Suspended particulate matter in Jiaozhou Bay: Properties and variations in response to hydrodynamics and pollution

Based on water samples collected and observations of currents, tidal levels as well as turbidities taken, respectively over a period of 15 and 7 d, in southwestern Jiaozhou Bay on August, 2001, it was found that: (i) the average content of non mineral component amounted to 87% of the suspended sediment matter (SPM) in Jiaozhou Bay, much higher than in estuaries and bays where turbidity is high and mineral particulates dominates; (ii) in contrast to high turbid bays, SPM was generally coarser than bed deposits and in upper water column than in lower water column in Jiaozhou Bay; (iii) in fair weathers, suspended sediment concentration (SPC) varied regularly within tidal cycles and neap-spring cycles, but the regularity was deformed in storms; and (iv) SPC was controlled by settling/resuspension near the bed and by advection at the surface at the study site with a depth of 20 m, suggesting weak vertical exchanges. It was concluded that SPM property of a low turbid bay is sensitive to pollution, and that the maintenance of low turbidity in the bay depends on less SPM supply, low waves and currents, and controlling on discharge of particulate pollutants.