University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Itzel Lopez Montoya
(2022):
Response of methanotrophic bacteria to soil drying and rewetting in Austrian forests.
Master / Diploma Thesis - Institut für Bodenforschung (IBF),
BOKU-Universität für Bodenkultur,
pp 67.
UB BOKU
obvsg
- Abstract:
- Methane (CH4) is a greenhouse gas with 28 times higher global warming potential than CO2, contributing 23% to global warming. Microbial oxidation by methanotrophic bacteria is the only biological sink for atmospheric CH4 with forest soils being the largest sink in terrestrial ecosystems. The main objective of this study is to investigate the spatio-temporal response of methanotrophic soil bacteria to environmental factors and multiple components of global change, specifically droughts, extreme precipitation events, and atmospheric N deposition. A soil drying-rewetting and N addition experiment was conducted during one year in a forest. A stress treatment excluded natural precipitation for eight weeks and was followed by a simulated intense precipitation event. It was expected that soil CH4 uptake will be higher during drought, due to higher gas diffusivity when the soil moisture content is low, and that after rewetting CH4 uptake will be reduced. It was also hypothesized CH4 uptake will be related to methanotroph abundance. Methanotrophic bacteria were analyzed with molecular techniques (ddPCR). Only Upland Soil Cluster alpha (USCα) type (not Type I or Type II was found in these soils) and their abundance was positively correlated with soil CH4 uptake. A higher abundance of USCa methanotrophs and a higher soil CH4 uptake was found during the drought periods than in the followed rewetting event. An N inhibition effect was found in soil CH4 uptake, and a negative correlation between ammonium and USCa methanotrophs was found. This study demonstrated the importance of USCa methanotrophs in oxidizing CH4 in forest soils and the impact of disturbances in the short term to the abundance of USCa and soil CH4 uptake.
- Beurteilende*r: Zechmeister-Boltenstern Sophie
- 1.Mitwirkender: Diaz-Pines Eugenio