Five fractions of phosphorus in marine and fluvial surface sediments of Laizhou Bay wereinvestigated by a sequential extraction method. The results indicated that the authigenic calcium-bound phosphorus (ACa-P) in marine sediments (average 45.6%) was higher than that (average 37.3%) in fluvial sediments, but iron-bound phosphorus (Fe-P) in marine sediments (average 18.2%) was lower than that in fluvial sediments (average 31.3%). In coastal zone, a positive correlation was found between exchangeable and loosely sorbed phosphorus (E&L-P) and silt (grain size), indicating that E&L-P was mainly sorbed onto fine particles. A significant correlation (P<0.01) was observed between Fe-P and Fe concentrations in fluvial sediments, which indicates the distribution of Fe-P in fluvial sediments was determined by Fe concentration. The Fe-P concentration in estuary sediments was lower than that in corresponding river sediments. This may be attributed to the input of marine sediments and the reduction of sulfate or the accumulation of sulfide under anaerobic section (Fe fixed by sulfide). The mean values of total extracted phosphorus in sediments presents a decrease trend from offshore to estuaries.
修改评论