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您的检索式：作者名="Temporetti PEDRO"
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| 1 | Dynamics of phosphorus in sediments of a naturally acidic lake显示文摘The mechanisms which controls the fixation and/or release of P in sediment of an extremely acidic lake(pH = 2.0 to 3.0) and its response to the influence of eutrophic urban waste water were investigated.The results,in the chemical composition,in the mineralogy of the sediment and in the material as obtained from sediment traps,show that the lake sediments are mainly volcanic material reflecting volcanic features of the basin.The sedimentation rate calculated for the lake(2.5×10^(-2) mg m^(-2) day^(-1)) was higher than that observed in other similar glacial lakes in both Andean Patagonia and also elsewhere in the world.The Total Phosphorus concentration in sediments was higher than figures reported by other authors for mining acid lakes,and the main fraction of P was found associated with organic matter.There was no control by Fe or Al on P,because both are in solution at pH < 3.0.It was concluded that changes in the natural input of nutrients(derivatives of Copahue volcano fluid,the discharge of sewage,or basin run-off) are responsible for a high concentration of SRP and N-NH_4^+ in the lake.Laboratory experiments showed that sediments have no ability to retain phosphorus and a continuous release of P from the sediments into the water column was observed.The assays where the pH was artificially increased showed that the P still remains in solution until at least pH 7.0.It was concluded that changes in the natural input of nutrients due to:1) the volcanic fluids,2) the increase in sewage charges,or 3) surface runoff upstream,maintain a high trophic state with high concentrations of dissolved P and N-NH_4^+,although the threshold of neutral pH in the lake is exceeded.This study will enable a better understanding about of the mechanism of release/fixation of phosphorus in acidic sediments in order to assist in making decisions regarding the conservation and management of this natural environment. | Temporetti PEDRO Snodgrass KIMBERLEY Pedrozo FERNANDO | 2013 | International Journal of Sediment Research2013，28，1： | 6 |
| 2 | Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes显示文摘Phosphorus(P) fractionation and sorption behavior were studied in the sediments of two calcium-sulfate(Ca-SO_4: Ca^(2+)170 mg L^(-1); SO_4^(2-) 400 mg L^(-1)) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir(ECR),which stratifies in summer and El Nihuil Reservoir(ENR),which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location: ECR(downstream from a valley adjacent to a mountain environment) had higher clay proportions while the sand fraction was more important in ENR(just next to a mountain environment).In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high(1.1-1.6 mg P kg^(-1) dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P(ECR, 69% and ENR, 63%) followed by organic-P(23%)in summer-anoxic ECR and by iron/aluminum(Fe/Al)-P(27%) in oxic ENR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in ENR that model fitted only at low dissolved P values(<5 mg PL^(-1)) and co-precipitation evidence was observed at higher P concentrations. It is proposed that lower Fe/Al-P content in anoxic(ECR) vs. oxic(ENR) sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron,and ENR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reservoir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology. | José Gabriel León Fernando Luis Pedrozo Pedro Félix Temporetti | 2017 | International Journal of Sediment Research2017，32，3： | 3 |
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