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Microbial communities and functional genes involved in nutrient cycling in Nhecolândia Wetlands (MS)

Grant number: 17/12644-0
Support type:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): August 01, 2017
Effective date (End): July 31, 2021
Field of knowledge:Biological Sciences - Biochemistry
Principal Investigator:Marli de Fátima Fiore
Grantee:Thierry Alexandre Pellegrinetti
Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Associated research grant:16/14227-5 - Climatic changes and environmental impacts in wetlands of Pantanal region (Brazil): quantification, control factors and long term temporal modeling, AP.PFPMCG.TEM

Abstract

The lakes of the Nhecolândia fluvio-lacustrine system complex, a sub-region of the Pantanal (MS) with water composition varying from freshwater, oligosaline to hypersaline, are considered extreme environments due to the combination of high pH values and high salt concentrations. The determinants of these variations are still not well-defined, despite the various hypotheses about the origin of the salinity of these lakes. Recent research shows that the surface chemistry waters correspond to different stages of Taquari River water concentration, which supports this region. The concentration degree of each lake depends on its water regime, which is controlled by annual fluctuations in water level, but, above all, by the soil systems present around the lakes. Studies conducted in the region show that there are different types of saline lakes (salinas), whose waters may be black, green or crystalline, and that only in those with green water occur bloom with predominance of cyanobacteria, a fact that must be connected to the functioning of this system. Considering the little information about the processes that control the differences in the biogeochemical functioning of salinas, in addition to the climatic factors and the nutrient dynamics (N and P), the objective of this work is to evaluate the bacterial community and to understand the cycles of these elements in these lakes. For this, it will be necessary to: (i) investigate the bacterial community present in the salinas through massive DNA sequencing; (ii) to identify and characterize microbial genes involved in the biogeochemical cycles of nitrogen and phosphorus; (iii) to identify intra and inter-annual variations of pH, electrical conductivity and composition of the elements with higher concentrations in lakes with black and green waters; (iv) to conduct a monitoring of the water level, electrical conductivity and temperature in the lakes selected as experimental areas; (v) perform monitoring of climate conditions (temperature, atmospheric pressure, light intensity, wind speed and direction, precipitation) covering the experimental areas; (vi) to identify variations in water physical-chemical characteristics during 24-hour cycles; (vii) to identify, in 24-hour cycles, nutrient composition variations (NO3-, NH4, Ntotal, PO4) in the waters and; (viii) complete the study with laboratory bioassays. (AU)