Soil Carbon, Nitrogen, and Phosphorus Cycling Microbial Populations and Their Resistance to Global Change Depend on Soil C:N:P Stoichiometry

Abstract

Maintaining stability of ecosystem functions in the face of global change calls for a better understanding regulatory factors of functionally specialized microbial groups and their population response to disturbance. In this study, we explored this issue by collecting soils from 54 managed ecosystems in China and conducting a microcosm experiment to link disturbance, elemental stoichiometry, and genetic resistance. Soil carbon:nitrogen:phosphorus (C:N:P) stoichiometry imparted a greater effect on the abundance of microbial groups associated with main C, N, and P biogeochemical processes in comparison with mean annual temperature and precipitation. Nitrogen cycling genes, including bacterial amoA-b, nirS, narG, and norB, exhibited the highest genetic resistance to N deposition. The amoA-a and nosZ genes exhibited the highest resistance to warming and drying-wetting cycles, respectively. Soil total C, N, and P contents and their ratios had a strong direct effect on the genetic resistance of microbial groups, which was dependent on mean annual temperature and precipitation. Specifically, soil C/P ratio was the main predictor of N cycling genetic resistance to N deposition. Soil total C and N contents and their ratios were the main predictors of P cycling genetic resistance to N deposition, warming, and drying-wetting. Overall, our work highlights the importance of soil stoichiometric balance for maintaining the ability of ecosystem functions to withstand global change. IMPORTANCE To be effective in predicting future stability of soil functions in the context of various external disturbances, it is necessary to follow the effects of global change on functionally specialized microbes related to C and nutrient cycling. Our study represents an exploratory effort to couple the stoichiometric drivers to microbial populations related with main C, N, and P cycling and their resistances to global change. The abundance of microbial groups involved in cellulose, starch, and xylan degradation, nitrification, N fixation, denitrification, organic P mineralization, and inorganic P dissolution showed a high stoichiometry dependency. Resistance of these microbial populations to global change could be predicted by soil C:N:P stoichiometry. Our work highlights that stoichiometric balance in soil C and nutrients is instrumental in maintaining the stability and adaptability of ecosystem functions under global change.

Effects of Imazapyr on Spartina alterniflora and Soil Bacterial Communities in a Mangrove Wetland

“…These indicate that bacterial diversity was not sensitive to the range of residues in the study and TOC, TP, AP, NH 4 + -N, and TN were the main factors, which might be due to the decomposition of chemicals and the reduction of S. alterniflora coverage, resulting in the changes of soil physicochemical properties [35]. It is well known that C, N, and P are the key factors affecting soil bacterial metabolism, influencing the nutrient source of bacteria [30]. After 30 days, the nutrient source pathway decreased with the decomposition of imazapyr in the soil, and the microbial abundance thus decreased.…”

“…According to Figure 3 and Table 2, the impact of plants on soil in the later stage was greater than that of imazapyr in the earlier stage. It may be due to the fact that the amount of imazapyr entering the soil was small and that it was degrading continuously, and that the reduction of plants directly and significantly changes TC and TOC, leading to the change of bacterial abundance and communities; and bacteria change the available soil nutrients through processes such as decomposition, mineralization, nitrification, and denitrification so as to form a cycle mechanism [30]. Furthermore, several studies have shown that imazapyr has little toxicity and is almost nontoxic to aquatic organisms [31][32][33][34].…”

Stronger microbial nutrient limitations in subsoil along the precipitation gradient of agroecosystem: Insights from soil enzyme activity and stoichiometry

“…Fertilizer for maize was applied with 200 kg N ha −1 , 70 kg P ha −1 and 90 kg K ha −1 as the base fertilizer at planting. The weeds were controlled using broad-spectrum herbicides and supplemented as required with manual hoeing (Guo et al, 2020). The soil types are classified as salt-alkali, light chernozem, chernozem, black soil, and dark brown soil, based on the Chinese soil classification system (Xiong and Li, 1987).…”

“…4). Therefore, soil C:N:P stoichiometry tremendously affected microbial groups involved in major biogeochemical processes (Luo et al, 2020). Additionally, balanced nutrient stoichiometry is essential for maintaining microbial and elemental homeostasis (Cui et al, 2019b).…”

Wildfire Alters the Linkage Between Total and Available Soil C:N:P Ratios and the Stoichiometric Effects on Fine Root Growth in a Chinese Boreal Larch Forest

“…A recent research showed that mineralization of SOM increased with available soil C:N and C:P ratios because available soil stoichiometry could shift microbial community composition by increasing organic matter mineralization to maintain the microbial stoichiometric homeostasis (Wei et al 2020). Likewise, total soil C:N:P stoichiometry can regulate soil C, N, and P biogeochemical processes through directly affecting the genetic resistance of microbial groups which involved in C, N, and P cycling (Luo et al 2020), and thus likely affect the supply of available soil N and P. Therefore, to fully appreciate the effects of wild re on biogeochemical processes, it is also vital to consider the relationships between total and available soil stoichiometry, which may provide new insight into re-induced ecological consequences.…”