@phdthesis{0588504d-fee8-4a6f-bebf-932f2868fe0d,
  abstract     = {{Methane (CH₄) and carbon dioxide (CO₂) emissions from northern peatlands are<br/>important components of the global greenhouse gas (GHG) balance and are highly<br/>sensitive to climate change and permafrost degradation. This thesis investigates<br/>spatial and temporal patterns of GHG fluxes across peatland ecosystems, with a<br/>particular focus on the environmental controls regulating CH₄ and CO₂ exchange.<br/>Field measurements were conducted across Swedish peatlands using chamber<br/>systems and eddy covariance observations. Chamber measurements were used to<br/>study small-scale spatial variability in CH₄ fluxes and supported isotopic analyses<br/>of CH₄. Ecosystem-scale flux data from the ICOS Sweden station at Abisko-<br/>Stordalen were used to quantify annual GHG budgets across contrasting permafrost<br/>landforms, including palsa, thawing permafrost areas, and fully thawed fens. The<br/>study further evaluated how environmental drivers such as peat temperature,<br/>hydrology, light availability, and growing season length influence carbon exchange<br/>dynamics.<br/>The thesis also examines methodological challenges in peatland GHG research. In<br/>particular, the role of gap-filling approaches in reducing uncertainties and<br/>highlighting the importance of methodological choices for reliable annual budget<br/>estimates. In addition, stable isotope analyses (δ¹³C-CH₄) were used to explore<br/>whether peatland CH₄ processes and carbon dynamics can be adequately<br/>represented by single isotopic value. Temporal and spatial variations in isotopic<br/>composition were linked to environmental conditions, substrate availability, and<br/>microbial community composition.<br/>The results demonstrate that permafrost thaw strongly make changes in carbon<br/>cycling in peatlands by increasing CH₄ emissions and modifying CO₂ exchange<br/>patterns. Fully thawed systems showed greater CO₂ uptake during the growing<br/>season, but also higher ecosystem respiration rates, compared with palsa and<br/>partially thawed systems. CH₄ emissions were primarily controlled by peat<br/>temperature and hydrological conditions, while CO₂ dynamics were more strongly<br/>linked to growing season length and light availability. Furthermore, the findings<br/>emphasize that both spatial heterogeneity and methodological decisions<br/>significantly influence the interpretation of peatland carbon dynamics and GHG<br/>budgets.<br/>By integrating flux measurements, isotopic analyses, and methodological<br/>evaluation, this thesis provides new insights into the controls on GHG emissions in<br/>northern peatlands undergoing climate warming, extreme events such as drought<br/>and permafrost degradation.}},
  author       = {{Lakomiec, Patryk}},
  isbn         = {{978-91-90202-72-2}},
  keywords     = {{Greenhouse gases; wetlands; eddy covariance; chamber measurements; isotopic composition; controlling factors}},
  language     = {{eng}},
  publisher    = {{Department of Earth and Environmental Sciences, Lund University}},
  school       = {{Lund University}},
  title        = {{Greenhouse gases flux dynamics and controlling environmental factors in Northern wetlands}},
  url          = {{https://lup.lub.lu.se/search/files/257945367/e-spik_ex_Patryk.pdf}},
  year         = {{2026}},
}