Climate and sedimentary dynamics of Amazonian floodplains during the Quaternary and its role on biotic diversification

• Grant number: 22/05520-1
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): January 01, 2023
• Effective date (End): December 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Fernanda Costa Gonçalves Rodrigues
• Host Institution: Escola de Artes, Ciências e Humanidades (EACH). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/23899-2 - Trans-Amazon Drilling Project: origin and evolution of the forests, climate, and hydrology of the South American tropics, AP.PFPMCG.TEM

Abstract

Amazonian fluvial systems play an important role in the biodiversity of the region, as its large rivers create highly dynamic landscapes, transferring sediments from several sources to distant sinks. The distribution and connectivity of different habitats in the Amazonian lowlands are modulated by water and sediment discharge of the Amazon River, that in turn depend on variations in precipitation. Periods of expansion or contraction of floodplains affect biotic dispersal and colonization, leading to hybridization and speciation events, respectively. Thus, reconstructing the response of floodplains formation due to precipitation changes over different timescales is a key issue to understand Amazonian biodiversity. Within this context, the Quaternary is particularly relevant, since it is a critical period for biotic diversification of the Amazonian biome. Here we will assess (i) changes in the provenance of siliciclastic sediments of different sources as well as fluvial discharge of the Amazon River during the last 1.93 Ma, and (ii) how these changes impacted the availability of floodplains. Through this project, we will improve the understanding about how changes in the distribution and connectivity of Quaternary Amazonian floodplains and upland fluvial terraces occurred and how these changes influenced the current biodiversity and dispersion of taxa adapted to seasonally flooded or upland habitats. By achieving these aims, we will produce a detailed Quaternary sedimentary history of floodplains in the Amazon Basin, allowing a better comparison between changes in the physical landscape and Quaternary speciation events.