Banca de DEFESA: VINÍCIUS DE ANDRADE URBANO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: VINÍCIUS DE ANDRADE URBANO
DATA: 29/08/2025
HORA: 08:30
LOCAL: Anfiteatro do Departamento de Ecologia e Conservação
TÍTULO:

Methodological and Ecological insights into methane-derived carbon incorporation by fish in tropical ecosystems

PALAVRAS-CHAVES:

stable isotopes, methane, trophic niche

PÁGINAS: 200
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
SUBÁREA: Ecologia Aplicada
RESUMO:

Methane is a major greenhouse gas; in addition to human production, methane is widely produced in wetlands. However, the presence of fish in these ecosystems can contribute to reducing methane emissions. Before reaching the atmosphere, methane can be oxidized by methanotrophic bacteria and incorporated into the food chain. Stable carbon isotopes (δ¹³C) have been used to investigate the incorporation of methane-derived carbon in aquatic consumers, since aquatic invertebrates feed on methanotrophic bacteria and fish feed on these invertebrates. Therefore, the objective of this dissertation was: (i) to investigate the use of stable carbon isotopes to directly track the incorporation of methane-derived carbon in fish; (ii) to evaluate the incorporation of methane-derived carbon by apex fishes in four large Neotropical floodplains; (iii) to evaluate the incorporation of methane-derived carbon by fishes in a Neotropical reservoir and the role of non-native consumers in this dynamic; and (iv) investigate the influence of fish size, trophic guild, and seasonality on the assimilation of methane-derived carbon in floodplain lakes in a Neotropical region. The use of stable carbon isotopes can be considered an effective tool to directly estimate the incorporation of methane-derived carbon by fish, since methane has highly depleted δ¹³C values, allowing a clear distinction between this carbon source. Methane-derived carbon accounted for a significant proportion of fish biomass in different floodplains in South America, ranging from 5% to 15% of the carbon biomass. Higher levels of methane-derived carbon incorporation were observed in floodplains with higher methane production rates. Methane-derived carbon was also found to be an important energy source for fish in a Neotropical reservoir. However, non-native apex consumers pose a threat to this dynamic, as they feed primarily on the main assimilators of methane-derived carbon. Finally, the dynamics of methane-derived carbon uptake by fish appear to be strongly influenced by environmental characteristics, fish size, and seasonality, with no clear relationship to trophic guild. The rate of methane production and the availability of ecological links that transfer methane-derived carbon from methanotrophic bacteria to fish are the main drivers of its uptake in fisheries biomass. These findings also emphasize the importance of this carbon pathway in supporting fisheries biomass, a topic that has long been neglected. Furthermore, they highlight the important role of fish in incorporating methane-derived carbon into their biomass, ultimately contributing to the reduction of methane emissions, since methane oxidation and uptake in the food chain are inversely related to methane release. Therefore, these results highlight the importance of fisheries biomass conservation as a nature-based solution to natural methane emissions and methane emissions from artificial environments, such as reservoirs.

MEMBROS DA BANCA:
Interno - RUBENS MANOEL DOS SANTOS (Membro)
Externo à Instituição - RAFAEL PEREIRA LEITÃO - UFMG (Suplente)
Presidente - PAULO DOS SANTOS POMPEU (Membro)
Interno - MARCELO PASSAMANI (Suplente)
Externo à Instituição - LUCIANO FOGACA DE ASSIS MONTAG - UFPA (Membro)
Interno - CECÍLIA GONTIJO LEAL - LANCASTER (Membro)