Studying greenhouse gas emissions through interactions between phospholipid fatty acid content and soil properties of alpine grassland soil in Northern Tibet, China

Abstract

This study aimed to gain a better understanding of the carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes due to soil microbial community and soil physicochemical factors in Northern Tibet, China. We selected five types of grassland soils, incubated them under controlled temperature and humidity conditions, and analyzed the relationship between soil greenhouse gas (GHG) emissions and soil phospholipid fatty acids (PLFAs), soil bulk density, pH, soil organic carbon (SOC), dissolved organic carbon total nitrogen (TN), and total inorganic nitrogen content. The results showed that GHG emissions varied across different types of alpine grassland soils. The highest GHG fluxes occurred in alpine meadows, while the lowest fluxes occurred in alpine deserts, which could be explained based on the soil nutrient contents, including SOC and TN. In total, 23 microbial biomarker PLFAs were extracted from five types of alpine grassland soils to model the relationships between PLFAs and GHG emissions (or absorption) using backward regression analysis, over a three-month incubation experiment. Bacterial groups were responsible for CO2 emissions, while the initial quantities of bacteria and the fungi: bacteria ratio influence N2O emissions. Soils were the CH4 sink, and CH4 amount was influenced by the initial quantities of methane-oxidizing bacterial biomarkers (18:1ω5c) in Northern Tibet. Therefore, our findings showed that the microbial community structure and soil properties jointly explains the variation in soil GHG fluxes under specific environmental condition.