Internal loading of phosphate in Lake Erie Central Basin
Internal loading of phosphate in Lake Erie Central Basin
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DOI：
10.1016/j.scitotenv.2016.11.133
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发表时间：
2017-02-01
影响因子：
9.8
通讯作者：
Kendall, Carol
中科院分区：
文献类型：
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作者：
Paytan, Adina;Roberts, Kathryn;Kendall, Carol
在20世纪80年代初，外部磷（P）负荷显著减少，随后水质改善后，伊利湖的水质在过去十年中大幅下降。有害藻类大量繁殖的频率和规模（主要在西部盆地）以及中央盆地缺氧底层沃茨的范围都有所增加。生态系统健康的下降，尽管满足外部磷负荷的目标，引发了新的努力，以了解磷循环的湖泊。我们使用孔隙水磷浓度剖面和沉积物岩心培养实验，以量化的磷通量从伊利湖中央盆地沉积物。此外，磷酸盐的氧同位素进行了调查，以评估相对于湖水中磷酸盐的同位素特征的沉积磷酸盐输入的同位素特征。外推的总P沉积物通量的孔隙水剖面的基础上，整个地区的中央盆地范围从300至1250公吨，每年使用的核心孵化实验的通量的基础上，每年约2400公吨的P通量计算。这些估计值占伊利湖磷总输入量的8-20%。沉积物中磷酸盐的同位素特征（约为18%）可以解释伊利湖中心盆地深水溶解态磷酸盐的非平衡同位素值，这与沉积物是伊利湖磷的重要内源相一致。(C)2016爱思唯尔B. V.保留所有权利。
After significant reductions in external phosphorus (P) loads, and subsequent water quality improvements in the early 1980s, the water quality of Lake Erie has declined considerably over the past decade. The frequency and magnitude of harmful algal blooms (primarily in the western basin) and the extent of hypoxic bottom waters in the central basin have increased. The decline in ecosystem health, despite meeting goals for external P loads, has sparked a renewed effort to understand P cycling in the lake. We use pore-water P concentration profiles and sediment cores incubation experiments to quantify the P flux from Lake Erie central basin sediments. In addition, the oxygen isotopes of phosphate were investigated to assess the isotopic signature of sedimentary phosphate inputs relative to the isotopic signature of phosphate in lake water. Extrapolating the total P sediment flux based on the pore-water profiles to the whole area of the central basin ranged from 300 to 1250 metric tons per year and using the flux based on core incubation experiments an annual flux of roughly 2400 metric tons of P is calculated. These estimates amount to 8-20% of the total external input of P to Lake Erie. The isotopic signature of phosphate in the extractable fraction of the sediments (similar to 18%) can explain the non-equilibrium isotope values of dissolved phosphate in the deep water of the central basin of Lake Erie, and this is consistent with sediments as an important internal source of P in the Lake. (C) 2016 Elsevier B.V. All rights reserved.