State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
Sci Total Environ. 2020 May 20;718:137385. doi: 10.1016/j.scitotenv.2020.137385. Epub 2020 Feb 19.
Understanding the sensitivity of soil bacteria to environmental fluctuations can enhance the management of microbial ecosystem services in artificial mangrove wetlands. In this study, the variation in bacterial diversity and metabolic functions in different compartments (bulk soil, rhizosphere soil, and rhizoplane) of the soil and mangrove plant along the tidal elevation gradient was studied in Xiatanwei (Xiamen China) mangrove wetland park, a Kandelia obovata-dominated artificial mangrove stand. With the increase of the tidal flat elevation, the soil pH, total organic matter, and soil moisture contents decreased significantly, while the soil electric conductivity and redox potential increased significantly. The bacterial diversity in the bulk soil and the rhizosphere soil both decreased with the elevation of tidal levels. The relative abundance of the dominant phyla in the bulk and rhizosphere soils decreased with the rise of the tidal flat level. A significant rhizosphere effect was observed in the roots of K. obovata that the rhizosphere soil had higher bacterial diversity and richness than that in the bulk soil nearby. The rhizosphere soil of K. obovata at the low-tidal flat was enriched with the genera Nitrospira and Planctomycetes, which are valuable for the mangrove ecosystem. The Chao1 estimator and Shannon index of the bacterial community in the rhizoplane of K. obovata were much lower than that in the rhizosphere and bulk soils. Results of Biolog-Eco assay show that the bacterial groups in low tidal flat bulk soil had the highest ability in utilizing the carbon sources, which was indicated by the high values of average well color development and the high McIntosh index, and the utilization ability of carbon source decreased with the increase of tidal flat levels. The variation of the soil humidity and Eh jointly shaped the diversity and metabolic function of soil bacterial communities along the tidal flat elevation gradient.
了解土壤细菌对环境波动的敏感性可以增强人工红树林湿地中微生物生态系统服务的管理。本研究在中国厦门下潭尾红树林湿地公园，以秋茄（Kandelia obovata）为主导的人工红树林林分中，研究了沿潮滩高程梯度不同隔室（原状土、根际土和根面）土壤和红树林植物中细菌多样性和代谢功能的变化。随着潮滩高程的增加，土壤 pH 值、总有机碳和土壤水分含量显著降低，而土壤电导率和氧化还原电位显著升高。原状土和根际土中的细菌多样性均随潮位升高而降低。原状土和根际土中优势门的相对丰度随潮滩高程的升高而降低。在秋茄根中观察到显著的根际效应，即根际土壤的细菌多样性和丰富度高于附近的原状土壤。低潮滩的秋茄根际土壤富含硝化螺旋菌属和浮霉菌属等对红树林生态系统有价值的属。秋茄根面的细菌群落的 Chao1 估计值和 Shannon 指数明显低于根际和原状土壤。Biolog-Eco 测定结果表明，低潮滩原状土壤中细菌群体利用碳源的能力最高，这表现为平均好氧颜色发展值和 McIntosh 指数较高，而随着潮滩高程的增加，碳源利用能力降低。土壤湿度和 Eh 的变化共同塑造了沿潮滩高程梯度土壤细菌群落的多样性和代谢功能。
