Comparative phosphorus sorption by marine sediments and agricultural soils in a tropical environment.
The influence of soil phosphorus (P) sources on P sorption characteristics of marine sediments was investigated for Pearl Harbor and off shore Molokai in Hawaii. Estuary sediments were sampled in seven locations; these represented different soils and on-shore activities. The soil samples included nine major soils that contributed sediment to the Harbor and coastal sediments near the island of Molokai. Sediment and soil samples were equilibrated for 6 days in 0.01 M CaCl(2) solution and synthetic seawater containing differing amounts of P. Phosphorus sorption curves were constructed. The equilibrated solution P, with no P added, ranged from 0.01 to 0.2 mg L(-1); P sorption by sediments at standard solution concentration 0.2 mg L(-1), ranged from 0 to 230 mg kg(-1). Sediment P sorption corresponded closely with soil sorption characteristics. Soils contributing sediments to the west reach of Pearl Harbor are highly weathered Oxisols with high standard P sorption values while those in the southeast of the Harbor were Vertisols and Mollisols which sorb little P. The influence of source materials on sediment P sorption was also observed for off-shore sediments near Molokai. Sediments serve as both source and sink for P in Pearl Harbor and in this role can be a stabilizing influence on P concentration in the water column. Phosphorus sorption curves in conjunction with water quality data can help to understand P dynamics between sediments and the water column and help evaluate concerns about P loading to a water body. For Pearl Harbor, solution P in equilibrium with sediments from the Lochs was 0.021 mg L(-1); a value unlikely to produce an algal bloom. (Measured total P in the water columns (mean) was 0.060.).
Fox
Robert L
RL
Department of Natural Resources and Environmental Management, University of Hawai'i at Manoa, Honolulu, HI 96822, USA.
Fares
Ali
A
Wan
Y
Y
Evensen
Carl I
CI
D000327:Adsorption; D000383:Agriculture; D004784:Environmental Monitoring; D005068:Eutrophication; D019015:Geologic Sediments / Q000737:chemistry*; D006254:Hawaii; D006863:Hydrogen-Ion Concentration; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry; D012987:Soil / Q000032:analysis*; D014329:Tropical Climate; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
D012987:Soil; D014874:Water Pollutants, Chemical; D010758:Phosphorus