Carbon dioxide (CO₂) is the most important greenhouse gas in the atmosphere, which is mainly derived from microbial respiration in soil. Soil bacteria are an important part of the soil ecosystem and play an important role in the process of plant growth, mineralization, and decomposition of organic matter. In this paper, we discuss a laboratory incubation experiment that we conducted to investigate the CO₂ emissions and the underlying bacterial communities under the natural succession of halophyte vegetation in the Yellow River Delta by using high-throughput sequencing technology and PICRUSt functional prediction. The results showed that the bacterial abundance and diversity increased significantly along with the succession of halophyte vegetation. Metabolic function is the dominant function of soil bacteria in the study area. With the succession of halophyte vegetation, the rate of CO₂ emissions gradually increased, and were significantly higher in soil covered with vegetation than that of the bare land without vegetation coverage. These results helped to better understand the relationships of soil bacterial communities under the background of halophyte vegetation succession, which can help to make efficient strategies to mitigate CO₂ emissions and enhance carbon sequestration.

Global wetlands play a significant role as “blue carbon sinks”. Despite their relatively small coverage, they have enormous potential for carbon capture and sequestration, and also serve as an important natural source of atmospheric carbon dioxide (CO₂) and methane (CH₄). Wetland ecosystems are characterized by complex microbial interactions that mediate carbon (C) cycling processes, and also directly influence the dynamic changes of CO₂ and CH₄, underscoring the crucial role of microorganisms in these systems. Understanding the ecological significance of these gases and their response mechanisms to environmental changes is vital for mitigating the greenhouse effect and conserving ecosystems. This paper reviewed the major environmental challenges facing wetlands globally, such as salinization, over-fertilization, heavy metal input, and microplastic pollution, all influenced by human activities. Additionally, it examined their impact on microbial interactions that mediate the carbon cycle and related greenhouse gas emissions. This review highlighted the crucial role of microorganisms in these cycles and provided a microbial ecological perspective and theoretical foundation for promoting sustainable development and reducing greenhouse gas emissions in wetland areas.

Future climate models indicate an enhanced severity of regional drought and more frequent rewetting events, which may cause cascading impacts on the nitrogen cycle and nitrous oxide (N₂O) emissions, and the underlying microbial mechanism remains largely unknown. Here we conducted an incubation study on the impact of different soil moisture statuses on N₂O producers and N₂O reducers following the application of different fertilizer types (urea and manure) on a neutral vegetable soil. The different soil moisture treatments included 100% field capacity, drought, and rewetting (50% to 100% field capacity). Results showed that the N₂O emissions significantly decreased under drought conditions. Only ammonia-oxidizing archaea (AOA) and fungal nirK were well adapted to drought stress in the control soil. Different fertilizers modulated the resilience of the functional guilds. Ammonia-oxidizing bacteria (AOB), nirK-type denitrifying bacteria and nosZ clade (both I and II) showed significant resilience in both fertilized and non-fertilized soils in response to soil rewetting. Soil rewetting also changed the underlying microbial mechanisms of N₂O emissions. The results show a more significant negative relationship between N₂O emissions and nosZI clade at 100% field capacity, as well as nosZII clade after soil rewetting. We highlight the significant role of the nosZII clade following soil rewetting events, which might be one factor that led to relatively lower N₂O emissions compared to those at 100% field capacity. Our results provide new insights into developing mitigation strategies by fostering nosZII, which should be studied further in other cropland ecosystems or vegetable systems with frequent irrigation.