Soils preserve and sustain life. Their health and functioning are crucial for crop production and for the maintenanceof major ecosystem services. Human induced salinity is one of the main soil threats that reduces soil fertilityand affect crop yields. In recent times, great attention has been paid to the general shortage of arable land and tothe increasing demand for ecological restoration of areas affected by salinization processes. Despite the diffuseinterest on the effects of salinization on plants’ growth, and all the derived socioeconomic issues, very fewstudies analyzed the ecology of the microbial species in naturally saline soils and the resilience of biologicalfertility in these extreme habitats. Microorganisms inhabiting such environments may share a strategy, may havedeveloped multiple adaptations for maintaining their populations, and cope eventually to extreme conditions byaltruistic or cooperative behaviors for maintaining their metabolism active. The understanding and the knowledgeof the composition and distribution of microbial communities in natural hypersaline soils can be interesting forecological reasons but also to develop new restoration strategy where soil fertility was compromised by naturalaccidents or human mismanagement.The aim of this research was to provide specific information on saline soils in Italy, stressing mainly theirdistribution, the socioeconomic issues and the understanding of the characterizing ecological processes. Moreover,natural saline soils were used as a model for understanding to what extent the concentration of salt can affect somebasic microbial processes.In the present study, physical, chemical and microbiological soil properties were investigated in the shallowerhorizons of natural salt affected soils in Sicily (Italy), where some ecological contrasting variables acted as strongdrivers in fungal and bacterial spatial distribution. Furthermore, the interface between biological and geochemicalcomponents in the surface of that peculiar habitat was investigated to evaluate the organization and diversity of thephototrophic and heterotrophic microorganisms. Sixteen soil samples from A horizons were collected accordingto a random sampling scheme. Bacterial and archaeal communities were characterized by their 16S rDNA geneswith T-RFLP method. A total of 92 genera were identified from the 16S pyrosequencing analysis suggesting thatcyanobacteria and communities of sulfur bacteria might directly or indirectly promote the formation of protectiveenvelope. Some bacterial phyla appeared spread in the whole area, whatever the salinity gradient, while othergroups showed a distribution linked to very compartmentalised soil properties, such as the presence of salinecrusts in the soil surface. Results show that saline soils couldn’t contain just one single microbial communityselected to withstand extreme osmotic phenomena, but many communities that can be variously correlated to oneor more environmental parameters having great importance for the maintenance of the overall homeostasis.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2017|