Paleoenvironmental reconstruction of Holocene peatlands in the lower Ribeira do Iguape river - SP

• Grant number: 24/02144-4
• Support Opportunities: Regular Research Grants
• Duration: July 01, 2024 - June 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Convênio/Acordo: CNPq
• Principal Investigator: Pablo Vidal Torrado
• Grantee: Pablo Vidal Torrado
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 23/04708-0 - Peatlands origin and its spatial distribution in the lower Ribeira do Iguape River (SP) and their potential as C sink and greenhouse gases emision, AP.R
• Associated scholarship(s): 24/14874-7 - Paleoenvironmental reconstruction of Holocene peatlands in the lower Ribeira do Iguape River, São Paulo., BP.JD

Abstract

Peatlands are humid ecosystems made up predominantly of Histosols, which are formed by maintaining unfavorable conditions for the decomposition of organic matter. They play an important role in terms of ecosystem functions, such as storing large stocks of carbon, since they correspond to only 3% of the earth's surface, but store a third of the carbon of all soils. Apparently, in the lower Ribeira do Iguape River (BRRI) in the state of São Paulo (SP), Histosols occupy around 70,000 ha, making it one of the largest areas of occurrence of these soils on the South American continent. In a recent pilot study (the proponent's doctoral thesis) conducted in the Campina do Encantado State Park (PECE), in the municipality of Pariquera-Açu (SP), the research team developed and applied advanced protocols for sampling, characterizing and mapping organic soils for different types of studies. Based on this experience, FAPESP submitted and approved Research Grant 2023/04708-0, which will fund the activities proposed here. It is proposed to continue the paleoenvironmental reconstitution studies in other peatlands of the BRRI (one of the objectives of the Research Grant project), with the aim of understanding whether these peatlands were formed in estuarine-fluvial and/or fluvial-continental environments. In addition, the aim is to contribute to understanding the influence of relative sea level variation on the formation of Holocene peat bogs on the southern coast of the state of São Paulo. The hypothesis is that the BRRI peatlands are Holocene and were formed after the beginning of the last marine regression, predominantly under fluvial influence. The brackish environment in which paludization occurred must have been gradually replaced by fresh water over time. The vegetation and genesis of the Histosols appear to be conditioned by a gradient of these conditions from the continent to the coastline. The history of the peat bogs will be reconstructed through the integration of indicators, including their relationship with shell-middens, pollen grains, algae, diatoms, dinoflagellates, palynophoraminifer, ´13C and ´15N isotopes, 14C dating and geochemical analysis of different peatlands distributed in the BRRI. It is hoped that this research will increase understanding of the formation of peatlands in environments close to sea level and their role in the current climate change scenario. (AU)