Water, sediment and soil physicochemical interactions in freshwater, brackish and saline systems

The physicochemical interactions between water, sediment and soil deeply influence the formation and development of the ecosystem. In this research, different freshwater, brackish and saline subaqueous environments of Northern Italy were chosen as study area to investigate the physicochemical processes which occur at the interface between water and sediments, as well as the effects of soil submergence on ecosystem development. In the freshwater system of the Reno river basin, the main purpose was to define the heavy metals hazard in water and sediments of natural and artificial water courses. Heavy metals partitioning and speciation allowed to assess the environmental risk linked to the critical action of dredging canal sediments, for the maintenance of the hydraulic safety of plain lands. In addition, some bioremediation techniques were experimented for protecting sediments from heavy metals contamination, and for giving an answer to the problem of sediments management. In the brackish system of S. Vitale park, the development of hydromorphic and subaqueous soils was investigated. The study of soil profiles highlighted the presence of a soil continuum among pedons subjected to different saturation degrees. This investigation allowed to the identification of both morphological and physicochemical indicators, which characterize the formation of subaqueous soils and describe the soil hydromorphism in transitional soil systems. In the saline system of Grado lagoon, an ecosystem approach was used to define the role of water oscillation in soil characterization and plants colonization. This study highlighted the close relationship and the mutual influence of soil submergence and aeration, tide oscillation and vegetation cover, on the soil development. In view of climate change, this study contribute to understand and suppose how soil and landscape could evolve. However, a complete evaluation of hydromorphic soil functionality will be achieved only involving physiological and biochemical expertise in these kind of studies

PRELIMINARY RESULTS ON ENZYMATIC ACTIVITIES IN TWO SALT MARSH SOILS DIFFERING IN HYDROMORPHIC CHARACTERISTICS AND VEGETATION COVER

Salt marsh soils are characterized by temporary hydric saturation and by vegetation cover that is dominated by different salt-tolerant plant species depending on factors such as duration of submersion. The composition of microbial communities is an essential component of trophic dynamics and biogeochemical processes in salt marshes and determines the activities of enzymes that catalyze the conversion of complex molecules into simpler ones. However, enzymatic activities have not yet been investigated in salt marsh soils. The aim of this study was to analyze the activities of some oxidoreductase and hydrolase enzymes in two salt marsh soils affected by different levels of water saturation and covered by vegetation dominated by different plant species [Juncus maritimus Lam and Spartina maritima (Curtis) Fernald]. The enzyme activities were measured both in air-dried (only) and in air-dried, re-moistened soil samples. The activities in soils under both types of vegetation were much lower than usually found in terrestrial ecosystems. However, in the air-dried samples, the enzyme activities were higher in the soil under Juncus than in the soil under Spartina and tended to decrease with depth, particularly in the former. The activities of all enzymes considered tended to be higher, throughout the whole soil profile, in the re-moistened than in the air-dried soils, especially in the soil under Spartina. Hydrolase activity was strongly and positively related to organic matter content in both air-dried and re-moistened soil samples, particularly in the latter. By contrast, oxidoreductase activity was generally only related to organic matter content in the re-moistened soil samples. Further studies, preferably with freshly collected soil samples, are required to clarify the relationship between enzymatic activities and environmental conditions

Technosols Development in an Abandoned Mining Area and Environmental Risk Assessment

none4noThe study of Technosols development, spatial distribution and physicochemical characteristics is becoming more and more important in the Anthropocene Era. The aim of the present study was to assess soil features and potential heavy metal release risk of soils developed on different mine tailing types after the waste disposal derived from mining activity in Central Italy. Soils were analyzed for their morphological, physical and chemical properties, and a chemical sequential extraction of heavy metals was performed. The investigated soils were classified as Technosols toxic having in some layer within 50 cm of the soil surface inorganic materials with high concentrations of toxic elements. Our findings showed that the bioavailability of potentially toxic element concentrations in the soil changed according to the origin of the mine tailing. However, because of the acidic pH, there is a serious risk of metals leaching which was reduced where the soil organic matter content was higher.openFerronato, Chiara; Vianello, Gilmo; Feudis, Mauro De; Vittori Antisari, LiviaFerronato, Chiara; Vianello, Gilmo; Feudis, Mauro De; Vittori Antisari, Livi

Soil properties and plant community relationship in a saltmarsh of the Grado and Marano lagoon (northern Italy)

