Dissolved organic matter composition modulated by microbial communities, hydrology and temperature

• Grant number: 24/11118-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: January 01, 2025
• End date: February 28, 2026
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Hugo Miguel Preto de Morais Sarmento
• Grantee: Israel Cassiano de Oliveira
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The metabolism and structure of communities and ecosystems are the result of a mutual influence between organisms and the environment. In this scenario, carbon flows and balances take center stage by influencing both environmental conditions (e.g. climate, pH and light availability) and microbiome composition and functioning (through trophic interactions and photosynthesis and respiration rates). Freshwater environments function as reactors, sedimenting and emitting carbon of terrestrial origin through processes in which the microbiota and dissolved organic matter (DOM) emerge as key figures in a close relationship of reciprocal influence. Furthermore, these dynamics are strongly subject to environmental factors, especially climatic and hydrological, making up a complex and yet understood system of interactions, especially in tropical waters, where carbon emissions are generally high. The aim of this study is to investigate associations between changes microbial network and DOM composition, mediated by environmental factors. A 5-year time series of monthly data collected in a reservoir (Represa do Broa, Itirapina-SP) will be used. Correlation networks integrating the communities of protozoa, bacteria, phyto- and zooplankton (accessed by microscopy and metabarcoding) will be built and tested against meteorological and hydrological data and the characterization of the MOD (by fluorescence spectroscopy). We hope that changes in water residence time and temperature will initiate feedback cascades between the MOD and microbiome, resulting in changes in the composition of both compartments. With this, we aim to strengthen and contribute to the debate on community structuring processes related to the global carbon balance.