Iron-carbon interactions in mangrove soils: effect of climate change on carbon sequestration and stabilization

• Grant number: 25/05523-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2025
• End date: February 28, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Tiago Osório Ferreira
• Grantee: Flaviane Caroline Pagoto
• 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 that provide various ecosystem services, including a high capacity to sequester carbon in their soils. However, these ecosystems are among the most affected by climate change, with several predicted environmental impacts, such as sea level rise, reduced freshwater input from the mainland, and increased salinity levels. In this context, understanding the mechanisms involved in carbon sequestration and stabilization in mangrove soils under predicted scenarios is essential for mitigating climate change. Thus, this study aims to investigate the effects of increased salinity on the capacity of mangrove soils with contrasting iron levels to adsorb carbon and on the potential of short-range ordered iron oxides (i.e., ferrihydrite) to adsorb and coprecipitate carbon. To this end, three experiments will be conducted in the laboratory. In the first experiment, soil samples with contrasting iron levels will be incubated under simulated climate change scenarios (increased salinity) and evaluated for their capacity to adsorb organic carbon. In the second and third experiments, ferrihydrite will be subjected to different salinity conditions, and adsorption and coprecipitation assays with organic carbon will be conducted to understand the role of short-range iron oxides in carbon stabilization. Our results will provide insights into how increased salinity may affect the sequestration and stabilization of organic carbon in these coastal ecosystems, in addition to analyzing how the biogeochemical processes that govern the accumulation of organic carbon in mangrove soils respond to climate change. (AU)