7noPurpose: The relationship between soil properties and plant communities was investigated in a saltmarsh of the Grado and Marano lagoon (northern Italy), where hydrology and micromorphology strongly influence the features of the ecosystem. A multidisciplinary approach was used to assess the change of soil properties and plant communities in relation to the submergence of soil. Materials and methods: The plant community and soil profile surveys were both carried out along a transect in six sampling sites of the Gran Chiusa saltmarsh (Grado and Marano lagoon). The morphological and physicochemical parameters of soil profiles were investigated, and soils were classified according to Soil Taxonomy. The concentration of macronutrients in both soils and plants was analysed by inductively coupled plasma-optical emission spectrometry. Cluster and linear discriminant analysis were used to assist the interpretation of the data of plant communities and soil properties, respectively. The bioconcentration factor explored the macronutrient relationship between plant community and soil. Results and discussion: A high, middle and low zone were identified by clustering the different plant communities along the studied transect. Discriminant analysis showed how the increase in soil submergence supported the accumulation of S and Ca content and depletion of Fe and Na. The development of different plant communities was linked to both soil water saturation and to the capacity of halophytes to tolerate anoxic conditions or salinity, by extrusion or bioconcentration strategies. Conclusions: This study demonstrates that tide level plays an important role in the pedological development and chemical transformations along a soil hydrosequence. The micromosaic vegetation pattern may therefore represent a useful index of the hydrological and nutritional status of the underlying soils and could be used to predict changes in coastal ecosystems. © 2016, Springer-Verlag Berlin Heidelberg.openopenVittori Antisari, Livia; Ferronato, Chiara; Pellegrini, Elisa; Boscutti, Francesco; Casolo, Valentino; de Nobili, Maria; Vianello, GilmoVittori Antisari, Livia; Ferronato, Chiara; Pellegrini, Elisa; Boscutti, Francesco; Casolo, Valentino; DE NOBILI, Maria; Vianello, Gilm

The development of a microbial metal - resistance consortium for metal bioremediation in a simulated fluvial system

Our main goal was to enrich the microbial population which develops when a pollution event changes the equilibrium of a fluvial system and thereafter investigate the effectiveness of this adapted bacterial consortium in a simulated bio-remediation process. The contaminated soil of a highly heavy metal polluted mining deposit was mixed with non-contaminated fluvial sediment in a ratio of 1:3. After the addition of fresh fluvial water, the system was allowed to equilibrate for one month. Then, a research was carried out on experimental microcosms in order to test the effects of the surviving microorganisms on toxic heavy metals (Cu, Fe, Zn) that are polluting surface sediments. The adapted microbial population was first enriched in aerobic conditions with a high concentration of heavy metals (up to 300 mg/l Cu; 400 mg/l Fe; 600 mg/l Zn) and afterwards the consortium obtained was applied in a microcosm to test its effect on the decontamination of heavy metals. The study has demonstrated that some microorganisms can survive the contamination. However, with regard to the tested metals, the microorganisms did not influence the status of the metals during the period of the analysis

The development of a microbial metal - resistance consortium for metal bioremediation in a simulated fluvial system

Our main goal was to enrich the microbial population which develops when a pollution event changes the equilibrium of a fluvial system and thereafter investigate the effectiveness of this adapted bacterial consortium in a simulated bio-remediation process. The contaminated soil of a highly heavy metal polluted mining deposit was mixed with non-contaminated fluvial sediment in a ratio of 1:3. After the addition of fresh fluvial water, the system was allowed to equilibrate for one month. Then, a research was carried out on experimental microcosms in order to test the effects of the surviving microorganisms on toxic heavy metals (Cu, Fe, Zn) that are polluting surface sediments. The adapted microbial population was first enriched in aerobic conditions with a high concentration of heavy metals (up to 300 mg/l Cu; 400 mg/l Fe; 600 mg/l Zn) and afterwards the consortium obtained was applied in a microcosm to test its effect on the decontamination of heavy metals. The study has demonstrated that some microorganisms can survive the contamination. However, with regard to the tested metals, the microorganisms did not influence the status of the metals during the period of the analysis

Technosols Development in an Abandoned Mining Area and Environmental Risk Assessment

The study of Technosols development, spatial distribution and physicochemical characteristics is becoming more and more important in the Anthropocene Era. The aim of the present study was to assess soil features and potential heavy metal release risk of soils developed on different mine tailing types after the waste disposal derived from mining activity in Central Italy. Soils were analyzed for their morphological, physical and chemical properties, and a chemical sequential extraction of heavy metals was performed. The investigated soils were classified as Technosols toxic having in some layer within 50 cm of the soil surface inorganic materials with high concentrations of toxic elements. Our findings showed that the bioavailability of potentially toxic element concentrations in the soil changed according to the origin of the mine tailing. However, because of the acidic pH, there is a serious risk of metals leaching which was reduced where the soil organic matter content was higher

Antropocene e dintorni

Raccolta di schede sul tema, scelte e curate da Chiara Continisio e Marta Ferronat