Biogeochemistry of microbial necromass in mangrove soils: implications for organic carbon sequestration and stabilization

• Grant number: 25/13911-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: July 31, 2029
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Tiago Osório Ferreira
• Grantee: Raissa Razera
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON), AP.CEPID

Abstract

Mangroves are coastal ecosystems characterized by high primary productivity, intense biogeochemical dynamics, and organic carbon accumulation in anoxic environments. Their ability to sequester carbon over the long term, conserve biodiversity, and provide essential ecosystem services positions them as strategic elements for achieving the Sustainable Development Goals (SDGs) and mitigating climate change. Mangrove soils develop from allochthonous sediments deposited in an estuarine environment, whose composition reflects the geology of the contributing basins. A key component in soil carbon stabilization is microbial necromass, which remains largely unexplored in Brazilian mangroves. Given that regional lithology strongly influences the mineralogy of mangrove soils, this research hypothesizes that lithology is an implicit factor in SOC stabilization, determining mineralogical and microbiological composition. To test this hypothesis, this research project will use a Brazil-wide approach, using representative samples of pristine mangroves from each of the four regions of the Brazilian coast (North, Northeast, Southeast, and South). Laboratory analyses will include the quantification of carbon in the different compartments: total soil organic carbon (SOC), particulate organic carbon (POC), mineral-associated organic carbon (MAOC), and microbial necromass carbon. Furthermore, the composition, structure, and diversity of mangrove soils will be assessed through sequencing of the 16s rRNA gene (bacteria) and the ITS region (fungi). The results obtained in this study will provide the basis for understanding the carbon dynamics of Brazilian coastal mangroves and the role of lithology, revealing priority areas for conservation and climate change mitigation.