Speciation of organic phosphorus in a sediment profile of Lake Taihu. I: Chemical forms and their transformation.
Organic phosphorus (nonreactive P, NRP) is a major component of P in sediments, but information about its chemical forms and dynamic transformation is limited. The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu, a freshwater and eutrophic lake in China, were investigated. Five forms of NRP in the sediments were extracted based on a chemical fractionation technique, including easily labile NRP (NaHCO3-NRP), reactive metal oxide-bound NRP (HCl-NRP), humic acid-associated NRP (NaOH-NRP(HA)), fulvic acid-associated NRP (NaOH-NRP(FA)) and residual NRP (Res-TP). There were notable transformations with increasing sediment depth from the labile NaHCO3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools, which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded. Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP. The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. dxu@niglas.ac.cn
Di
D
Xu
Shiming
S
Ding
Bin
B
Li
Xiuling
X
Bai
Chengxin
C
Fan
Chaosheng
C
Zhang
D005591:Chemical Fractionation; D002681:China; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D060106:Lakes / Q000737:chemistry*; D009930:Organic Chemicals / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry* / Q000302:isolation & purification*; D012972:Sodium Hydroxide / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D012972:Sodium Hydroxide; D006851:Hydrochloric Acid