Analysis of CH4 and N2O Fluxes in the Dry Season: Influence of Soils and Vegetation Types in the Pantanal

This study examines CH4 and N2O fluxes during the dry season in two distinct areas of the Pantanal: Barranco Alto Farm (BAF), dominated by grasslands, and Passo da Lontra (PL), a forested region. As climate change increases the occurrence of droughts, understanding greenhouse gas (GHG) fluxes in tropical wetlands during dry periods is crucial. Using static chambers, CH4 and N2O emissions were measured from soils and tree stems in both regions, with additional measurements from grass in BAF. Contrary to expectations, PL-characterized by clayey soils-had sandy mud samples that retained less water, promoting oxic conditions and methane uptake, making it a CH4 sink. Meanwhile, BAF's sandy, well-drained soils exhibited minimal CH4 fluxes, with negligible methane uptake or emissions. N2O fluxes were generally higher in BAF, particularly from tree stems, indicating significant interactions between soil type, moisture, and vegetation. These findings highlight the pivotal roles of soil texture and aeration in GHG emissions, suggesting that well-drained, sandy soils in tropical wetlands may not always enhance methane oxidation. This underscores the importance of continuous GHG monitoring in the Pantanal to refine climate change mitigation strategies.