Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2021-05-25T03:32:57Z No. of bitstreams: 1 2018 - Eduardo Carvalho da Silva Neto.pdf: 4120105 bytes, checksum: eaf8d3d5ebf9f61865cde3446e0b0056 (MD5) Made available in DSpace on 2021-05-25T03:32:57Z (GMT). No. of bitstreams: 1 2018 - Eduardo Carvalho da Silva Neto.pdf: 4120105 bytes, checksum: eaf8d3d5ebf9f61865cde3446e0b0056 (MD5) Previous issue date: 2018-02-21 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. Soils observed today are the result of many factors that continuously change in space and time. Besides the soil characteristics, which reflect the balance of environmental conditions over time, soils preserve numerous proxies, such as the phytoliths, which provide very useful data about past climates and environments. Therefore, soils can be considered archives of paleoenvironmental changes. The general objective of this study was to increase the knowledge about soil genesis in upland environments of the Atlantic Forest biome in the Southeast region of Brazil, by the multiproxy study of soil profiles in toposequences. Eight profiles were sampled in the mountainous region of the Esp?rito Santo State. The soil profiles were characterized for their morphological, physical and chemical properties, as well as the isotopic analyzes (14C and ?13C). Phytoliths were extracted based on procedures described by Campos & Labouriau (1966), Piperno (2006) and Calegari et al. (2013) and identified according to the International Code for Phytolith Nomenclature (Madella et al., 2005). The soils in this study are characterized by its high organic matter contents, due to the cold and humid climate typical of the upland environments in Southeastern Brazil. The morphological differences and the evolution of the soils are conditioned by variations in topography. The main factors of soil formation in these environments are organisms, climate and topography. The soil profiles present isotopic variations (?13C) in depth, which indicates changes in vegetation during soil formation. The ages measured by the 14C dating of organic matter (humin fraction) correspond to the Quaternary, predominantly to the Upper Holocene (last 4.250 years). The earliest records date from the Pleistocene-Holocene transition (11,315 years cal BP) and the younger BP zero (Before Present). The phytolithic assemblages observed in the first centimeters of the soil profiles (0 - 10 cm) correspond to the phytolytic signature of the present vegetation, and the fossil assemblages of phytoliths preserved along the profiles indicate variations in the type of plant formation in the studied environments. In summary, four environmental moments are identified through multiproxy analysis: Environmental Moment I (~ before 11,315 years BP in toposequence 1; ~ before 2814 years BP in toposequence 2) corresponds to a drier and hotter period than current, which would have occurred before the beginning of the Holocene, with vegetation predominantly composed by C4 grasses, and a high occurrence of plants adapted to hot and dry environmental conditions. Environmental Moment II (in ~ 11,315 years BP in toposequence 1; between 2229- and 2814-years BP in toposequence 2) corresponds to paleohorizons buried in the toposequence 1 (P4T1) and express a period of cold and humid climate with dense forest vegetation interspersed with C3 grasses. Environmental Moment III (before ~ 1837 years BP in toposequence 1; in ~ 2063 years BP in toposequence 2) corresponds to a hot and dry climate recorded in the two study areas, with vegetation marked by C4 grasses adapted to conditions of lower humidity (Chloridoideae). Environmental Moment IV (from 1,837 - 1,698 years BP in toposequence 1, after 2063 years BP in toposequence 2) corresponds to the period of establishment of current climatic conditions (Cwb - subtropical altitude climate, with dry winter and mild summer), since the Upper Holocene. Os solos tais como observamos hoje s?o consequ?ncia de um conjunto de fatores que variam continuamente no espa?o e no tempo. Al?m das caracter?sticas ed?ficas, que refletem o equil?brio de condi??es ambientais em intervalos de tempo, os solos podem preservar in?meros proxies, como os fit?litos, que fornecem informa??es muito ?teis sobre antigos climas e ambientes. Portanto, os solos podem ser considerados arquivos de mudan?as paleoambientais. O objetivo geral deste estudo foi ampliar a compreens?o da g?nese de solos em ambientes altomontanos do bioma Mata Atl?ntica na regi?o Sudeste do Brasil, a partir do estudo multiproxy de perfis em duas topossequ?ncias. Foram coletados 8 perfis em duas topossequ?ncias na regi?o serrana do estado do Esp?rito Santo, nos munic?pios de Santa Maria de Jetib? e Castelo. Os perfis foram caracterizados quanto ?s suas propriedades morfol?gicas, f?sicas e qu?micas, bem como pelas an?lises isot?picas (14C e ?13C). Os fit?litos foram extra?dos de acordo com procedimentos baseados em Campos & Labouriau (1966), Piperno (2006) e Calegari et al. (2013) e identificados conforme o International Code for Phytolith Nomenclature (Madella et al., 2005). Os solos estudados s?o caracterizados, principalmente, pelos elevados teores de mat?ria org?nica, devido ao clima frio e ?mido, t?pico dos ambientes altomontanos. As diferen?as morfol?gicas e o est?gio de evolu??o dos solos s?o condicionados por varia??es na topografia. Dessa forma, constata-se que os principais fatores de forma??o dos solos nesses ambientes s?o os organismos, o clima e o relevo. Os perfis apresentam varia??es isot?picas (?13C) em profundidade, que sugerem mudan?as na vegeta??o durante a forma??o dos solos. As idades obtidas pela data??o 14C da mat?ria org?nica (fra??o humina) nos perfis estudados correspondem ao Quatern?rio, predominantemente ao Holoceno Superior (?ltimos 4.250 anos). Os registros mais antigos datam da transi??o Pleistoceno-Holoceno (11.315 anos cal. BP) e os mais jovens AP zero (Antes do Presente). As assembleias fitol?ticas observadas nos primeiros cent?metros dos solos (0 ? 10 cm) correspondem ? assinatura fitol?tica da vegeta??o atual e as assembleias f?sseis de fit?litos preservadas ao longo dos perfis indicam varia??es no tipo de forma??o vegetal nos ambientes estudados. Em s?ntese, s?o identificados 4 momentos ambientais atrav?s da an?lise multiproxy: Momento ambiental I (~antes de 11.315 anos cal AP na topossequ?ncia 1; ~antes de 2.814 anos cal AP na topossequ?ncia 2) corresponde a um per?odo mais seco e quente que o atual, que teria ocorrido antes do in?cio do Holoceno, com uma vegeta??o composta predominantemente por gram?neas C4, e uma alta ocorr?ncia de plantas adaptadas a condi??es ambientais quentes e secas. Momento ambiental II (em ~11.315 anos cal AP na topossequ?ncia 1; entre 2.229 e 2.814 anos cal AP na topossequ?ncia 2) corresponde aos paleohorizontes enterrados no topossequ?ncia 1 (P4T1) corresponde a um per?odo de de clima frio e ?mido com uma densa vegeta??o florestal intercalada com gram?neas C3. Momento ambiental III (antes de ~1.837 anos cal AP na topossequ?ncia 1; em ~2.063 anos cal AP na topossequ?ncia 2) corresponde a um per?odo de clima quente e seco registrado nas duas ?reas de estudo, com vegeta??o marcada por gram?neas C4 adaptadas a condi??es de menor umidade (Chloridoideae). Momento ambiental IV (a partir de 1.837 ? 1.698 anos cal AP na topossequ?ncia 1; depois de 2.063 anos cal AP na topossequ?ncia 2) corresponde ao per?odo de estabelecimento das condi??es clim?ticas atuais (Cwb - clima subtropical de altitude, com inverno seco e ver?o ameno), a partir do Holoceno Superior.