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This past June, from 23-28, the 8th International Symposium on Interactions of Soil Minerals with Organic Components and Microorganisms was held in the city of Seville. This symposium was organized by Division 2.5 belonging to the International Union of Soil Sciences (IUSS). The specific theme chosen for this symposium was “Understanding Soil Interfacial Reactions for Sustainable Soil Management and Climate Change Mitigation”.

From the INTARSU Project we had the opportunity to participate in this symposium in the scientific session entitled “Dynamics of pollutants at soil interfaces – What is new and how can environmental biotechnology be beneficial for soil restoration and bioremediation?”

Marta Gil Martínez gave an oral presentation entitled “Tree species effect on soil organic matter and soil microorganisms in trace element contaminated soils” where she presented the latest results obtained from the study about the effects of phytoremediation in soils contaminated by trace elements, after the mining spill of Aznacólllar in 1998. In this study, an exhaustive study of the changes in soil organic matter was carried out under three tree species: olive, white poplar and pine, and in a treeless area dominated by herbaceous species. In addition, two zones located 15 and 30 km from the discharge point were sampled to study, as well as, how the effects of these trees vary according to the physical and chemical properties of the soils.

The objectives of this study were:

- Evaluating the effect of these species on different fractions of soil organic matter, after 15 years of tree growth, as part of the phytoremediation program.

- Analysing the influence of microbial activity in two contrasted areas with different degradation status.

The results obtained from this study showed that the North zone (closer to the mine) has greater availability of trace elements due to the acidic pH and the low content of soil organic matter. Among the species studied, the pine had an acidifying effect in this zone but not in the South zone (farther from the mine) due to the neutral pH and greater buffering power of these soils. This effect of the pine is explained by infrared analysis, which showed its litter and underneath soils some characteristic peaks of acidic functional groups (pectins, resins and waxes), which did not appear in other species infrared analysis.

The effects of phytoremediation had a positive effect on the amount of organic matter, compared to treeless areas, and this was reflected in a greater microbial biomass.

Among the conclusions of this study, we highlight the potential of pine trees to acidify the soil, however this species also generates a large amount of litter, increasing the organic matter of the soil. It has also been found that reforestation has increased microbial biomass, therefore, new functionalities are being recovered in soils.

You can access the presentation in this link:

Gil-Martínez M, Fernández Boy ME, Marañón T, Montero González JF, Navarro-Fernández CM, Domínguez MT (2019). Tree species effect on soil organic matter and soil microorganisms in trace element contaminated soils. 8th International Symposium on Interactions of Soil Minerals with Organic Components and Microorganisms (Sevilla).

The Iberian Ecological Society SIBECOL has just been established to gather professional scientist from Portugal and Spain from all ecology areas: theoretical, terrestrial, marine and continental waters. Its main aim is promoting ecology and to give visibility to scientific works in all these fields.

To celebrate the establishment of the society and to share the scientific progress in ecology, last 4th -7th of February the First SIBECOL Congress, as well as the XIV AEET Meeting, were celebrated. The venue selected was the Faculty of Biology at the University of Barcelona (Spain).

This congress was celebrated in an emblematic time and place due to the commemoration, this year 2019, of the centenary of Professor Ramon Margalef. Margalef became one of the most relevant ecologist of the XX century and the first professor of Ecology in Spain at the University of Barcelona, where all the Iberian ecologist had the opportunity to meet.

INTARSU Project did not want to miss this important event for ecology and we had the opportunity of presenting our last study in a poster titled: “Phytostabilisation of trace elements with different tree species revealed a species-specific effect on soil functioning”. This work has been possible thanks to the collaboration between researchers from IRNAS-CSIC, University of Sevilla and University of Reading (United Kingdom). The poster was presented in the Thematic Session 14 “Organisms and ecosystem responses to global change in soils and sediments”, organized by the Group of Plant-Soil Interactions of AEET.

In this study, we presented the effects of different tree species (white poplar, wild olive and stone pine) on biotic and abiotic soil properties. The study area, known as Guadiamar Green Corridor (Seville), suffered in 1998 a serious contamination due to Aznalcóllar mine-spill. After a remediation plan in the whole affected area, different tree and shrubs species were planted, and 15 years after these trees have generated soil changes. In relation to soil nutrients, we have found that the tree coverage has increased fertility in soils underneath compared to soils covered by herbaceous plants. Among the studied species, white poplar trees have helped to neutralize soil pH; however, stone pine trees have acidified the soil which is undesirable as acidity increases soil trace element availability. Soil microbial activity presented differences among tree species and we found that enzyme activities with an important role in C, N and P cycles were highly dependent on soil pH. To summarise, we have found a tree species effect on abiotic and biotic soil properties with direct consequences on soil functioning.

Gil-Martínez, Marta; Domínguez, María Teresa; Navarro-Fernández, Carmen María; Tibbett, Mark; Marañón, Teodoro (2019). Phytostabilisation of trace elements with different tree species revealed a species-specific effect on soil functioning. In: Abstract book. 1st Meeting of the Iberian Ecological Society & XIV AEET Meeting. Ecology: an integrative science in the Anthropocene. February 4-7, 2019, Barcelona (Spain), page 269. AEET, Madrid, DOI: 10.7818/SIBECOLandAEETmeeting.2019.