英国Culm河河漫滩沉积物中磷素时空变化研究

SPATIO-TEMPORAL VARIATION OF THE ACCUMULATION OF SEDIMENT-ASSOCIATED PHOSPHORUS ON THE FLOODPLAIN OF THE RIVER CULM, DEVON,UK

河漫滩上沉积物的沉积伴随着与沉积物相结合的营养和污染物质的沉积。已有研究表明,河漫滩是与沉积物相结合的磷的沉积地。采用137Cs技术,并结合河漫滩沉积物中全磷(TP)含量的剖面信息,可以调查近年河漫滩沉积物中的TP含量,计算TP储量。本文根据英国Devon郡Culm河8个河漫滩采样环沉积物中的数据,重建了在过去40～50年内TP储量和含量的变化。结果表明,在Culm河河漫滩沉积物中,在1963～2000年间TP平均含量为0.60～1.96gkg-1,该值自河流上游向下游和自过去到现在有逐渐增加的趋势;在相同的河漫滩沉积物中,在相同的时期内TP储量为18.62～435.48gm-2,即0.49～11.46gm-2a-1,最大值出现在河流的中游。

Deposition of sediments on river floodplains is accompanied by the deposition of sediment-associated nutrients and pollutants. Using the 137Cs measurement to provide a chronology for sediment cores, in combination with information on downcore variations of the total-P content of floodplain sediment cores, affords a means of investigating recent changes in the total-P content of the suspended sediment deposited on the river floodplains and of documenting recent rates of phosphorus accumulation. Results are presented for sediment cores collected from eight floodplain reaches of River Culm, Devon, UK. The average values of total-P concentration of fine sediment deposited since 1963 for individual cores range from 0.60 to 1.96 g kg -1, and the values of total-P storage since 1963 range from 18.6 to 435 g m -2, showing a trend of total-P concentration increasing from upstream to downstream and from the 1960s to the present.