Research
| Title： | Distribution of organic phosphorus species in sediment profiles of shallow lakes and its effect on photo-release of phosphate during sediment resuspension |
|---|---|
| First author： | Li, Xiaolu; Guo, Minli; Duan, Xiaodi; Zhao, Jianwei; Hua, Yumei; Zhou, Yiyong; Liu, Guanglong; Dionysiou, Dionysios D. |
| Journal： | ENVIRONMENT INTERNATIONAL |
| Years： | 2019 |
| DOI： | 10.1016/j.envint.2019.104916 |
| Abstract： | In this work, the distribution of organic phosphorus (P-o) species in sediment profiles of five shallow lakes was analyzed and its effect on the photo-release of dissolved phosphate (P-i) was investigated during sediment resuspension under simulated sunlight irradiation. The results show that P-o 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-i 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-o species with depths in the sediment profiles: more photolytic P-o species existed in surface sediments confirmed by sequential extraction and P-31 NMR analysis; and (3) more center dot OH production in the resuspension composed of surface sediment under simulated sunlight irradiation, which directly influence the photo-release of dissolved P-i 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. |
