Salinity and inundation drivers shift microbial necromass carbon distribution patterns in estuarine mangrove wetlands

作者：Linke Zheng, Manlin Su, Xiaoting Zhang, Lei Wang, Hualong Hong, Qian Zhang, Lijuan Zhong, Haoliang Lu · 发表于：Geoderma · 年份：2025 · DOI：10.1016/j.geoderma.2025.117413 · 被引用次数：9 · 研究领域：Coastal wetland ecosystem dynamics、Microbial Community Ecology and Physiology

• Microbial necromass contributed 27.1 % of SOC in coastal mangrove wetlands. • MNC contributed more to soil organic carbon in subsoil than in topsoil. • Fungal necromass plays a significant role in the soil organic carbon pool. • High salinity and inundation period inhibited the accumulation of MNC. Microbial necromass carbon (MNC) plays an important role in the long-term preservation of soil organic carbon (SOC) in coastal wetlands. However, the impact of increased salinity and inundation due to sea-level rise on MNC remains unclear. Here, we established a gradient experiment with three salinity levels (7.4 ‰, 15.6 ‰, 21.2 ‰) and four inundation periods (5 h/d, 7 h/d, 11 h/d, 13 h/d) across six mangrove sampling sites to investigate vertical distribution patterns of MNC and the environmental factors influencing its dynamics. Depth-resolved analyses revealed distinct MNC distribution patterns, and the topsoil (0–20 cm) exhibited considerably higher MNC concentrations (4.6–8.2 mg g −1 ) than the subsoil (3.0–5.4 mg g −1 , 40–50 cm), whereas the proportional contribution of MNC to SOC showed opposite trends (topsoil: 22.2 %–28.1 %; subsoil: 24.3 %–36.5 %). This inverse relationship suggests differential preservation mechanisms across soil depths. Different salinity and inundation periods induced pronounced responses. Under high salinity condition (21.2 ‰), MNC concentrations decreased by 30.2 % relative to those under low salinity conditions (7.4 ‰), and MNC/SOC showed a 13.6 ...