[目的] 研究红树林土壤微生物生物量与酶活性对不同淹水梯度的响应，揭示随淹水时间延长红树林下土壤质量的变化特征及影响因素，为该区域红树林保护与管理提供理论依据。 [方法] 以广东省雷州半岛附城镇红树林为研究对象，依据潮间带分布情况及红树林群落类型，采集低潮位、中低潮位、中潮位、中高潮位、高潮位表层0-20 cm沉积物样品，测定与分析红树林湿地不同潮位表层土壤微生物生物量碳(MBC)、氮(MBN)、磷(MBP)与酶活性。 [结果] 随淹水频率的增加，MBC，MBN分别减少96.7%和98.4%，在高潮位为最大值；MBP呈波浪式下降，在中高潮位为最大值；微生物熵碳(qMBC)、氮(qMBN)先增后降，微生物熵磷(qMBP)呈波浪式下降，qMBC，qMBN，qMBP均在中高潮位为最大值；土壤β-葡萄糖苷酶、酸性磷酸酶活性先增后降，在中高潮位为最大值，脲酶活性显著减少20.2%，在高潮位为最大值。冗余分析结果表明，qMBN，MBN，MBC是研究区红树林表层土壤酶活性变异的关键环境因素，可解释其变异的50.9%。 [结论] 淹水梯度的变化对湛江红树林湿地表层土壤微生物生物量和酶活性变化产生了显著影响。随淹水频率增加土壤质量总体呈衰退态势，建议适当增加研究区湿地土壤氮素供给以改善土壤质量，促进红树植树造林及其生长。
[Objective] The the responses of soil microbial biomass and enzyme activities to a flooding gradient in mangroves were determined to reveal the dynamics of soil quality and its influencing factors with increasing flooding period in order to provide a theoretical basis for mangrove protection and management. [Methods] We selected a mangrove plantation located in Fucheng town on the Leizhou peninsula, Guangdong Province, as the study site. We collected surface sediments (0-20 cm) from low, mid-low, mid, mid-high, and high-intertidal zones according to the distribution of intertidal zones and the type of mangrove communities. Soil microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP), and enzyme activities of different intertidal zones were measured and analyzed. [Results] As flooding frequency increased, MBC and MBN significantly decreased by 96.7% and 98.4%, respectively. The highest values were observed in the high-intertidal zone. The MBP fluctuated and decreased, with the highest value observed in the mid-high-intertidal zone. Microbial entropy carbon (qMBC) and nitrogen (qMBN) initially increased and then decreased with time, while the microbial entropy phosphorus (qMBP) fluctuated with a decreasing trend. The highest qMBC, qMBN, and qMBP values were observed in mid-high-intertidal zone. The activities of β-glucosidase and acid phosphatase initially rose and then declined, with the highest values observed in the mid-high-intertidal zone. The activities of urease significantly decreased by 20.2%, and the highest value was observed in the high-intertidal zone. Redundancy analysis indicated that qMBN, MBN, and MBC were the main factors influencing soil enzyme activities in the surface soil, accounting for 50.9% of the total variation in enzyme activities. [Conclusion] Flooding gradient had a significant effect on soil microbial biomass and enzyme activities, and soil fertility decreased substantially with increased flooding time. An increase in nitrogen fertilization may improve soil quality and promote mangrove afforestation and growth.