Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; Sino-Danish Center for Education and Research, Denmark.
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; Sino-Danish Center for Education and Research, Denmark.
Environ Pollut. 2016 Dec;219:466-474. doi: 10.1016/j.envpol.2016.05.053. Epub 2016 Jul 1.
A thorough understanding of the labile status and dynamics of phosphorus (P) and iron (Fe) across the sediment-water interface (SWI) is essential for managing internal P release in eutrophic lakes. Fe-coupled inactivation of P in sediments is an important factor which affects internal P release in freshwater lakes. In this study, two in-situ high-resolution diffusive gradients in thin films (DGT) techniques, Zr-Oxide DGT and ZrO-Chelex DGT, were used to investigate the release characteristics of P from sediments in a large freshwater lake (Dongting Lake, China; area of 2691 km) experiencing a regional summer algal bloom. Two-dimensional distributions of labile P in sediments were imaged with the Zr-Oxide DGT without destruction of the original structure of the sediment layer at four sites of the lake. The concentration of DGT-labile P in the sediments, ranging from 0.007 to 0.206 mg L, was highly heterogeneous across the profiles. The values of apparent diffusion flux (F) and release flux (F) of P varied between -0.027-0.197 mg m d and 0.037-0.332 mg m d, respectively. Labile P showed a high and positive correlation (p < 0.01) with labile Fe(II) in the profiles, providing high-resolution evidence for the key role of Fe-redox cycling in labile P variation in sediments.
深入了解磷（P）和铁（Fe）在沉积物-水界面（SWI）的不稳定性和动态变化对于管理富营养化湖泊内部 P 释放至关重要。Fe 耦合的沉积物中 P 失活是影响淡水湖泊内部 P 释放的一个重要因素。在本研究中，采用两种原位高分辨率薄膜扩散梯度技术（Zr-Oxide DGT 和 ZrO-Chelex DGT），研究了经历区域性夏季藻类水华的大型淡水湖泊（中国洞庭湖；面积 2691 km）中 P 从沉积物中的释放特征。在湖泊的四个地点，使用 Zr-Oxide DGT 对沉积物中可移动 P 的二维分布进行成像，而无需破坏沉积物层的原始结构。沉积物中 DGT-可移动 P 的浓度范围为 0.007-0.206 mg L，在剖面中高度不均匀。P 的表观扩散通量（F）和释放通量（F）值在-0.027-0.197 mg m d 和 0.037-0.332 mg m d 之间变化。可移动 P 与剖面中的可移动 Fe(II)呈高度正相关（p < 0.01），为 Fe 氧化还原循环在沉积物中可移动 P 变化中起关键作用提供了高分辨率证据。
