−1) estimated from the Beaver Reservoir tributaries. Results showed that the annual internal P load (7 Mg year−1) from bottom sediments in Beaver Reservoir was less than 10% of the annual external P load (∼81 Mg P year−1). The internal P load was significant, but it would not currently be cost effective to manage this P source given the large surface area of Beaver Reservoir.