Internal phosphorus loading from sediments causes seasonal nitrogen limitation for harmful algal blooms
Internal phosphorus loading from sediments causes seasonal nitrogen limitation for harmful algal blooms
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沉积物内部的磷负荷导致有害藻华的季节性氮限制
DOI：
10.1016/j.scitotenv.2017.12.348
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发表时间：
2018-06-01
影响因子：
9.8
通讯作者：
Zhang, Chaosheng
中科院分区：
文献类型：
--
作者：
Ding, Shiming;Chen, Musong;Zhang, Chaosheng
沉积物中磷的内负荷在有害藻华的季节性氮限制中起着重要作用，但缺乏实验证据。本文以太湖一个大型浅水湖泊为研究对象，通过为期一年的野外采样（2016年2月至2017年1月），研究了湖泊内部磷对氮限制的贡献。一个prebloom-bloom期间确定从2月至8月根据在水柱中的叶绿素a浓度的增加，在此期间，总氮与总磷（TN TP）的比例随月呈指数下降，从43.4至7.4。高分辨率透析（HR-Peeper）和薄膜扩散梯度（DGT）分析显示，沉积物中移动的P（SRP和DGT-labile P）的垂直分布变化很大，导致沉积物-水界面处的SRP扩散通量范围为0.01至6.76 mg/m2/d（负号表示向下通量）。SRP与孔隙水中可溶性Fe（11）浓度之间存在显著的线性相关关系，反映出移动的P的时空变化受微生物介导的Fe氧化还原循环控制。质量估计表明，沉积物中的SRP的累积通量占54%的增加，在水华前期观察到的水柱中的TP。沉积物SRP通量与水体TN/TP呈显著负相关（p <0.001）。总体而言，这些结果提供了坚实的证据，内部磷负荷的主要作用，造成氮限制在开花前开花期。(C)2018 Elsevier B. V.版权所有。
It is proposed that the internal loading of phosphorus (P) from sediments plays an important role in seasonal nitrogen (N) limitation for harmful algal blooms (HABs), although there is a lack of experimental evidence. In this study, an ecarophic bay from the large and shallow Lake Taihu was studied for investigating the contribution of internal P to N limitation over one-year field sampling (February 2016 to JanuaTy 2017). A prebloom-bloom period was identified from February to August according to the increase in Chla concentration in the water column, during which the ratio of total N to total P (TN TP) exponentially decreased with month from 43.4 to 7.4. High-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) analysis showed large variations in the vertical distribution of mobile P (SRP and DGT-labile P) in sediments, resulting in the SRP diffusion flux at the sediment-water interface ranging from 0.01 to 6.76 mg/m2/d (minus sign denotes downward flux). Significant and linear correlations existed between SRP and soluble Fe(11) concentrations in pore water, reflecting that the spatial-temporal variation in mobile P was controlled by microbe-mediated Fe redox cycling. Mass estimation showed that the cumulative flux of SRP from sediments accounted for 54% of the increase in TP observed in the water column during the prebloombloom period. These findings are supported by the significantly negative correlation (p 001) observed between sediment SRP flux and water column TN/TP during the same period. Overall, these results provide solid evidence for the major role of internal P loading in causing N limitation during the prebloom-bloom period. (C) 2018 Elsevier B.V. All rights reserved.