Characteristics of bioavailable organic phosphorus in sediment and its contribution to lake eutrophication in China.
This study aims to establish the relative importance of sediment organic phosphorus (Po) to the total P and the major classes of organic molecules that contribute to sediment Po, determined by measuring their susceptibility to enzymatic hydrolysis, across a suite of lakes ranging from oligotrophic to eutrophic status. The results showed that Poaccounted for 21-60% of total P, and bioavailable Poaccounted for 9-34% of Poin the sediments. The bioavailable Poincludes mainly labile (H2O-Po) and moderately labile (NaOH-Po) P forms. For H2O-Po(accounting for only1.4% of Po), 53% (average) was labile monoester P, 28% was diester P and 17% was phytate-like P. For NaOH-Po(accounting for 9-33% of Po), 32% was labile monoester P, 33% was phytate-like P and 18% was diester P. The composition of bioavailable Po, determined by enzyme assays, was related to the lake nutrient levels, which implies that sediment bioavailable Pocould act as an effective indicator for lake eutrophic status. With the increase of lake nutrient levels, bioavailable Pocontent and alkaline phosphatase activity in the sediment all increased, indicating that Porepresents an important and bioavailable source of P that increases with eutrophication, and could contribute to internal loading and resistance of eutrophic lakes to remediation. This implies that eutrophic lakes would maintain long-term eutrophic status and algal bloom phenomena even after the external input of P was controlled and the total P concentration of water has declined. Thus, in order to reduce the release risk of sediment P more efficiently and effectively, sediment P control technique should focus not only on reducing the total P and inorganic P, but should also pay close attention to the removal of bioavailable Po.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Dongting Lake Ecological Observation and Research Station, Yueyang, 414000, China.
Zhaokui
Z
Ni
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Dongting Lake Ecological Observation and Research Station, Yueyang, 414000, China. Electronic address: wangsr@craes.org.cn.
Shengrui
S
Wang
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Resource Environment and Tourism, Capital Normal University, Beijing, 100048, China.
Yuemin
Y
Wang
D002681:China; D005068:Eutrophication; D019015:Geologic Sediments / Q000737:chemistry*; D006868:Hydrolysis; D060106:Lakes / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D010758:Phosphorus
Bioavailability; Contribution; Organic phosphorus; Sediment