Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH 45221-0012, USA.
Environ Int. 2019 Sep;130:104916. doi: 10.1016/j.envint.2019.104916. Epub 2019 Jun 19.
In this work, the distribution of organic phosphorus (P) species in sediment profiles of five shallow lakes was analyzed and its effect on the photo-release of dissolved phosphate (P) was investigated during sediment resuspension under simulated sunlight irradiation. The results show that P was highly enriched in the surface sediment and gradually decreased as sediment depths increased: 33.10 ± 2.55-96.71 ± 7.60 mg/kg, 33.55 ± 2.34-142.86 ± 5.73 mg/kg, 57.50 ± 3.46-149.68 ± 7.67 mg/kg, 55.18 ± 4.67-168.73 ± 8.31 mg/kg, 98.75 ± 7.56-275.74 ± 10.70 mg/kg for Lake Hou, Lake Tuan, Lake Tangling, Lake Guozheng and Lake Miao, respectively. The photo-release amount of dissolved P in the resuspension composed of surface sediments was also higher than that of deep sediment during sediment resuspension under the simulated sunlight irradiation for 9 h. The potential reasons for these results are: (1) difference in morphology and composition of sediments at different depths: the mean particle size of sediment decreased first and then increased as sediment depths increased; (2) difference in composition of P species with depths in the sediment profiles: more photolytic P species existed in surface sediments confirmed by sequential extraction and P NMR analysis; and (3) more OH production in the resuspension composed of surface sediment under simulated sunlight irradiation, which directly influence the photo-release of dissolved P from photodegradation of organic phosphorus. All of these results indicate that the distribution of organic phosphorus species in the sediment profiles plays an important role in P cycle and its photodegradation during sediment resuspension may be one of the potential pathways for phosphate supplement in shallow lakes.
在这项工作中，分析了五个浅湖沉积物剖面中有机磷（P）形态的分布，并在模拟阳光照射下沉积物再悬浮过程中研究了其对溶解磷酸盐（P）光释放的影响。结果表明，P 在表层沉积物中高度富集，并随着沉积物深度的增加而逐渐减少：33.10±2.55-96.71±7.60mg/kg、33.55±2.34-142.86±5.73mg/kg、57.50±3.46-149.68±7.67mg/kg、55.18±4.67-168.73±8.31mg/kg、98.75±7.56-275.74±10.70mg/kg，分别为湖后、团湖、唐陵湖、郭正湖和苗湖。在模拟阳光照射下再悬浮 9 小时后，表层沉积物组成的再悬浮中溶解 P 的光释放量也高于深层沉积物。造成这些结果的潜在原因有：（1）不同深度沉积物的形态和组成存在差异：沉积物的平均粒径先减小后增大；（2） 沉积物剖面中磷形态的组成随深度的差异：通过顺序提取和 P NMR 分析，表层沉积物中存在更多的光解磷形态；（3）在模拟阳光照射下，由表层沉积物组成的再悬浮中产生更多的 OH 产物，这直接影响有机磷光降解过程中溶解 P 的光释放。所有这些结果表明，沉积物剖面中有机磷形态的分布在 P 循环中起着重要作用，在沉积物再悬浮过程中，其光降解可能是浅湖磷酸盐补充的潜在途径之一。
