Banca de DEFESA: Lucas Cabrera Monteiro

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Lucas Cabrera Monteiro
DATE: 17/01/2023
TIME: 09:00
LOCAL: Virtual (Microsoft Teams)
TITLE:

Mercury bioaccumulation in the aquatic and terrestrial trophic chain of a neotropical floodplain

KEY WORDS:

Araguaia River basin; ecological risk; bioaccumulation; land use; floodplain.

PAGES: 150
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Mercury (Hg) is a chemical element naturally available in the earth's crust; however, its emission by human activities has become a global concern due to its ability to bioaccumulate in organisms and biomagnify along trophic chains. Therefore, the overall objective of this study is to quantify Hg concentrations in aquatic (water, sediment, plankton, macrophytes, periphyton, and fish) and terrestrial (soil, litter, vegetation, and invertebrates) environmental compartments of the Araguaia River floodplain, aiming to assess the bioaccumulation in biological communities and identify environmental variables that influence its distribution. Our results indicated that sediments presented low pollution levels and low to moderate ecological risk, with moderate to strong spatial dependence on land use intensity (Chapter 1). The bioaccumulation factor was highest in plankton, followed by periphyton and macrophytes. Hg concentrations in water were positively related to pH, and Hg in sediment was positively related to organic matter content. Concentrations in the macrophytes were positively influenced by Hg concentrations in the water and especially in the sediment. In periphyton, Hg concentrations were positively related to the proportion of burned areas, and Hg concentrations in macrophytes and inversely related to lake depth (Chapter 2). The bioaccumulation in fishes was highest in piscivores, followed by carnivores, omnivores, and detritivores. The biomagnification factor confirmed the biomagnification process among trophic guilds. The bioaccumulation was significantly related to fish length and weight; however, trophic level proved to be more important for Hg accumulation in our species pool (Chapter 3). In terrestrial ecosystems, Hg concentrations were significantly higher in the topsoil horizon and the litter compared to the deeper soil horizon and vegetation. Only organic matter content showed significant positive relationships with Hg concentrations in both soil depths. Hg concentrations in the invertebrates were positively related to litter concentrations and inversely related to soil concentrations. Among the most abundant orders, Araneae showed significantly higher concentrations than those determined in Hymenoptera and Orthoptera. Bioaccumulation factors calculated based on soil and litter showed distinct patterns among taxonomic groups, but significant bioaccumulation was determined in most samples (Chapter 4).

BANKING MEMBERS:
Externo à Instituição - RONALDO DE ALMEIDA - UNIR
Presidente - 1524495 - LUDGERO CARDOSO GALLI VIEIRA
Interno - 2285186 - MURILO SVERSUT DIAS
Interno - 1147029 - PEDRO HENRIQUE BRUM TOGNI