Author/Authors :
Niyazi ، L نويسنده Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Mazandaran, Iran , , Chaichi ، M.J نويسنده Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Mazandaran, Iran , , Najafpour ، S نويسنده Extension Organization (AREEO), Farahabad, P.O.Box 961, Sari, Iran , , Nasrollahzadeh Saravi ، H نويسنده Department of Ecology, Iranian Fisheries Science Research Institute (IFSRI), Caspian Sea Ecology Research Center, Agricultural Research, Education and Extension Organization (AREEO), Farahabad, P.O.Box 961, Sari, Iran , , Norouzi ، M نويسنده Department of Marine Biology and Fisheries Sciences, Tonekabon Branch, Islamic Azad University,Tonekabon, Iran, , , Pourkazemi ، M نويسنده Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and ExtensionOrganization (AREEO). POB:14965-149. Tehran- Iran ,
Abstract :
Seventy Two sediments from four stations (Anzali, Tonekabon, Noshahr and Amirabad), located in Caspian Sea-Iranian coast were examined on the basis of P-fractionation in autumn and winter of 2013-2014. Several forms of the phosphorus in sediment were separated and extracted according to sequential extraction method. Then the extracted phosphorus in each fraction was determined by UV–Vis spectrophotometry. In addition, Total concentrations of Ca, Fe and Al in sediment fractions were also measured by Atomic absorption spectroscopy. In autumn the rank order of P-fractions was: Ca-P > Residual-P > BD-P > Al-P > loosely-P and in winter it was: Ca-P > BD-P > Residual-P > Al-P > loosely adsorbed-P. In both season the loosely adsorbed phosphorus (NH4Cl–P) represented < 1% of the sedimentary inorganic phosphorus, while the reductant phosphorus (BD–P) ranged from 2.7 to 4%. The calcium bound phosphorus (Ca-P or HCl–P) showed considerable contribution (89-91%) to the sedimentary inorganic P-loads. The metal oxide bound phosphorus (Al-P or NaOH–P) was 1.2-1.5% and Residual-P was 2.3-4.5%. Concentration of BD- P increased with increasing depth in all stations and the concentration of other fractions increased in most stations. Sampling seasons had significant effect on variance of most P-fractions and other sediment features. TP and BD-P were positively correlated with Fetot (p < 0.05).
