Banca de DEFESA: ANALICE NUNES CLARINDO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANALICE NUNES CLARINDO
DATE: 28/02/2023
TIME: 14:00
LOCAL: Sala de aula da Pós-graduação em Produção Agricola
TITLE:

PALEOPEDOLOGICAL SIGNIFICANCE OF PHYTOLITHS IN A SEQUENCE OF SOILS WITH HIGH CARBON CONTENT IN THE CATIMBAU NATIONAL PARK, SEMIARID OF PERNAMBUCO.

KEY WORDS:

Podzols; silicon biomineralization; paleoenvironment

PAGES: 85
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Gênese, Morfologia e Classificação dos Solos
SUMMARY:

Pedology defines that the soil is the product of the alteration of the parent material by climate and organisms, in a topographical condition over time. This being constituted of a marker of environmental changes in addition to preserving other biological markers. Phytoliths are hydrated silica particles that plants biomineralize, which acquire the shape of the tissue that was crystallized and when this particle is deposited in the soil, it constitutes a fossil record that remains viable for long periods and, therefore, is a proxy of past vegetation. The Spodosols in the semi-arid region of Pernambuco was reported and according to the literature, the genesis of these soils and the accumulation of carbon is not explained in a dry climate, the current context of the semiarid region. In this context, the present study aimed to use the phytolith as a paleopedological indicator associated with other biological proxies (sponge spicules, diatom frustules and freshwater algal cysts) and organic markers (thermodegradation of organic matter, stable carbon isotopes and FTIR) in understanding Spodosol formation and carbon accumulation in the semi-arid region of Pernambuco. The toposequence under study, composed of four profiles, is located in the Catimbau National Park (PNC), at the base of the escarpment of the Tacaratú Formation, where a tectonic fault is reported next to it. Samples were collected for the composition of the modern assembly of the five phytophysiognomies of the PNC, a fossil assembly for the interpretation of its paleovegetal meaning, through phytolithic indices, and characterization of organic matter. The hierarchical grouping analysis of the results of the indices calculated from the fossil assemblages, associated with the other proxies, revealed three distinct environmental periods that are associated with three processes of soil formation: a drier period associated with pyrolysis, a period of transition of conditions arid areas for increased humidity associated with podzolization and a more humid period, due to the rise in the water table caused by the tectonic fault, associated with paludization. Another hierarchical clustering analysis showed that different horizons of fossil assemblages bear similarity to current modern assemblages. The results suggest that the meaning of phytoliths was an important proxy to elucidate carbon accumulation in semiarid regions and the polygenetic genesis of these soils.

COMMITTEE MEMBERS:
Presidente - MARCELO METRI CORREA - UFAPE
Interno - ALEXANDRE TAVARES DA ROCHA
Externo ao Programa - 1538852 - VALDOMIRO SEVERINO DE SOUZA JUNIOR - UFRPE