Multiproxy analysis (phytoliths, stable isotopes, and C/N) as indicators of paleoenvironmental changes in a Cerrado Site, Southern Brazil

Abstract

Cerrado vegetation is associated with the semi-humid climate of the Central Brazil highlands. The presence of this vegetation in small and sparse areas in Paraná, Southern Brazil, can be associated with its past climate conditions. Paleoenvironmental changes of Cerrado vegetation in the Campo Mourão region (24º06'S-52º23'W) are discussed in this study. The environmental changes were characterized using proxy data that includes stable isotopes and phytolith analyses in peaty sediments. Two drill cores obtained in alluvial plains were analyzed. Results were compared with the isotopic record (δ¹³C) from a trench in the Cerrado Ecological Station. Based on the results, we can infer that in ~48,800±270 yrs BP, the vegetation was mainly composed of grasses and at ~42,280 cal yrs BP a wetter climate allowed the expansion of arboreal vegetation. During the Middle Holocene (~7280 cal yrs BP), a drier period is also reported. Current climatic conditions (wet) were established since ~3280 cal yrs BP, after which the data suggests the expansion of subtropical forests over the Cerrado.

Antioxidant activity and physico-chemical analysis of Campomanesia rufa (O.Berg) Nied. fruits

“…The Cerrado biome occupies 22% of the Brazilian territory and houses a vast and diverse genetic heritage that is unique in the world (Reis;Schmiele, 2019). The Cerrado holds 40% of the endemic plant species and one-third of all Brazilian biodiversity (Luz et al, 2019). Many of the native Cerrado species produce fruits with commercial potential for natural consumption and the production of derivatives such as juices, jellies, and liquors (Neves et al, 2015).…”

Long and short-term pedogenetic processes in ferralsols from magmatic province of Paraná, Brazil

“…Once ferrihydrite is formed, hematite is favoured over goethite with increasing temperature in a drier climate. Therefore, the Hm content observed in the soil profiles G1 and G4 may have been formed under drier past climatic conditions during the Quaternary or older (see section 3.3.1) (Schwertmann, 1971;Behling, 1997;Ker, 1998;Ker and Resende, 1990;Luz et al, 2019). However, Almeida (1979) apud Ker (1998), reported that Fe 3+ contents in the system more than any other factor favour the formation of hematite.…”

“…Maghemite peaks were identified from the upper to deep soil horizons, probably formed from the oxidation of magnetite present in the parent material. The possibility of maghemite formation by transformation of other pedogenetic Fe oxides, such as Hm and Gt under high temperatures in the presence of organic C is not ignored, since, the Holocenic fires in a drier climate were recorded at the studied and nearby areas (see section 3.3.1) (Behling, 1997;Luz et al, 2019).…”

“…According to Behling (1998;, Calegari (2008), Bertoldo et al (2014), ), Pagotto et al (2020 and Wilson et al (2021) a drier climate was registered in the Mid-Holocene with a predominance of C4 plants, such as grassland in Southern Brazil. The modern predominant climatic conditions were stablished ~4000-3000 cal yrs BP in Paraná at the end of the Mid-Holocene (Pessenda et al, 1996;Behling, 1997;Stevaux, 2000;Calegari, 2008;Parolin et al, 2008;Beroldo et al, 2014;Luz et al, 2019;. The current expansion of Araucaria forest in Guarapuava soils (Period IV; 16), associated with a more humid and colder climate in the region.…”

“…Although less common, deeply weathered ferralsols with high carbon content are also reported in many tropical and subtropical areas, thereby providing potential paleoenvironmental records (Calegari et al, 2015;Luz et al, 2019). It is known that the soil organic matter (SOM) contains about three times more carbon than the atmosphere and terrestrial vegetation (Lal, 2004;Schmidt et al, 2011) and is an important source carbon potentially released into atmosphere.…”