The present study aims to evaluate the changes in diatom assemblages and also use them as biological markers for paleoenvironmental reconstruction for the Colônia crater (located in the Brazilian Coastal Plain, Mata Atlântica, Metropolitan Region of São Paulo). The Colônia crater has a circular structure of 3.6 km in diameter and its origin has been debated since the early 1960s. The continuous sedimentary filling of the area can provide a unique paleoenvironmental record for the southern hemisphere and in particular for the Atlantic rainforest evolution. The sedimentary core to be obtained in the crater along with this project collaborators presents an estimate of 800,000 years and 50 m deep (¹Sawakuchi, personal communication). The diatoms evaluation will allow access to the pre-existing communities before anthropogenic interference, as well as make inferences about environmental changes related to climate change during glacial and interglacial periods in the Atlantic Forest and eventual enrichment (eutrophication) process. Specifically, this project aims to (i) to access the diatom biodiversity and distribution in the colony crater; (ii) to interpret the environmental conditions and their changes during the study (iii) to subsidize the environmental reconstruction of the main changes occurred during glacial and interglacial periods in the Atlantic forest, specifically in relation to drier and rainy periods and the enrichment process. The sediment profiles will be analyzed by taxonomic, qualitative and quantitative analysis. Ecological information of taxa will be obtained through specialized literature, specific electronic addresses and the OMNIDIA program. The data will be analyzed by multivariate statistical analyzes and organized into stratigraphic diagrams. The present project brings unprecedented contribution to Brazil regarding its biodiversity and diatoms changes, as well as its use as a biological marker of environmental reconstruction on a scale of 800,000 years.
News published in Agência FAPESP Newsletter about the scholarship: