桂林会仙湿地沉积物中磷形态及分布特征

Forms and distribution of phosphorus in sediments of Huixian Wetland in Guilin

沉积物中磷的含量及其形态是影响水体营养化进程的重要因素,对研究湿地水体富营养化具有重要意义。应用蒋柏藩等石灰性土壤无机磷提取方法,调查了桂林会仙岩溶湿地5个典型区域柱状沉积物中的磷形态分布、垂向上的变化特征,分析了各形态磷之前的相关性。结果表明,桂林会仙湿地柱状沉积物中w(TP)为161.14~555.48 mg/kg,活性较高的Ca2-P(5.27~51.45 mg/kg)、Ca8-P(7.76~37.57 mg/kg)均较低。沉积物中的磷以Ca-P(42.92%)为主,Ca-P中的Ca10-P所占比例较高(>70.3%),导致内源磷不易释放,有利于减缓桂林会仙湿地水体富营养化进程。在空间分布上,Ca2-P、Ca8-P、Al-P、Fe-P与TP分布趋势相似,从沉积物表层至底层逐渐降低并趋于稳定。Pearson相关系数表明,TP与总氮(TN)、有机质(OM)、Ca2-P、Ca8-P、Al-P、Fe-P极显著相关,与Ca10-P显著相关。

The content and forms of phosphorus( P) in sediments are important factors affecting the water eutrophication level and have great significance for study of wetland water and other environmental problems.Distribution and vertical variation of P forms in sediment cores sampled from five representative sites of Huixian Wetland in Guilin,as well as the correlation coefficients between sediment P forms,were studied with the method of sequential extraction of inorganic phosphorus from calcareous soil. Results show that the average total P( TP) content in sediment cores varies from 161. 14 to 555. 48 mg /kg. The contents of Ca2-P( 5. 27 ~ 51. 45 mg / kg) and Ca8-P( 7. 76 ~ 37. 57 mg / kg) with high activity are low. The high content of Ca-P( 42. 92%) in the sediments and the high proportion( > 70. 3%) of inert calcium phosphorus in Ca-P prevent the endogenous phosphorus in sediments from releasing into overlaying water,thus slowing down the water eutrophication process in Huixian Wetland. In spatial distribution,Ca2-P,Ca8-P,Al-P,Fe-P,and TP have the similar trends that their contents all decrease gradually from surface to bottom of sediments and become stability finally. Correlation analysis indicates that TP have a very significant correlation with TN,OM,Ca2-P,Ca8-P,Al-P,Fe-P,and a significant correlation with Ca10-P.