The cyanobacteria have an evolutive history counting about 3.5 billion years and, along this long evolutive pathway, conquered adaptations resulting in a great capacity of ecological and geographical distribution. Among the places where they are settled, cyanobacteria can inhabit different kinds of soils and are notable for integrate the "biological crusts". In these communities, they assume important ecological roles, such as primary producers, aggregators of soil particles, nitrogen and carbon fixers, as well as contributors to increase and maintain soil moisture. Even with recognized importance, studies with biologic crust cyanobacteria in Brazil are limited to some areas of the Brazilian savannah (cerrado), semiarid formations (caatinga) and southern grassland (pampa), with no studies involving crusts from more complex forested areas. The seasonal semideciduous forest is a more interior vegetational type derived from costal tropical rainforest (mata atlântica) that occurs in a wide area of the State of São Paulo and is well adapted to the inland environment. Due to disturbances by anthropic activities, this vegetation has been greatly impacted and the original areas fragmented. The edges of such fragments generally constitute an environment of characteristics hostile to many organisms, but they offer conditions to the installation of biological crusts. Considering the characteristics of these organisms and the wide distribution and fragmentation of the semideciduous seasonal forest of the northwest of the state of São Paulo, the present project proposes the survey of the diversity of cyanobacteria in crusts using a polyphasic approach. Five fragments of semideciduous seasonal forest in the region of São José do Rio Preto will be evaluated and crusts will be sampled at three different points in each area. From the collected material, morphological studies will be carried out and artificial cultures will be established aiming, after isolation, the genetic analysis of the different populations comparing their 16S rRNA gene. The ecological data (occurrence, habitat), morphological and molecular data will be assembled to identify the taxa found. In addition, the influence of selected environmental parameters (temperature, soil moisture, texture and nutrients) on the occurrence and distribution of cyanobacteria species will be evaluated. Thus, this study will contribute to increase the knowledge of an important group of organisms and will collaborate with the addition of new information on fragments of semideciduous seasonal forest, which is a vegetational type currently very impacted.
News published in Agência FAPESP Newsletter about the scholarship: