Molecular Microbiology Research 2024, Vol.14, No.2, 79-91 http://microbescipublisher.com/index.php/mmr 82 3.2Fungi Fungi are considered the primary decomposers of complex plant biomass, such as litter and deadwood, due to their ability to produce specific enzymes that break down recalcitrant organic matter (Baldrian, 2017). They play a pivotal role in forest ecosystems by decomposing leaf litter and deadwood, which are critical processes in biogeochemical cycles (Bani et al., 2018). Fungi also exhibit a succession of different taxa during decomposition, with ascomycete fungi being replaced by basidiomycetes as decomposition progresses (Purahong et al., 2016). Early-diverging fungi have been instrumental in shaping terrestrial ecosystems by interacting with plants and modifying the Earth's atmosphere (Berbee et al., 2017). Their ability to access new substrates through hyphae and produce powerful carbohydrate-active enzymes makes them indispensable in the decomposition process. 3.3 Actinomycetes Actinomycetes, a group of filamentous bacteria, are also significant contributors to the decomposition process. They are particularly effective in breaking down complex organic compounds, such as cellulose and lignin, which are abundant in plant biomass. Actinomycetes are known for their ability to produce a wide range of extracellular enzymes that facilitate the degradation of these complex molecules (Purahong et al., 2016). Their presence in decomposing leaf litter highlights their role in the microbial succession and their contribution to nutrient cycling and soil health. Actinomycetes, along with other bacterial groups, form part of the intricate microbial networks that drive the decomposition process and maintain ecosystem health. Bacteria, fungi, and actinomycetes each play distinct yet interconnected roles in the decomposition of organic matter. Bacteria are crucial for nutrient cycling and the decomposition of simpler compounds, fungi are the primary agents for breaking down complex plant materials, and actinomycetes contribute to the degradation of recalcitrant organic compounds. Together, these microbial groups ensure the efficient recycling of nutrients and the maintenance of ecosystem health. 4 Environmental Factors Affecting Decomposition 4.1 Temperature Temperature is a critical factor influencing the rate of microbial decomposition of organic matter. Numerous studies have demonstrated that higher temperatures generally accelerate decomposition processes by enhancing microbial activity and enzyme function. For instance, research has shown that decomposition rates are significantly higher at elevated temperatures, provided that sufficient moisture and oxygen are available (Sierra et al., 2017). Additionally, temperature sensitivity of soil organic matter (SOM) decomposition, expressed as the Q10 value, increases with rising temperatures, indicating a higher rate of decomposition with a 10°C increase in temperature (Wang et al., 2016). However, extreme temperatures can also have inhibitory effects. For example, high temperatures may reduce the heat capacity of extracellular enzymes or lead to moisture deficits, both of which can slow down decomposition (Sierra et al., 2017). Furthermore, temperature-driven changes in invertebrate communities can also impact decomposition rates, as higher temperatures have been found to reduce invertebrate abundance and diversity, thereby slowing down the decomposition process (Figueroa et al., 2021). 4.2 Moisture Soil moisture is another pivotal factor affecting decomposition rates. Moisture availability influences microbial activity by affecting substrate supply and oxygen concentration, which are essential for microbial respiration and enzyme activity (Sierra et al., 2015). Studies have shown that decomposition rates are highest at optimal moisture levels and decline when soil becomes either too dry or too saturated (Sierra et al., 2017). For instance, in boreal forest soils, decomposition rates were found to be high at high moisture levels, provided that oxygen was not limiting (Sierra et al., 2017). Similarly, research conducted along elevation gradients in Northeast China demonstrated that soil moisture significantly influences SOM decomposition rates, with higher moisture levels generally promoting faster decomposition (Wang et al., 2016). The interaction between temperature and moisture is also crucial, as the effects of temperature on decomposition can be modulated by soil moisture levels (Petraglia et al., 2018).
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