Last millennium environmental changes and climate inferences in the Southeastern Atlantic forest, Brazil

Luiz C.R Pessenda,Marie-Pierre Ledru,José A Bendassolli,Susy E.M Gouveia,Paula G.C Amaral,Soraya E.M.G Saia,Abdelfettah Sifeddine

doi:10.1590/s0001-37652010000300019

Luiz C.R Pessenda, Marie-Pierre Ledru + Show 5 more

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https://doi.org/10.1590/s0001-37652010000300019

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Abstract

This study presents paleoenvironmental data based on pollen, elemental and isotopic compositions of organic matter (TOC, N, δ(13)C and δ(15)N) and (14)C dating of 170 cm lake sediment record. Samplings have been made in Lagoa Grande at Parque Estadual Turístico do Alto Ribeira - PETAR, Southern São Paulo State, Southeastern Brazil. The variations in relative frequencies (in percentage) of arboreal pollen along the core range between 40 and 80%. The δ(13)C values ranged from -23% to -30% and C/N of ~10 to 15, indicating the contribution of terrestrial C(3) plants and algae in the sediment organic matter. The δ(15)N results presented values from 3 to 4.5%, also suggesting a mixture of algae and terrestrial C(3) plants. The (14)C dating indicates modern age for the shallow horizons to ~1030 BP at the base of the core. A probable wetter climate in the period of ~370 BP to ~340 BP was inferred from the data set, which corresponds to a part of the period covered by the Little Ice Age (LIA).

Highlights

Lake systems are diverse, and the sources and alterations of organic matter are geographically and temporally variable
Pollen records obtained from lacustrine sediments have been used for palaeoenvironmental reconstruction studies during the late Quaternary and the Holocene in several regions of South America and Brazil (Absy and Correspondence to: Luiz Carlos Ruiz Pessenda E-mail: pessenda@cena.usp.br van der Hammen 1976, Absy et al 1991, Roth and Lorscheitter 1993, van der Hammen and Absy 1994, Colinvaux et al 1996, Ledru et al 1996, 2001, 2002, Behling 1995a, b, 1997a, b, 1998, 2002, Salgado-Labouriau et al 1998, Sifeddine et al 2001, 2003, Saia 2006)
This study shows the first lake sediment record regarding the last millennium in Brazil

Summary

Introduction

The sources and alterations of organic matter are geographically and temporally variable. Useful generalizations can be made about the different kinds of elemental, isotopic and palynologycal proxies that provide evidence of the origins and depositional histories of sedimentary organic matter and paleoenvironmental conditions (Meyers 2003). According to Meyers (2003), Sifeddine et al 2004 and Ortiz et al 2004, interpretation is not simple, in most cases, organic matter is a mixture of components from many sources and with variable degrees of preservation. Partial reworking and alteration of the original organic matter when sinking to the lake bottom, sedimentary organic matter retains important information on its origin, transportation and deposition, which helps paleoenvironmental reconstructions (Ortiz et al 2004)

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