Wang Shiyuan, Wang Jiaoyue, Xi Fengming, Yin Yan, Zhao Na, Han Yaopeng, Ling Honglin, Zhang Xiaoyu, Wang Zhonghui
Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
Department of Science, Shenyang Aerospace University, Shenyang, 110136, China.
Sci Rep. 2025 Jul 19;15(1):26243. doi: 10.1038/s41598-025-12080-w.
Soil labile organic carbon (LOC) fractions can respond rapidly to environmental changes and are crucial for soil carbon cycling. However, there are limited studies on the distribution of soil LOC fractions in urban wetlands along the urban-rural gradient. Understanding the dynamic changes in LOC fractions associated with microbial mechanisms in urban wetlands can inform management practices aimed at maximizing carbon storage in urban wetlands. In this study, using the urban-rural gradient approach, we investigated five typical wetlands in an urbanizing area of Shenyang City, China to examine changes in soil LOC fractions and associated microbial characteristics under the impacts of urbanization. The results showed that the average soil organic carbon (SOC) density of urban wetlands was approximately 23.16 kg/m. The proportions of soil light fraction organic carbon (LFOC), particulate organic carbon (POC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) to SOC content were 11.5-33.8%, 8.7-18.7%, 0.2-0.6% and 1.4-2.4%, respectively. Soil LOC fractions increased along urban-rural gradient, and decreased with soil depth increase. Soil LOC fractions in lake wetland were significantly higher than those in river wetland. The abundance of soil bacteria with 16S rRNA genes and carbon- fixing microorganisms with cbbL genes ranged from 2.79 × 10 to 5.36 × 10 copies/g dry soil and 3.48 × 10 to 9.87 × 10 copies/g dry soil, respectively. Urbanization significantly decreased the alpha diversity of cbbL-harboring microbes in the surface soil of wetlands (p < 0.05). Soil LOC fractions were significantly correlated with SOC across the five wetlands (p < 0.01), and positively correlated with bacteria possessing 16S rRNA and cbbL genes. The dominant microbial communities shifted from Gammaproteobacteria to Betaproteobacteria along urban-rural gradient. These results suggest that soil LOC fractions and cbbL-harboring microbial diversity and community composition in urban wetlands are significantly altered during urbanization. Urbanization and wetland type are important factors to consider for accurate carbon estimation in urban wetlands. Our study can provide valuable insights for decision-makers and urban planners to develop better management plans for urban wetlands.
土壤活性有机碳（LOC）组分能够对环境变化迅速做出响应，并且对土壤碳循环至关重要。然而，关于城市湿地土壤LOC组分沿城乡梯度分布的研究却很有限。了解城市湿地中与微生物机制相关的LOC组分动态变化，可为旨在最大化城市湿地碳储存的管理实践提供依据。在本研究中，我们采用城乡梯度方法，对中国沈阳市一个城市化地区的五个典型湿地进行了调查，以研究城市化影响下土壤LOC组分及相关微生物特征的变化。结果表明，城市湿地土壤有机碳（SOC）平均密度约为23.16 kg/m。土壤轻组有机碳（LFOC）、颗粒有机碳（POC）、溶解有机碳（DOC）和微生物量碳（MBC）占SOC含量的比例分别为11.5 - 33.8%、8.7 - 18.7%、0.2 - 0.6%和1.4 - 2.4%。土壤LOC组分沿城乡梯度增加，并随土壤深度增加而降低。湖泊湿地的土壤LOC组分显著高于河流湿地。土壤中具有16S rRNA基因细菌和具有cbbL基因的固碳微生物的丰度分别为2.79×10至5.36×10拷贝/克干土和3.48×10至9.87×10拷贝/克干土。城市化显著降低了湿地表层土壤中携带cbbL微生物的α多样性（p < 0.05）。在这五个湿地中，土壤LOC组分与SOC显著相关（p < 0.01），并且与具有16S rRNA和cbbL基因的细菌呈正相关。优势微生物群落沿城乡梯度从γ-变形菌转变为β-变形菌。这些结果表明，城市化过程中城市湿地土壤LOC组分以及携带cbbL微生物的多样性和群落组成发生了显著变化。城市化和湿地类型是准确估算城市湿地碳储量时需要考虑的重要因素。我们的研究可为决策者和城市规划者制定更好的城市湿地管理计划提供有价值的见解。
